path: root/proto/xextproto/specs/lbx.xml

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<article id="lbx">

<articleinfo>
   <title>Low Bandwidth X Extension</title>
   <subtitle>X Consortium Standard</subtitle>
   <authorgroup>
     <author>
       <firstname>Donna</firstname>
       <surname>Converse</surname>
     </author>
     <author>
       <firstname>Jim</firstname>
       <surname>Fulton</surname>
     </author>
     <author>
       <firstname>David</firstname>
       <surname>Lemke</surname>
     </author>
     <author>
       <firstname>Ralph</firstname>
       <surname>Mor</surname>
     </author>
     <author>
       <firstname>Keith</firstname>
       <surname>Packard</surname>
     </author>
     <author>
       <firstname>Ray</firstname>
       <surname>Tice</surname>
     </author>
     <author>
       <firstname>Dale</firstname>
       <surname>Tonogai</surname>
     </author>
   </authorgroup>
   <releaseinfo>X Version 11, Release &fullrelvers;</releaseinfo>
   <releaseinfo>Version 1.0</releaseinfo>
   <copyright><year>1996</year><holder>X Consortium</holder></copyright>

<legalnotice>
<para>
Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated
documentation files (the "Software"), to deal in the Software without
restriction, including without limitation
the rights to use, copy, modify, merge, publish, distribute, sublicense, and
sell copies of the Software,
and to permit persons to whom the Software is furnished to do so, subject to
the following conditions:
</para>
<para>
The above copyright notice and this permission notice shall be included in all
copies or substantial portions
of the Software.
</para>
<para>
THE SOFTWARE IS PROVIDED &ldquo;AS IS&rdquo;, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE X
CONSORTIUM BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
</para>
<para>
Except as contained in this notice, the name of the X Consortium shall not be
used in advertising or otherwise
to promote the sale, use or other dealings in this Software without prior
written authorization from the
X Consortium.
</para>
<para>X Window System is a trademark of The OpenGroup.</para>
</legalnotice>
</articleinfo>

<sect1 id='introduction'>
<title>Introduction</title>

<para>
Low Bandwidth X (LBX) is a network-transparent protocol for running X Window
System applications over transport channels whose bandwidth and latency are
significantly worse than that used in local area networks. It combines a
variety of caching and reencoding techniques to reduce the volume of data that
must be sent over the wire. It can be used with existing clients by placing a
proxy between the clients and server, so that the low bandwidth/high latency
communication occurs between the proxy and server.
</para>


<para>
This extension was designed and implemented by Jim Fulton, David Lemke, Keith
Packard, and Dale Tonogai, all of Network Computing Devices (NCD). Chris Kent
Kantarjiev (Xerox PARC) participated in early design discussions. Ralph Mor (X
Consortium) designed and implemented additional sections. Donna Converse (X
Consortium) authored the protocol description and encoding from design notes
and the implementation. Ray Tice (X Consortium) resolved the open issues in the
design and specification. Bob Scheifler (X Consortium) helped out in many areas.
</para>


<para>
The extension name is &quot;LBX&quot;.
</para>


</sect1>
<sect1 id='description'>
<title>Description</title>

<para>
The design center for LBX is to use a proxy as an intermediary between the
client and server. The proxy reencodes and compresses requests, events, replies
and errors, as well as the resulting data stream. Additionally, the proxy can
cache information from the server to provide low-latency replies to clients.
This reply generation by the proxy is known as short-circuiting. A proxy can
handle multiple clients for a given server, but does not prevent clients from
connecting directly to the server. The design allows the proxy to multiplex
multiple clients into a single data stream to the server.
</para>


<para>
Much of LBX is implemented as an extension. The compression and reencoding
changes can be isolated to the transport and dispatch portions of the server,
while short-circuiting requires minor changes to the server’s colormap and
property code.
</para>


<para>
LBX employs several different compression and short-circuiting methods. Use of
these methods is negotiable, and in some cases, the algorithm used by a given
method is negotiable as well. LBX also provides for negotiation of extensions
to LBX.
</para>


<sect2 id='data_flow'>
<title>Data Flow</title>

<para>
The LBX data stream goes through a number of layers:
</para>


<orderedlist>
  <listitem>
<para>Client requests</para>
  </listitem>
  <listitem>
<para>Read by LBX and potential byte-swapping</para>
  </listitem>
  <listitem>
<para>Request-specific compression</para>
  </listitem>
  <listitem>
<para>Potential byte swapping</para>
  </listitem>
  <listitem>
<para>Multiplexing of client request streams</para>
  </listitem>
  <listitem>
<para>Delta replacement</para>
  </listitem>
  <listitem>
<para>Stream compression</para>
  </listitem>
</orderedlist>

<para>
Transport
</para>

<!-- FIXME:  descending -->
<orderedlist>
  <listitem>
<para>Stream decompression</para>
  </listitem>
  <listitem>
<para>Delta substitution</para>
  </listitem>
  <listitem>
<para>Demultiplexing of client request streams</para>
  </listitem>
  <listitem>
<para>Potential byte swapping</para>
  </listitem>
  <listitem>
<para>Reencoding</para>
  </listitem>
  <listitem>
<para>Request processing</para>
  </listitem>
</orderedlist>

<para>
The reverse process occurs with X server replies, events, and errors.
</para>


</sect2>
<sect2 id='tags'>
<title>Tags</title>

<para>
Tags are used to support caching of large data items that are expected to be
queried multiple times. Such things as the keyboard map and font metrics are
often requested by multiple clients. Rather than send the data each time, the
first time the data is sent it includes a tag. The proxy saves this data, so
that subsequent requests can send only the tag to refer to that same data. The
different types of tags are used for connection information, keyboard maps,
modifier maps, fonts information and properties.
</para>


<para>
Tag usage is negotiated as a boolean in the <emphasis>
LbxStartProxy</emphasis>
 message. The proxy controls how many tags are stored in the proxy. The server
may wish to observe the proxy’s InvalidateTag behavior to limit how many tags
are cached at any one time. Tagged data is not shared across types of tags, but
the number space used for the tag ids is. The tag ids are generated by the
server.
</para>


<para>
The X server keeps track of what tags are known to the proxy. The proxy can
invalidate a tag if no tag bearing replies of that type are pending. The proxy
sends an <emphasis>
LbxInvalidateTag</emphasis>
 message to release the tagged data. The proxy must not invalidate connection
tags unless instructed to do so by the server.
</para>


<para>
If the server wishes to discard tagged data, it must either have received an
<emphasis>
LbxInvalidateTag</emphasis>
 request from the proxy or send an <emphasis>
LbxInvalidateTag</emphasis>
 event to the proxy for that tag.
</para>


<sect3 id='tag_substitution_in_requests'>
<title>Tag Substitution in Requests</title>

<para>
Many substitution requests have a tag field, followed by fields marked
optional. For these requests, if the optional fields are present, the
data in them is stored in the indicated tag, unless the tag is 0. If
the optional fields are absent, the tag field indicates the tag that
contains the data for the &quot;optional&quot; fields.
</para>


</sect3>
<sect3 id='property_tags'>
<title>Property Tags</title>

<para>
Property data makes special use of tags. A common use of properties is for
inter-client communication. If both clients use the proxy, it is wasteful to
send the data to the server and then back, when the server may never need it.
<emphasis>
LbxChangeProperty</emphasis>
 request does the same work as the core <emphasis>
ChangeProperty</emphasis>
 request, but it does not send the data. The reply to this request contains a
tag id corresponding to the data. If the property information is used locally,
the server responds to <emphasis>
LbxGetProperty</emphasis>
 with the tag, and the property data need never be sent to the server. If the
server does require the data, it can issue an <emphasis>
LbxQueryTag</emphasis>
 message. The proxy can also send the data on at any time if it judges it
appropriate (i.e., when the wire goes idle). Since the proxy owns the property
data, it must not invalidate the tag before sending the data back to the server
via an <emphasis>
LbxTagData</emphasis>
 request.
</para>


</sect3>
</sect2>
<sect2 id='short_circuiting'>
<title>Short-circuiting</title>

<para>
Short-circuiting is used to handle constant data. This includes atoms, color
name/RGB mappings, and <emphasis>
AllocColor</emphasis>
 calls. Atoms and color name/RGB mappings stay constant for the life of the
server. <emphasis>
AllocColor</emphasis>
<emphasis>
 </emphasis>
replies are constant for each colormap. Short-circuiting replaces round-trip
requests with one-way requests, and can sometimes use one in place of many.
</para>


<para>
Atoms are used heavily for ICCCM communication. Once the proxy knows the string
to atom mapping, it has no need to send subsequent requests for this atom to
the server.
</para>


<para>
Colorname/RGB mappings are constant, so once the proxy sees the response from
<emphasis>
LookupColor</emphasis>
, it need not forward any subsequent requests.
</para>


<para>
Clients often use the same color cells, so once a read-only color allocation
has occurred, the proxy knows what RGB values should be returned to the client.
The proxy doesn't need to forward any <emphasis>
AllocColor</emphasis>
 requests it can resolve, but it must tell the server to modify the color
cell's reference count. <emphasis>
LbxIncrementPixel</emphasis>
 is used to support this.
</para>


<para>
For all three classes of short-circuiting, the proxy must still tell the server
a request has occurred, so that the request sequence numbers stay in sync. This
is done with <emphasis>
LbxModifySequence</emphasis>
.
</para>


<para>
Sequence numbers cause the major complication with short-circuiting. X
guarantees that any replies, events or errors generated by a previous request
will be sent before those of a later request. This means that any requests that
can be handled by the proxy must have their reply sent after any previous
events or errors.
</para>


<para>
If a proxy’s applications do not require strict adherence to the X protocol
ordering of errors or events, a proxy might provide further optimization by
avoiding the overhead of maintaining this ordering, however, the resulting
protocol is not strictly X11 compliant.
</para>


</sect2>
<sect2 id='graphics_re_encoding'>
<title>Graphics Re-encoding</title>

<para>
The LBX proxy attempts to reencode <emphasis>PolyPoint</emphasis>,
<emphasis>PolyLine</emphasis>, <emphasis>PolySegment</emphasis>,
<emphasis>PolyRectangle</emphasis>, <emphasis>PolyArc</emphasis>,
<emphasis>FillPoly</emphasis>, <emphasis>PolyFillRectangle</emphasis>,
<emphasis>PolyFillArc</emphasis>, <emphasis>CopyArea</emphasis>,
<emphasis>CopyPlane</emphasis>, <emphasis>PolyText8</emphasis>,
<emphasis>PolyText16</emphasis>, <emphasis>ImageText8</emphasis>,
and <emphasis>ImageText16</emphasis> requests. If the request can be
reencoded, it may be replaced by an equivalent LBX form of the request.
The requests are reencoded by attempting to reduce 2-byte coordinate,
length, width and angle fields to 1 byte. Where applicable, the
coordinate mode is also converted to <emphasis>Previous</emphasis>
 to improve the compressibility of the resulting data. In image requests,
the image data may also be compressed.
</para>

</sect2>
<sect2 id='motion_events'>
<title>Motion events</title>

<para>
To prevent clogging the wire with <emphasis>MotionNotify</emphasis>
 events, the server and proxy work together to control the number
of events on the wire. This is done with the
<emphasis>LbxAllowMotion</emphasis>
 request. The request adds an amount to an allowed motion count in
the server, which is kept on a per-proxy basis. Every motion notify
event sent to the proxy decrements the allowed motion counter. If
the allowed motion count is less than or equal to zero, motion
events not required by the X protocol definition are not sent to the
proxy. The allowed motion counter has a minimum value of -2^31.
</para>

</sect2>
<sect2 id='event_squishing'>
<title>Event Squishing</title>

<para>
In the core protocol, all events are padded as needed to be 32 bytes long. The
LBX extension reduces traffic by removing padding at the end of events, and
implying the event length from its type. This is known as squishing.
</para>

</sect2>
<sect2 id='master_client_'>
<title>Master Client </title>

<para>
When the initial X connection between the proxy and the server is converted to
LBX mode, the proxy itself becomes the master client. New client requests and
some tag messages are sent in the context of the master client.
</para>


</sect2>
<sect2 id='multiplexing_of_clients'>
<title>Multiplexing of Clients</title>

<para>
The LBX proxy multiplexes the data streams of all its clients into one stream,
and then splits them apart again when they are received. The <emphasis>
LbxSwitch</emphasis>
 message is used to tell each end which client is using the wire at the time.
</para>


<para>
The server should process delta requests in the order that they appear on the
LBX connection. If the server does not maintain the interclient request order
for requests sent by the proxy, it must still obey the semantics implied by the
interclient request order so that the delta cache functions correctly.
</para>


<para>
The server can affect the multiplexing of clients by the proxy using the
<emphasis>
LbxListenToOne</emphasis>
 and <emphasis>
LbxListenToAll</emphasis>
 messages. This is useful during grabs, since the master connection can not be
blocked during grabs like other clients. The proxy is responsible for tracking
server grabs issued by its clients so that the proxy can multiplex the client
streams in an order executable by the server.
</para>


<para>
Replies must be ordered in the multiplexed data stream from the server to the
proxy such that the reply carrying tagged data precedes replies that refer to
that tagged data.
</para>


</sect2>
<sect2 id='swapping'>
<title>Swapping</title>

<para>
Swapping is handled as with any X extension, with one caveat. Since a proxy can
be supporting clients with different byte orders, and they all share the same
wire, the length fields of all messages between the server and proxy are
expressed in the proxy byte order. This prevents any problems with length
computation that may occur when clients are switched.
</para>


</sect2>
<sect2 id='delta_cache'>
<title>Delta cache</title>

<para>
LBX takes advantage of the fact that an X message may be very similar to one
that has been previously sent. For example, a <emphasis>
KeyPress</emphasis>
 event may differ from a previous <emphasis>
KeyPress</emphasis>
 event in just a few bytes. By sending just the bytes that differ (or
"deltas"), the number of bytes sent over the wire can be substantially reduced.
Delta compaction is used on requests being sent by the proxy as well as on
replies and events being sent by the server.
</para>


<para>
The server and the proxy each keep per-proxy request and response caches. The
response cache contains events, errors and replies. All messages are saved in
the appropriate delta cache if they are of an appropriate type and more than 8
bytes long but fit within the delta cache. The number of entries in the delta
cache and the maximum saved message size are negotiated in the <emphasis>
LbxStartProxy</emphasis>
 request.
</para>


<para>
The LBX requests that are never stored in the request delta cache are the
<emphasis>
LbxQueryVersion</emphasis>
, <emphasis>
LbxStartProxy</emphasis>
, <emphasis>
LbxSwitch</emphasis>
, <emphasis>
LbxNewClient</emphasis>
, <emphasis>
LbxAllowMotion</emphasis>
, <emphasis>
LbxDelta</emphasis>
, <emphasis>
LbxQueryExtension</emphasis>
, <emphasis>
LbxPutImage</emphasis>
, <emphasis>
LbxGetImage</emphasis>
, <emphasis>
LbxBeginLargeRequest</emphasis>
, <emphasis>
LbxLargeRequestData</emphasis>
, <emphasis>
LbxEndLargeRequest</emphasis>
 and <emphasis>
LbxInternAtoms</emphasis>
 requests. The responses that are never stored in the response cache are
<emphasis>
LbxSwitchEvent</emphasis>
 and <emphasis>
LbxDeltaResponse</emphasis>
. The message carried by a <emphasis>
delta </emphasis>
message is also cached, if it meets the other requirements. Messages after the
<emphasis>
LbxStartProxy</emphasis>
 request are cached starting at index 0, and incrementing the index, modulo the
number of entries, thereafter. The request and response caches are
independently indexed.
</para>


<para>
If the current message is cachable and the same length as a message in the
corresponding delta cache, a delta message may be substituted in place of the
original message in the protocol stream.
</para>


</sect2>
<sect2 id='stream_compression'>
<title>Stream Compression</title>

<para>
Before being passed down to the transport layer messages can be passed through
a general purpose data compressor. The choice of compression algorithm is
negotiated with <ulink url="lbx.htm#20870">See LbxStartProxy</ulink>. The proxy
and server are not required to support any specific stream compressor. As an
example, however, the X Consortium implementation of a ZLIB based compressor is
described below.
</para>

<note><para>
The XC-ZLIB compressor is presented with a simple byte stream - the X and LBX
message boundaries are not apparent. The data is broken up into fixed sized
blocks. Each block is compressed using zlib 1.0 (by Gailly &amp; Adler), then a
two byte header is prepended, and then the entire packet is transmitted. The
header has the following information:
</para></note>
<para><programlisting>
      out[0] = (length &amp; 0xfff) &gt;&gt; 8 | ((compflag) ? 0x80 : 0);
      out[1] = length &amp; 0xff;
</programlisting></para>

</sect2>
<sect2 id='authentication_protocols'>
<title>Authentication Protocols</title>

<para>
The current version of LBX does not support multipass authentication protocols
for clients of the proxy. These authentication protocols return an <emphasis>
Authenticate</emphasis>
 message in response to a connection setup request, and require additional
authentication data from the client after the <emphasis>
LbxNewClient</emphasis>
 request, and before the reply to <emphasis>
LbxNewClient</emphasis>
. One example of such a protocol is XC-QUERY-SECURITY-1.
</para>


</sect2>
</sect1>
<sect1 id='c_library_interfaces_'>
<title>C Library Interfaces </title>

<para>
The C Library routines for LBX are in the Xext library. The prototypes are
located in a file named &quot;XLbx.h&quot;.
</para>


<sect2 id='application_library_interfaces'>
<title>Application Library Interfaces</title>

<para>
In a proxy environment, applications do not need to call these routines to take
advantage of LBX. Clients can, however, obtain information about the LBX
extension to the server using this interface. Use of this routine may be
altered when connected through a proxy, as described in <ulink
url="lbx.htm#33319">See C Library Interfaces</ulink>.
</para>


<sect3 id='xlbxqueryversion'>
<title>XLbxQueryVersion</title>

<para>
To determine the version of LBX supported by the X server, call <emphasis>
XLbxQueryVersion</emphasis>
.
</para>

<funcsynopsis>
<funcprototype>
<funcdef>Bool <function>XLbxQueryVersion</function></funcdef>
      <paramdef>Display * <parameter>display</parameter></paramdef>
      <paramdef>int * <parameter>major_version_return</parameter></paramdef>
      <paramdef>int * <parameter>minor_version_return</parameter></paramdef>
</funcprototype>
</funcsynopsis>

<variablelist>
  <varlistentry>
    <term>display</term>
    <listitem><para>Specifies the connection to the X server.</para></listitem>
  </varlistentry>
  <varlistentry>
    <term>major_version_return</term>
    <listitem><para>Returns the extension major version number.</para></listitem>
  </varlistentry>
  <varlistentry>
    <term>minor_version_return</term>
    <listitem><para>Returns the extension minor version number.</para></listitem>
  </varlistentry>
</variablelist>

<para>
The <emphasis>
XLbxQueryVersion</emphasis>
 function determines if the LBX extension is present. If the extension is not
present, <emphasis>
XLbxQueryVersion</emphasis>
 returns <emphasis>
False</emphasis>
; otherwise, it returns <emphasis>
True</emphasis>
. If the extension is present, <emphasis>
XLbxQueryVersion</emphasis>
 returns the major and minor version numbers of the extension as supported by
the X server.
</para>


</sect3>
</sect2>
<sect2 id='proxy_library_interfaces'>
<title>Proxy Library Interfaces</title>

<para>
The following interfaces are intended for use by the proxy.
</para>

<sect3 id='xlbxqueryextension'>
<title>XLbxQueryExtension</title>

<para>
To determine the dynamically assigned codes for the extension, use the Xlib
function <emphasis>
XQueryExtension</emphasis>
 or the LBX function <emphasis>
XLbxQueryExtension</emphasis>
.</para>


<funcsynopsis>
<funcprototype>
<funcdef>Bool <function>XLbxQueryExtension</function></funcdef>
      <paramdef>Display * <parameter>display</parameter></paramdef>
      <paramdef>int * <parameter>major_opcode_return</parameter></paramdef>
      <paramdef>int * <parameter>first_event_return</parameter></paramdef>
      <paramdef>int * <parameter>first_error_return</parameter></paramdef>
</funcprototype>
</funcsynopsis>

<variablelist>
  <varlistentry>
    <term>display</term>
    <listitem><para>Specifies the connection to the X server.</para></listitem>
  </varlistentry>
  <varlistentry>
    <term>major_opcode_return</term>
    <listitem><para>Returns the major opcode.</para></listitem>
  </varlistentry>
  <varlistentry>
    <term>first_event_return</term>
    <listitem><para>Returns the first event code.</para></listitem>
  </varlistentry>
  <varlistentry>
    <term>first_error_return</term>
    <listitem><para>Returns the first error code.</para></listitem>
  </varlistentry>
</variablelist>

<para>
The <emphasis>
XLbxQueryExtension</emphasis>
 function determines if the LBX extension is present. If the extension is not
present, <emphasis>
XLbxQueryExtension</emphasis>
 returns <emphasis>
False</emphasis>
; otherwise, it returns <emphasis>
True</emphasis>
. If the extension is present, <emphasis>
XLbxQueryExtension</emphasis>
 returns the major opcode for the extension to major_opcode_return, the base
event type code to first_event_return, and the base error code to
first_error_return; otherwise, the return values are undefined.
</para>

</sect3>

<sect3 id='xlbxgeteventbase'>
<title>XLbxGetEventBase</title>
<para>
To determine the base event type code, use the Xlib function <emphasis>
XQueryExtension</emphasis>
 or the LBX function <emphasis>
XLbxGetEventBase</emphasis>.
</para>


<funcsynopsis>
<funcprototype>
<funcdef>int <function>XLbxGetEventBase</function></funcdef>
      <paramdef>Display * <parameter>display</parameter></paramdef>
</funcprototype>
</funcsynopsis>

<variablelist>
  <varlistentry>
    <term>display</term>
    <listitem><para>Specifies the connection to the X server.</para></listitem>
  </varlistentry>
</variablelist>

<para>
The <emphasis>XLbxGetEventBase</emphasis>
function returns the base event type code if the extension is
present; otherwise, it returns -1.
</para>

</sect3>
</sect2>
</sect1>


<sect1 id='protocol'>
<title>Protocol</title>

<sect2 id='syntactic_conventions_and_common_types'>
<title>Syntactic Conventions and Common Types</title>

<para>
Please refer to the X Window System Protocol specification,
as this document uses the syntactic conventions established
there and references types defined there.
</para>


<para>
The following additional types are defined by this extension:
</para>

<literallayout>
<emphasis role='bold'>DIFFITEM</emphasis>
1      CARD8      offset
1      CARD8      diff
</literallayout>

<literallayout>
<emphasis role='bold'>LBXANGLE: CARD8 or 2 BYTE</emphasis>
      where (in order of precedence):
      (0 &lt;= in &lt;= A(95)) &amp;&amp; !(in % A(5))       out = 0x5a + (in /
A(5))
      A(105) &lt;= in &lt;= A(360) &amp;&amp; !(in % A(15))      out = 0x67 +
(in / A(15))
      -A(100) &lt;= in &lt;= -A(5) &amp;&amp; !(in % A(5))      out = 0xa6 +
(in / A(5))
      -A(360) &lt; in &lt;= -A(105) &amp;&amp; !(in % A(15))      out = 0x98 +
(in / A(15))
      -A(360) &lt; in &lt;= A(360)      out[0] = in &gt;&gt; 8; out[1] = in
</literallayout>

<literallayout>
<emphasis role='bold'>LBXARC:</emphasis>
      [x, y: LBXINT16,
      width, height: LBXCARD16,
      angle1, angle2: LBXANGLE]
</literallayout>

<para>
Within a list of arcs, after the first arc, x and y are
relative to the corresponding fields of the prior arc.
</para>

<literallayout>
<emphasis role='bold'>LBXCARD16: CARD8 or 2 BYTE</emphasis>
      where:
      0x0000 &lt;= in &lt; 0x00F0      CARD8
      0x00F0 &lt;= in &lt; 0x10F0      out[0] = 0xF0 | ((in - 0xF0) &gt;&gt;
8)
            out[1] = in - 0xF0
</literallayout>

<literallayout>
<emphasis role='bold'>LBXGCANDDRAWENT</emphasis>
[ gc-cache-index, drawable-cache-index: CARD4 ]
</literallayout>

<literallayout>
<emphasis role='bold'>LBXGCANDDRAWUPDATE</emphasis>
      drawable: DRAWABLE      /* present only if
<emphasis>drawable-cache-index</emphasis>
 == 0 */
gc: GC]      /* present only if <emphasis>gc-cache-index</emphasis> == 0 */
</literallayout>

<literallayout>
<emphasis role='bold'>LBXGCANDDRAWABLE</emphasis>
      cache-entries: LBXGCANDDRAWENT
      updates: LBXGCANDDRAWUPDATE
</literallayout>

<literallayout>
<emphasis role='bold'>LBXINT16</emphasis>: INT8 or 2 BYTE
      where:
      0xF790 &lt;= in &lt; 0xFF90      out[0] = 0x80 | (((in + 0x70) &gt;&gt;
8) &amp; 0x0F)
            out[1] = in + 0x70
      0xFF90 &lt;= in &lt; 0x0080      CARD8
      0x0080 &lt;= in &lt; 0x0880      out[0] = 0x80 | (((in - 0x80) &gt;&gt;
8) &amp; 0x0F)
            out[1] = in - 0x80
</literallayout>

<literallayout>
<emphasis role='bold'>LBXPINT16</emphasis>: CARD8 or 2 BYTE       /* for
usually positive numbers */
      where:
      0xFE00 &lt;= in &lt; 0x0000      out[0] = 0xF0 | (((in + 0x1000)
&gt;&gt; 8) &amp; 0x0F)
            out[1] = in + 0x1000
      0x0000 &lt;= in &lt; 0x00F0       CARD8
      0x00F0 &lt;= in &lt; 0x0EF0      out[0] = 0xF0 | ((in - 0xF0) &gt;&gt;8)
            out[1] = in - 0xF0
</literallayout>

<literallayout>
<emphasis role='bold'>LBXPOINT</emphasis>: [x, y: LBXINT16]
      Within a list of points, after the first rectangle, x and y are
relative to the corresponding fields of the prior point.
</literallayout>

<literallayout>
<emphasis role='bold'>LBXRECTANGLE</emphasis>:
      [x, y: LBXINT16,
      width, height: LBXCARD16]
</literallayout>

<para>
Within a list of rectangles, after the first rectangle, x and
y are relative to the corresponding fields of the prior rectangle.
</para>

<para>
MASK: CARD8
</para>


</sect2>
<sect2 id='errors'>
<title>Errors</title>

<para>
As with the X11 protocol, when a request terminates with an error,
the request has no side effects (that is, there is no partial execution).
</para>


<para>
There is one error, <emphasis>
LbxClient</emphasis>
. This error indicates that the client field of an LBX request was invalid, or
that the proxy’s connection was in an invalid state for a start or stop proxy
request.
</para>


</sect2>
<sect2 id='requests'>
<title>Requests</title>

<para>
There is one request that is expected to be used only by the client: <emphasis>
LbxQueryVersion</emphasis>
</para>


<para>
There is one request that is expected to be used by the client or the proxy:
<emphasis>
LbxQueryExtension</emphasis>
.
</para>


<para>
The following requests are expected to be used only by the proxy, and are
instigated by the proxy: <emphasis>
LbxStartProxy</emphasis>
, <emphasis>
LbxStopProxy</emphasis>
, <emphasis>
LbxNewClient</emphasis>
, <emphasis>
LbxSwitch</emphasis>
, <emphasis>
LbxCloseClient</emphasis>
, <emphasis>
LbxModifySequence</emphasis>
, <emphasis>
LbxAllowMotion</emphasis>
, <emphasis>
LbxInvalidateTag</emphasis>
, <emphasis>
LbxTagData</emphasis>
 and <emphasis>
LbxQueryTag</emphasis>
.
</para>


<para>
All other requests are sent by the proxy to the LBX server and are instigated
by reception of an X request from the client. They replace the X request.
</para>


<sect3 id='requests_initiated_by_the_proxy_or_by_the_client'>
<title>Requests Initiated by the Proxy or by the Client</title>

<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxQueryVersion</entry>
    </row>
  </thead>
  <tbody>
    <row>
     <entry>=&gt;;</entry>
    </row>
    <row>
      <entry role='protoargs'>majorVersion: CARD16</entry>
    </row>
    <row>
      <entry role='protoargs'>minorVersion: CARD16</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request returns the major and minor version numbers of the LBX protocol.
</para>


<para>
The encoding of this request is on <ulink url="lbx.htm#34166">See
LbxQueryVersion</ulink>.
</para>



</sect3>
<sect3 id='requests_initiated_or_substituted_by_the_proxy'>
<title>Requests Initiated or Substituted by the Proxy</title>

<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxQueryExtension</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
nbytes</emphasis>
: CARD32</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
name</emphasis>
: STRING8</entry>
    </row>
    <row>
      <entry>=&gt;</entry>
    </row>
    <row>
      <entry role='protoargs'>num-requests: CARD8</entry>
    </row>
    <row>
      <entry role='protoargs'>present: BOOL</entry>
    </row>
    <row>
      <entry role='protoargs'>major-opcode: CARD8</entry>
    </row>
    <row>
      <entry role='protoargs'>first-event: CARD8</entry>
    </row>
    <row>
      <entry role='protoargs'>first-error: CARD8</entry>
    </row>
    <row>
      <entry role='protoargs'>reply-mask: LISTofMASK      /* optional */</entry>
    </row>
    <row>
      <entry role='protoargs'>event-mask:LISTofMASK      /* optional */</entry>
    </row>
    <row>
      <entry role='protoerror'>Errors: <emphasis>
Alloc</emphasis>
</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request is identical to the <emphasis>
QueryExtension</emphasis>
 request, with an additional field, and two optional additional fields. When
the client issues an <emphasis>
QueryExtension</emphasis>
 request, the proxy will substitute an <emphasis>
LbxQueryExtension</emphasis>
 request.
</para>


<para>
This request determines if the named extension is present. If so, the major
opcode for the extension is returned, if it has one. Otherwise, zero is
returned. Any minor opcode and the request formats are specific to the
extension. If the extension involves additional event types, the base event
type code is returned. Otherwise, zero is returned. The format of events is
specific to the extension. If the extension involves additional error codes,
the base error code is returned. Otherwise, zero is returned. The format of
additional data in the errors is specific to the extension.
</para>


<para>
In addition, the number of requests defined by the named extension is returned.
If the number of requests is nonzero, and if the information is available,
reply-mask and event-mask will be included in the reply. The reply-mask
represents a bit-wise one-to-one correspondence with the extension requests.
The least significant bit corresponds to the first request, and the next bit
corresponds to the next request, and so on. Each element in the list contains
eight meaningful bits, except for the last element, which contains eight or
fewer meaningful bits. Unused bits are not guaranteed to be zero. The bit
corresponding to a request is set if the request could generate a reply,
otherwise it is zero. In the same way, the event-mask represents a bit-wise
one-to-one correspondence with the extension requests. A bit is set if the
corresponding request could result in the generation of one or more extension
or X11 events. If reply-mask is present in the reply, event-mask will also be
present.
</para>


<para>
The encoding of this request is on <ulink url="lbx.htm#37117">See
LbxQueryExtension</ulink>.
</para>



</sect3>
<sect3 id='control_requests_initiated_by_the_proxy'>
<title>Control Requests Initiated by the Proxy</title>

<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxStartProxy</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
options</emphasis>
: LISTofOPTION</entry>
    </row>
    <row>
      <entry>=&gt;</entry>
    </row>
    <row>
      <entry role='protoargs'>choices: LISTofCHOICE</entry>
    </row>
    <row>
      <entry role='protoerror'>Errors: <emphasis>
LbxClient</emphasis>
, <emphasis>
Alloc</emphasis>
</entry>
    </row>
    <row>
      <entry>where:</entry>
    </row>
    <row>
      <entry role='protoargs'>OPTION       [optcode: CARD8,</entry>
    </row>
    <row>
      <entry role='protoargs'>      len: OPTLEN,</entry>
    </row>
    <row>
      <entry role='protoargs'>      option:       (See <ulink
url="lbx.htm#35444">See StartProxy Options</ulink>) ]</entry>
    </row>
    <row>
      <entry role='protoargs'>CHOICE      [optcode: CARD8,</entry>
    </row>
    <row>
      <entry role='protoargs'>      len: OPTLEN,</entry>
    </row>
    <row>
      <entry role='protoargs'>      choice:        (See <ulink
url="lbx.htm#35444">See StartProxy Options</ulink>) ]</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>
<!--
    <row>
      <entry role='protoargs'> -->


<table frame='topbot'>
 <title>StartProxy Options</title>
 <?dbfo keep-together="always" ?>
 <tgroup cols='4' align='left' colsep='0' rowsep='0'>
 <colspec colname='c1' colwidth='1.0*'/>
 <colspec colname='c2' colwidth='1.5*'/>
 <colspec colname='c3' colwidth='1.5*'/>
 <colspec colname='c4' colwidth='1.5*'/>
<thead>
<row rowsep='1'>
  <entry>optcode</entry>
  <entry>option</entry>
  <entry>choice</entry>
  <entry>default</entry>
</row>
</thead>
<tbody>
<row>
    <entry>delta-proxy</entry>
    <entry>DELTAOPT</entry>
    <entry>DELTACHOICE</entry>
    <entry>entries=16, maxlen=64</entry>
</row>
<row>
    <entry>delta-server</entry>
    <entry>DELTAOPT</entry>
    <entry>DELTACHOICE</entry>
    <entry>entries=16, maxlen=64</entry>
</row>
<row>
    <entry>stream-comp</entry>
    <entry>LISTofNAMEDOPT</entry>
    <entry>INDEXEDCHOICE</entry>
    <entry>No Compression</entry>
</row>
<row>
    <entry>bitmap-comp</entry>
    <entry>LISTofSTRING8</entry>
    <entry>LISTofINDEXEDOPT</entry>
    <entry>No Compression</entry>
</row>
<row>
    <entry>pixmap-comp</entry>
    <entry>LISTofPIXMAPMETHOD</entry>
    <entry>LISTofPIXMAPCHOICE</entry>
    <entry>No Compression</entry>
</row>
<row>
    <entry>use-squish</entry>
    <entry>BOOL</entry>
    <entry>BOOL</entry>
    <entry>True</entry>
</row>
<row>
    <entry>use-tags</entry>
    <entry>BOOL</entry>
    <entry>BOOL</entry>
    <entry>True</entry>
</row>
<row>
    <entry>colormap</entry>
    <entry>LISTofSTRING8</entry>
    <entry>INDEXEDCHOICE</entry>
    <entry>No Colormap Grabbing</entry>
</row>
<row>
    <entry>extension</entry>
    <entry>NAMEDOPT</entry>
    <entry>INDEXEDCHOICE</entry>
    <entry>Extension Disabled</entry>
  </row>
</tbody>
</tgroup>
</table>
<!--      </entry>
    </row>
-->
<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <tbody>
    <row>
      <entry role='protoargs'>&nbsp;</entry>
    </row>
    <row>
      <entry role='protoargs'>DELTAOPT       [minN, maxN, prefN: CARD8</entry>
    </row>
    <row>
      <entry role='protoargs'>      minMaxMsgLen, maxMaxMsgLen, prefMaxMsgLen:
CARD8]</entry>
    </row>
    <row>
      <entry role='protoargs'>DELTACHOICE      [entries, maxlen:
CARD8]</entry>
    </row>
    <row>
      <entry role='protoargs'>INDEXEDCHOICE      [index: CARD8,</entry>
    </row>
    <row>
      <entry role='protoargs'>      data: LISTofBYTE]</entry>
    </row>
    <row>
      <entry role='protoargs'>INDEXEDOPT      [index, opcode: CARD8]</entry>
    </row>
    <row>
      <entry role='protoargs'>NAMEDOPT      [name: STRING8,</entry>
    </row>
    <row>
      <entry role='protoargs'>      detail: LISTofBYTE]</entry>
    </row>
    <row>
      <entry role='protoargs'>OPTLEN      1 or 3 CARD8</entry>
    </row>
    <row>
      <entry role='protoargs'>      where:</entry>
    </row>
    <row>
      <entry role='protoargs'>      (0 &lt; in &lt;= 0xFF):       out =
in</entry>
    </row>
    <row>
      <entry role='protoargs'>      (0 &lt;= in&lt;= 0xFFFF):       out[0] =
0; out[1] = in &gt;&gt; 8; out[2] = in&amp; 0xFF;</entry>
    </row>
    <row>
      <entry role='protoargs'>PIXMAPMETHOD      [name: STRING8,</entry>
    </row>
    <row>
      <entry role='protoargs'>      format-mask: BITMASK,</entry>
    </row>
    <row>
      <entry role='protoargs'>      depths: LISTofCARD8]</entry>
    </row>
    <row>
      <entry role='protoargs'>PIXMAPCHOICE      [index, opcode: CARD8,</entry>
    </row>
    <row>
      <entry role='protoargs'>      format-mask: BITMASK,</entry>
    </row>
    <row>
      <entry role='protoargs'>      depths: LISTofCARD8]</entry>
    </row>
    <row>
      <entry role='protoargs'></entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request negotiates LBX protocol options, and switches the proxy-server
connection from X11 protocol to LBX protocol.
</para>


<para>
The proxy gives the preferred protocol options in the request. The server
chooses from the given options and informs the proxy which to use. The options
may be listed in any order, and the proxy may choose which options to
negotiate. If an option is not successfully negotiated, the default is used.
</para>


<para>
The server delta cache and proxy delta caches can be configured for number of
entries, and the length of entries. (See <ulink url="lbx.htm#22595">See Delta
cache</ulink> for details.) The delta caches are configured using the <emphasis>
delta-server</emphasis>
 and <emphasis>
delta-proxy</emphasis>
 options. To configure a cache, the proxy sends the minimum, maximum and
preferred values for the number of cache entries, (<emphasis>
minN, maxN, prefN</emphasis>
), and the length of the cache entries, (<emphasis>
minMaxMsgLen, maxMaxMsgLen, prefMaxMsgLen</emphasis>
). The server’s reply fields, <emphasis>
entries</emphasis>
 and <emphasis>
maxlen</emphasis>
, contains the values to use. These values must be within the ranges specified
by the proxy. The server may also specify an <emphasis>
entries</emphasis>
 value of 0 to disable delta caching. The cache entry lengths are specified in
units of 4 bytes.
</para>


<para>
The stream compression algorithm is selected using the <emphasis>
stream-comp </emphasis>
option. (Stream compression is described in <ulink url="lbx.htm#11596">See
Stream Compression</ulink>.) Each algorithm has a name that follows the naming
conventions in <ulink url="lbx.htm#13570">See Algorithm Naming</ulink>. To
negotiate using the stream-comp option, the proxy lists its available
compressors. For each candidate algorithm, the proxy sends the name in the
<emphasis>
name</emphasis>
 field, and uses the <emphasis>
detail</emphasis>
 field to send any additional data specific to each compression algorithm. The
reply contains a 0-based index into the list of algorithms to indicate which
algorithm to use, followed by data specific to that algorithm.
</para>


<para>
Bitmap compression is negotiated using the <emphasis>
bitmap-comp</emphasis>
 option. The proxy sends a list of names of available algorithms, and the
server reply lists the algorithms to use. For each bitmap algorithm in the
reply, a 0-based index into the list of algorithms indicates the algorithm, and
the <emphasis>
opcode</emphasis>
 field gives the value for use in requests. The algorithm names follow the
conventions in <ulink url="lbx.htm#13570">See Algorithm Naming</ulink>.
</para>


<para>
Pixmap compression is negotiated using the <emphasis>
pixmap-comp</emphasis>
 option. The proxy sends a list of available algorithms. For each algorithm,
the list includes, the name, a bitmask of supported formats, and a list of
depths that the format supports. The server reply lists the algorithms to use.
For each pixmap algorithm in the reply, the reply contains a 0-based index into
the list of proxy algorithms, the opcode to use in requests when referring to
this algorithm, a mask of valid formats, and a list of valid depths. Algorithm
names follow the conventions in <ulink url="lbx.htm#13570">See Algorithm
Naming</ulink>.
</para>


<para>
Squishing is negotiated using the use-squish option. If the proxy desires
squishing, it sends a true value. The reply from the server indicates whether
to do squishing, and will indicate squishing only if <emphasis>
use-squish</emphasis>
 is set to true in the request.
</para>


<para>
Tag caching, described in <ulink url="lbx.htm#11018">See Tags</ulink>, is
negotiated using the use-tag option. If the proxy desires tag caching, it sends
a true value. The reply from the server indicates whether to do tag caching,
and will demand caching only if <emphasis>
use-tag</emphasis>
 is set to true in the request.
</para>


<para>
The colormap option is used to negotiate what color matching algorithm will be
used by the proxy when the proxy uses the <emphasis>
LbxAllocColor</emphasis>
 request to allocate pixels in a grabbed colormap. To negotiate using the
colormap option, the proxy lists the names of available colormap algorithms.
The choice in the reply contains a 0-based index into the list of algorithms to
indicate which algorithm to use, followed by data specific to that algorithm.
If no colormap algorithm is successfully negotiated, then the <emphasis>
LbxAllocColor</emphasis>
, <emphasis>
LbxGrabCmap</emphasis>
, and <emphasis>
LbxReleaseCmap</emphasis>
 requests will not be used.
</para>


<para>
The extension option is used to control extensions to LBX. These extensions
may, for example, enable other types of compression. To negotiate an extension,
the name of the extension is sent, followed by any data specific to that
extension. The extension name follows the conventions in <ulink
url="lbx.htm#13570">See Algorithm Naming</ulink>. The extension option may
occur multiple times in the start proxy message, since multiple extensions can
be negotiated. The reply to an extension option contains the zero-based index
of the extension option, as counted in the <emphasis>
LbxStartProxy</emphasis>
 message. This index is followed by extension-specific information. The server
does not respond to extensions it does not recognize.
</para>


<para>
An <emphasis>
LbxClient</emphasis>
 error is returned when a client which is already communicating through an LBX
proxy to the X server sends a <emphasis>
LbxStartProxy</emphasis>
 request.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#27452">See
LbxStartProxy</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxStopProxy</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoerror'>Errors: <emphasis>
LbxClient</emphasis>
</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request terminates the connection between the proxy and X server, and
terminates any clients connected through the proxy.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#23471">See
LbxStopProxy</ulink>.
</para>


<para>
An <emphasis>
LbxClient</emphasis>
 error is returned if the requesting client is not an LBX proxy.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxNewClient</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
byte-order</emphasis>
: CARD8</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
client-id</emphasis>
: CARD32</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
protocol-major-version</emphasis>
: CARD16</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
protocol-minor-version:</emphasis>
 CARD16</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
authorization-protocol-name</emphasis>
: STRING8</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
authorization-protocol-data</emphasis>
: STRING8</entry>
    </row>
    <row>
      <entry>=&gt;</entry>
    </row>
    <row>
      <entry role='protoargs'>Core X reply (if connection is rejected)</entry>
    </row>
    <row>
      <entry role='protoargs'>&nbsp;</entry>
    </row>
    <row>
      <entry role='protoargs'>OR</entry>
    </row>
    <row>
      <entry role='protoargs'>&nbsp;</entry>
    </row>
    <row>
      <entry role='protoargs'>success: BOOL</entry>
    </row>
    <row>
      <entry role='protoargs'>change-type: {NoDeltas, NormalClientDeltas,
AppGroupDeltas}</entry>
    </row>
    <row>
      <entry role='protoargs'>protocol-major-version: CARD16</entry>
    </row>
    <row>
      <entry role='protoargs'>protocol-minor-version: CARD16</entry>
    </row>
    <row>
      <entry role='protoargs'>tag-id: CARD32</entry>
    </row>
    <row>
      <entry role='protoargs'>length: CARD16</entry>
    </row>
    <row>
      <entry role='protoargs'>connection-data: CONINFO or CONDIF or
CONDIFROOT</entry>
    </row>
    <row>
      <entry role='protoargs'>&nbsp;</entry>
    </row>
    <row>
      <entry role='protoargs'>where:</entry>
    </row>
    <row>
      <entry role='protoargs'>CONINFO:       (the &quot;additional data&quot;
portion of the core connection reply for successes)</entry>
    </row>
    <row>
      <entry role='protoargs'>CONDIF:      [resource-id-base: CARD32,</entry>
    </row>
    <row>
      <entry role='protoargs'>      root-input-masks: LISTofSETofEVENT]</entry>
    </row>
    <row>
      <entry role='protoargs'>CONDIFROOT:      [resource-id-base:
CARD32,</entry>
    </row>
    <row>
      <entry role='protoargs'>      root: WINDOW</entry>
    </row>
    <row>
      <entry role='protoargs'>      root-visual: VISUALID</entry>
    </row>
    <row>
      <entry role='protoargs'>      default-colormap: COLORMAP</entry>
    </row>
    <row>
      <entry role='protoargs'>      white-pixel, black-pixel: CARD32</entry>
    </row>
    <row>
      <entry role='protoargs'>      root-input-masks: LISTofSETofEVENT]</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
Errors: LbxClient, Alloc
</para>


<para>
This request, which is sent by the proxy over the control connection, creates a
new virtual connection to the server.
</para>


<para>
Much of the information in the <emphasis>
LbxNewClient</emphasis>
 request and reply is identical to the connection setup and reply information
in the core X protocol.
</para>


<para>
For the <emphasis>
LbxNewClient</emphasis>
 request, the field unique to LBX is client-id. For the <emphasis>
LbxNewClient</emphasis>
 reply, <emphasis>
tag-id</emphasis>
 and <emphasis>
change-type</emphasis>
 are fields unique to LBX, and the contents of connection-data may be different
in LBX from the core X protocol (see below).
</para>


<para>
The proxy assigns each virtual connection a unique identifier using the
<emphasis>
client-id</emphasis>
 field in the <emphasis>
LbxNewClient</emphasis>
 request. This client-id is used in the LBX protocol to specify the current
client (see the <emphasis>
LbxSwitch</emphasis>
 request and the <emphasis>
LbxSwitchEvent</emphasis>
). client-id 0 is reserved for the proxy control connection. An <emphasis>
LbxClient</emphasis>
 error will result if the <emphasis>
LbxNewClient</emphasis>
 request contains a client-id of 0 or an already in use client-id.
</para>


<para>
If the server rejects this new virtual connection, the server sends a core X
connection failure reply to the proxy. The current version of LBX does not
support the return of an <emphasis>
Authenticate</emphasis>
 reply.
</para>


<para>
If the <emphasis>
change-type</emphasis>
 field is set to <emphasis>
NoDeltas</emphasis>
, then <emphasis>
connection-data</emphasis>
 is sent using the CONINFO structure, which is identical to the additional data
of the core connection reply. If the <emphasis>
tag-id</emphasis>
 is non-zero, then the connection-data is stored by the proxy using this tag
value. Tagged connection data must be stored by the proxy, and can not be
invalidated by the proxy until an <emphasis>
LbxInvalidateTag</emphasis>
 event is received for that tag.
</para>


<para>
When the <emphasis>
change-type</emphasis>
 field is not set to <emphasis>
NoDeltas</emphasis>
, then connection data is sent as changes against connection information
previously sent to the proxy. The <emphasis>
tag-id</emphasis>
 field, if non-zero, has the tag of the previously sent data to apply the
changes to. A zero tag-id indicates that the changes are with respect to the
connection information sent when the proxy connected to the server.
</para>


<para>
If the <emphasis>
change-type</emphasis>
 field is set to <emphasis>
NormalClientDeltas</emphasis>
, then <emphasis>
connection-data</emphasis>
 is sent using the CONDIF structure. The values in the CONDIF structure are
substituted for the identically named fields of the connection information for
the new connection.
</para>


<para>
If the <emphasis>
change-type</emphasis>
 field is set to <emphasis>
AppGroupDeltas</emphasis>
, then <emphasis>
connection-data</emphasis>
 is sent using the CONDIFROOT structure. The <emphasis>
root</emphasis>
, <emphasis>
root-visual</emphasis>
, and <emphasis>
default-colormap</emphasis>
 fields, when nonzero, are substituted for the corresponding fields in the
reference connection information. The <emphasis>
white-pixel</emphasis>
 and <emphasis>
black-pixel</emphasis>
 fields are substituted only when the <emphasis>
default-colormap</emphasis>
 field of the reply is non-zero. When <emphasis>
default-colormap</emphasis>
 field of the reply is zero, so are <emphasis>
white-pixel</emphasis>
 and <emphasis>
black-pixel</emphasis>
. The first entry in the <emphasis>
root-input-masks</emphasis>
 field is the current-input-mask for the default root window. The remaining
entries in <emphasis>
root-input-masks</emphasis>
 are input masks for non-video screens, as defined by the X Print Extension.
The number of non-video screens is one less than the number of entries in
<emphasis>
root-input-masks</emphasis>
. These screens are at the end of screen list in the reference connection
information.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#15166">See The
description of this request is on page 13.</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxCloseClient</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
client</emphasis>
: CARD32</entry>
    </row>

    <row>
      <entry role='protoerror'>Errors: <emphasis>
LbxClient</emphasis>
</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This requests the server to close down the connection represented by the
specified proxy’s client identifier. If the specified client wasn’t
previously registered with the server by a <emphasis>
LbxNewClient</emphasis>
 request, the server will send the <emphasis>
LbxClient</emphasis>
 error.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#21121">See The
description of this request is on page 12.</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxSwitch</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
client</emphasis>
: CARD32</entry>
    </row>

    <row>
      <entry role='protoerror'>Errors: <emphasis>
LbxClient</emphasis>
</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request causes the X server to treat subsequent requests as being from a
connection to the X server represented by the specified client identifier.
</para>


<para>
If the client making the request is not the proxy, or if the client identifier
sent in the request was not previously sent in a <emphasis>
LbxNewClient</emphasis>
 request, an <emphasis>
LbxClient</emphasis>
 error is returned.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#36790">See
LbxSwitch</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxSync</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry>=&gt;</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
The sync request causes the server to send a reply when all requests before the
sync request have been processed.
</para>


<para>
The encoding for this client is on <ulink url="lbx.htm#21186">See
LbxSync</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxModifySequence</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
adjust</emphasis>
: CARD32</entry>
    </row>

    <row>
      <entry role='protoerror'>Errors: None</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request advances the sequence number of the virtual client connection by
the specified amount. The proxy sends the <emphasis>
LbxModifySequence</emphasis>
 request to the server when it replies to a client request without forwarding
the client request on to the X server.
</para>


<para>
The encoding for this client is on <ulink url="lbx.htm#10940">See The
description of this request is on page 13.</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxAllowMotion</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
num</emphasis>
: CARD32</entry>
    </row>

    <row>
      <entry role='protoerror'>Errors: None</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request controls the delivery of optional motion notify events, as
described in <ulink url="lbx.htm#15503">See Motion events</ulink>. The num
field specifies an increase in the allowed number of motion notify events sent.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#11897">See The
description of this request is on page 14.</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxInvalidateTag</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
tag</emphasis>
: CARD32</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
The LBX proxy sends this notification to the X server when it refuses to store
tagged data, or when it releases tagged data which was previously stored and
which was not invalidated by a notification from the X server.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#37545">See
LbxInvalidateTag</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxTagData</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
tag</emphasis>
: CARD32</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
real-length</emphasis>
: CARD32</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
data</emphasis>
: LISTofBYTE</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request specifies the data associated with a previously assigned tag. It
is sent in two circumstances: in response to receiving a <emphasis>
SendTagDataEvent</emphasis>
, and spontaneously, when the proxy must rely on the server to store data which
was not previously received from the server. The data is carried in the byte
order and structure as would have originally been sent in the core protocol
request.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#37174">See
LbxTagData</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxGrabCmap</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
cmap</emphasis>
: Colormap </entry>
    </row>
    <row>
      <entry>=&gt;</entry>
    </row>

    <row>
      <entry role='protoargs'><emphasis>
smart-grab</emphasis>
: BOOL</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
large-pixel: </emphasis>
BOOL      /* optional */</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
auto-release: </emphasis>
BOOL      /* optional */</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
three-channels</emphasis>
: BOOL      /* optional */</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
bits-per-rgb: </emphasis>
CARD4      /* optional */</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
cells</emphasis>
: LISTofCHAN      /* optional */</entry>
    </row>
    <row>
      <entry role='protoargs'>&nbsp;</entry>
    </row>
    <row>
      <entry role='protoargs'>where:</entry>
    </row>
    <row>
      <entry role='protoargs'>CHAN:      LISTofLBXPIXEL</entry>
    </row>
    <row>
      <entry role='protoargs'>LBXPIXEL:       PIXELPRIVATE or PIXELPRIVATERANGE
or </entry>
    </row>
    <row>
      <entry role='protoargs'>      PIXELALLOC or PIXELALLOCRANGE </entry>
    </row>
    <row>
      <entry role='protoargs'>PIXEL:      CARD8 or CARD16</entry>
    </row>
    <row>
      <entry role='protoargs'>PIXELPRIVATE:       [ pixel: PIXEL ]</entry>
    </row>
    <row>
      <entry role='protoargs'>PIXELPRIVATERANGE:       [ first-pixel,
last-pixel: PIXEL]</entry>
    </row>
    <row>
      <entry role='protoargs'>PIXELALLOC:       [ pixel: PIXEL,</entry>
    </row>
    <row>
      <entry role='protoargs'>      color: COLORSINGLE or COLORTRIPLE]</entry>
    </row>
    <row>
      <entry role='protoargs'>PIXELALLOCRANGE:       [ first-pixel,
last-pixel: PIXEL,</entry>
    </row>
    <row>
      <entry role='protoargs'>      colors: LISTofCOLORSINGLE or
LISTofCOLORTRIPLE]</entry>
    </row>
    <row>
      <entry role='protoargs'>COLORSINGLE:      [ value: CARD8 or CARD16
]</entry>
    </row>
    <row>
      <entry role='protoargs'>COLORTRIPLE:      [ r, g, b:
COLORSINGLE]</entry>
    </row>

    <row>
      <entry role='protoerror'>Errors: <emphasis>
Colormap</emphasis>
</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request asks the server for control of allocating new colormap cells in
the specified colormap. The server grants control by replying to this request.
If no changes have occurred since the last time this proxy grabbed this
colormap, then the <emphasis>
smart-grab</emphasis>
 field of the reply is set to true, and the optional fields are not sent.
Otherwise, the current contents of the colormap are placed in the reply, as
described later in this section.
</para>


<para>
Once the proxy has received the reply, it can use the <emphasis>
LbxAllocColor</emphasis>
 request to allocate new colormap cells without the performance penalty of
round trips. The proxy is still permitted to use the normal colormap and
<emphasis>
LbxIncrementPixel</emphasis>
 requests while the colormap is grabbed. The grab is valid across all virtual
connections of the proxy.
</para>


<para>
The <emphasis>
LbxGrabCmap</emphasis>
 request is limited to colormaps for the visual types negotiated as part of the
colormap algorithm negotiation in the start proxy request at connection setup.
</para>


<para>
The server and other proxies may not allocate new colormap cells in the
colormap while the colormap is grabbed by this proxy. If the server or another
proxy needs to allocate new colormap cells, the server sends a Lbx<emphasis>
ReleaseCmap</emphasis>
 event to the proxy holding the grab, which then issues an <emphasis>
LbxReleaseCmap</emphasis>
 request.
</para>


<para>
The server and other proxies may free colormap cells in a colormap grabbed by a
proxy. The server will send an <emphasis>
LbxFreeCells</emphasis>
 event to the proxy that currently has the colormap grabbed when the cell
reference count reaches 0.
</para>


<para>
If the colormap is a of a static visual type, such as <emphasis>
StaticGray</emphasis>
, <emphasis>
StaticColor</emphasis>
, <emphasis>
GrayScale</emphasis>
, or <emphasis>
TrueColor</emphasis>
, then the proxy’s grab is immediately released by the server, and the proxy
must use <emphasis>
LbxIncrementPixel</emphasis>
 requests in place of <emphasis>
LbxAllocColor</emphasis>
 requests for this colormap.
</para>


<para>
If the cmap field does not refer to a valid colormap or the colormap is already
grabbed by this proxy then a <emphasis>
Colormap</emphasis>
 error is generated.
</para>


<para>
The reply describes the contents of the colormap via several arguments and a
descriptive list containing one or three channels, with each channel describing
allocations in the colormap.
</para>


<para>
The <emphasis>
large-pixel</emphasis>
 argument, if True, specifies that PIXEL indices will be listed as CARD16
quantities instead of CARD8. The<emphasis>
 auto-release</emphasis>
 field, if True, indicates that this colormap is of a static visual type and
the proxy’s grab is immediately released by the server.
</para>


<para>
If <emphasis>
three-channels</emphasis>
 is False, a single channel is enclosed and color values are described using
COLORTRIPLE, which has fields for red, green and blue. A single channel is used
when the visual type is not <emphasis>
DirectColor</emphasis>
 or <emphasis>
TrueColor</emphasis>
.
</para>


<para>
If <emphasis>
three-channels</emphasis>
 is True, separate red, green and blue channel lists are enclosed, for
describing a <emphasis>
DirectColor</emphasis>
 or <emphasis>
TrueColor</emphasis>
 colormap. Color values for entries in each channel are sent using COLORSINGLE
and the corresponding PIXEL value refers to the RGB subfield of the current
channel, as defined by the corresponding red-mask, green-mask and blue-mask of
the visual.
</para>


<para>
The <emphasis>
bits-per-rgb</emphasis>
 value is one less than the bits-per-rgb-value field of the visual that the
colormap belongs to. If the value is 7 or less, then COLORSINGLE values in the
descriptive list are sent using CARD8 fields. Otherwise these values are sent
using CARD16 fields.
</para>


<para>
The list describing current colormap allocations contains entries of the
following types:
</para>


<para>
An LBXPIXELPRIVATE entry indicates that the pixel in the <emphasis>
pixel </emphasis>
field is unavailable for allocation.
</para>


<para>
An LBXPIXELPRIVATERANGE entry indicates that a contiguous range of pixels are
unavailable for allocation. The range is <emphasis>
first-pixel</emphasis>
 to <emphasis>
last-pixel</emphasis>
, and includes <emphasis>
last-pixel</emphasis>
.
</para>


<para>
An LBXPIXELALLOC entry indicates that the pixel in the <emphasis>
pixel </emphasis>
field is allocated as a read-only pixel. The <emphasis>
color</emphasis>
 field carries the color information of the pixel.
</para>


<para>
An LBXPIXELALLOCRANGE entry indicates that a contiguous range of pixels are
allocated as read-only. The range starts <emphasis>
first-pixel</emphasis>
 to <emphasis>
last-pixel</emphasis>
, and includes <emphasis>
last-pixel</emphasis>
. These fields are followed by a list of COLORSINGLE or COLORTRIPLE, depending
on the value of <emphasis>
three-channels</emphasis>
.
</para>


<para>
A NEXTCHANNEL entry indicates that the next channel of the colormap will be
described.
</para>


<para>
A LISTEND entry indicates the end of the colormap description.
</para>


<para>
All pixels not described in the reply are unallocated.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#17198">See
LbxGrabCmap</ulink>.
</para>



<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxReleaseCmap</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
cmap</emphasis>
: Colormap</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request releases the specified grabbed colormap. If the <emphasis>
cmap</emphasis>
 field does not refer to a colormap, a <emphasis>
BadColormap</emphasis>
 error is produced.
</para>


<para>
The proxy must remember the state of the colormap when the <emphasis>
LbxReleaseCmap</emphasis>
 request is issued if this proxy may at some future time issue another
<emphasis>
LbxGrabCmap</emphasis>
 request on this colormap before the state of the colormap changes.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#14796">See
LbxReleaseCmap</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxInternAtoms</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
count</emphasis>
: CARD16</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
names: LISTofSTRING8</emphasis>
</entry>
    </row>
    <row>
      <entry>=&gt;</entry>
    </row>

    <row>
      <entry role='protoargs'><emphasis>
atoms</emphasis>
: LISTofATOM</entry>
    </row>

    <row>
      <entry role='protoerror'>Errors: <emphasis>
Alloc</emphasis>
</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request allows the proxy to intern a group of atoms in a single round
trip. The server will create any atoms that do not exist.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#34140">See
LbxInternAtoms</ulink>.
</para>



</sect3>
<sect3 id='substitution_requests'>
<title>Substitution Requests</title>

<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxAllocColor</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
cmap</emphasis>
: Colormap</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
pixel</emphasis>
: CARD32</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
red</emphasis>
, <emphasis>
green</emphasis>
, <emphasis>
blue</emphasis>
: CARD16</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request is sent by a proxy that has given colormap grabbed to allocate a
new read-only cell in the colormap. The proxy may substitute this request for
the core <emphasis>
AllocColor</emphasis>
 and <emphasis>
AllocNamedColor</emphasis>
 requests.
</para>


<para>
The <emphasis>
pixel</emphasis>
 field identifies the colormap cell to allocate. The <emphasis>
red</emphasis>
, <emphasis>
green</emphasis>
, and <emphasis>
blue</emphasis>
 fields are the hardware specific color values of the corresponding fields of
the core <emphasis>
AllocColor</emphasis>
 request. The mapping to hardware specific colormap values by the proxy is
performed using the color algorithm negotiated by <emphasis>
LbxStartProxy</emphasis>
.
</para>


<para>
For colormaps of static visual types, the <emphasis>
LbxIncrementPixel</emphasis>
 request is used instead of LBX <emphasis>
AllocColor</emphasis>
.
</para>


<para>
If the <emphasis>
cmap</emphasis>
 field does not identify a grabbed colormap then a <emphasis>
BadAccess</emphasis>
 error is produced. If the <emphasis>
pixel</emphasis>
 field refers to a read-write entry, or the pixel field refers to a pixel
outside of the range of this colormap, a <emphasis>
BadAlloc</emphasis>
 error is produced.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#28429">See
LbxAllocColor</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxIncrementPixel</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
cmap</emphasis>
: COLORMAP</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
pixel</emphasis>
: CARD32</entry>
    </row>

    <row>
      <entry role='protoerror'>Errors: None</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request replaces the <emphasis>
AllocColor</emphasis>
 request for read-only pixels currently allocated for the current client. If
the visual type of the colormap is of a static type, this request may be used
on currently unallocated pixels. The colormap is not required to be grabbed to
use this request.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#38053">See The
description of this request is on page 14.</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxDelta</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
count</emphasis>
: CARD8</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
cache-index</emphasis>
: CARD8</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
diffs</emphasis>
: LISTofDIFFITEM</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request contains a minimal amount of information relative to a similar
prior request. The information is in the form of a difference comparison to a
prior request. The prior request is specified by an index to a cache,
independently maintained by both the proxy and the server.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#39838">See The
description of this request is on page 18.</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxGetModifierMapping</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry>=&gt;</entry>
    </row>

    <row>
      <entry role='protoargs'><emphasis>
keyspermod</emphasis>
: CARD8</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
tag</emphasis>
: CARD32</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
keycodes</emphasis>
: LISTofKEYCODE             /* optional */</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request is identical to the core <emphasis>
GetModifierMapping</emphasis>
 request, with the addition of a tag being returned in the reply. See <ulink
url="lbx.htm#26534">See Tag Substitution in Requests</ulink> for a description
of the <emphasis>
tag</emphasis>
 field and optional fields.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#40057">See
LbxGetModifierMapping</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxGetKeyboardMapping</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
firstKeyCode</emphasis>
: KEYCODE</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
count</emphasis>
: CARD8</entry>
    </row>
    <row>
      <entry>=&gt;</entry>
    </row>

    <row>
      <entry role='protoargs'><emphasis>
keysperkeycode</emphasis>
: CARD8</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
tag</emphasis>
: CARD32</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
keysyms</emphasis>
: LISTofKEYSYM      /* optional */</entry>
    </row>

    <row>
      <entry role='protoerror'>Errors: <emphasis>
Value</emphasis>
</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request is identical to the X <emphasis>
GetKeyboardMapping</emphasis>
 protocol request, with the addition that a tag is returned in the reply. See
<ulink url="lbx.htm#26534">See Tag Substitution in Requests</ulink> for a
description of the <emphasis>
tag</emphasis>
 field and optional fields.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#21702">See
LbxGetKeyboardMapping</ulink>.
</para>



<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxGetWinAttrAndGeom</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
window</emphasis>
: WINDOW</entry>
    </row>
    <row>
      <entry>=&gt;</entry>
    </row>

    <row>
      <entry role='protoargs'>visual: VISUALID</entry>
    </row>
    <row>
      <entry role='protoargs'>class: {InputOutput, InputOnly}</entry>
    </row>
    <row>
      <entry role='protoargs'>bit-gravity: BITGRAVITY</entry>
    </row>
    <row>
      <entry role='protoargs'>win-gravity: WINGRAVITY</entry>
    </row>
    <row>
      <entry role='protoargs'>backing-store: {NotUseful, WhenMapped,
Always}</entry>
    </row>
    <row>
      <entry role='protoargs'>backing-planes: CARD32</entry>
    </row>
    <row>
      <entry role='protoargs'>backing-pixel: CARD32</entry>
    </row>
    <row>
      <entry role='protoargs'>save-under: BOOL</entry>
    </row>
    <row>
      <entry role='protoargs'>colormap: COLORMAP or None</entry>
    </row>
    <row>
      <entry role='protoargs'>map-is-installed: BOOL</entry>
    </row>
    <row>
      <entry role='protoargs'>map-state: {Unmapped, Unviewable,
Viewable}</entry>
    </row>
    <row>
      <entry role='protoargs'>all-event-masks, your-event-mask:
SETofEVENT</entry>
    </row>
    <row>
      <entry role='protoargs'>do-not-propagate-mask: SETofDEVICEEVENT</entry>
    </row>
    <row>
      <entry role='protoargs'>override-redirect: BOOL</entry>
    </row>
    <row>
      <entry role='protoargs'>root: WINDOW</entry>
    </row>
    <row>
      <entry role='protoargs'>depth: CARD8</entry>
    </row>
    <row>
      <entry role='protoargs'>x, y: INT16</entry>
    </row>
    <row>
      <entry role='protoargs'>width, height, border-width: CARD16</entry>
    </row>

    <row>
      <entry role='protoerror'>Errors: <emphasis>
Window</emphasis>
</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
<emphasis>
GetWindowAttributes</emphasis>
 and <emphasis>
GetGeometry</emphasis>
 are frequently used together in the X protocol. <emphasis>
LbxGetWinAttrAndGeom</emphasis>
 allows the proxy to request the same information in one round trip.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#41440">See
LbxGetWinAttrAndGeom</ulink>.
</para>



<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxQueryFont</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
font</emphasis>
: FONTABLE</entry>
    </row>
    <row>
      <entry>=&gt;</entry>
    </row>
    <row>
      <entry role='protoargs'>compression: BOOL</entry>
    </row>
    <row>
      <entry role='protoargs'>tag: CARD32</entry>
    </row>
    <row>
      <entry role='protoargs'>font-info: FONTINFO                  /* optional
*/</entry>
    </row>
    <row>
      <entry role='protoargs'>char-infos: LISTofCHARINFO or LISTofLBXCHARINFO
               /* optional */</entry>
    </row>
    <row>
      <entry role='protoargs'>where:</entry>
    </row>
    <row>
      <entry role='protoargs'>LBXCHARINFO:       [left-side-bearing:
INT6</entry>
    </row>
    <row>
      <entry role='protoargs'>      right-side-bearing: INT7</entry>
    </row>
    <row>
      <entry role='protoargs'>      character-width: INT6</entry>
    </row>
    <row>
      <entry role='protoargs'>      ascent: INT6</entry>
    </row>
    <row>
      <entry role='protoargs'>      descent: INT7]</entry>
    </row>

    <row>
      <entry role='protoerror'>Errors: <emphasis>
Font,Alloc</emphasis>
      </entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request is used to replace the core <emphasis>
QueryFont</emphasis>
 request and has identical semantics.
</para>


<para>
See <ulink url="lbx.htm#26534">See Tag Substitution in Requests</ulink> for a
description of the <emphasis>
tag</emphasis>
 field and optional fields.
</para>


<para>
The <emphasis>
compression</emphasis>
 field is True if the <emphasis>
char-infos</emphasis>
 field is represented using LBXCHARINFO.
</para>


<para>
The per-character information will be encoded in an LBXCHARINFO when, for every
character, the character-width, left-side-bearing, and ascent can each be
represented in not more than 6 bits, and the right-side-bearing and descent can
each be represented in not more than 7 bits, and the attributes field is
identical the attributes field of the max_bounds of the <emphasis>
font_info</emphasis>
 field of the font.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#24597">See
LbxQueryFont</ulink>.
</para>



<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxChangeProperty</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
window</emphasis>
: WINDOW</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
property</emphasis>
: ATOM</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
type</emphasis>
: ATOM</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
format</emphasis>
: {0,8,16,32}</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
mode</emphasis>
: {Replace, Prepend, Append}</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
nUnits</emphasis>
: CARD32</entry>
    </row>
    <row>
      <entry>=&gt;</entry>
    </row>
    <row>
      <entry role='protoargs'>tag: CARD32</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request is sent to the server when the client sends an X <emphasis>
ChangeProperty </emphasis>
request through the proxy. The size of the data is sent with this request, but
not the property data itself. The server reply contains a tag identifier for
the data, which is stored in the proxy. The proxy must not discard this data
before it is sent to the server, or invalidated by the server. This means that
before issuing an <emphasis>
LbxStopProxy</emphasis>
 request, or exiting, the proxy must send Lbx<emphasis>
TagData</emphasis>
 requests for these items. If the server loses the connection before the
information is sent back, the server should revert the property value to its
last known value, if possible.
</para>


<para>
If the <emphasis>
mode</emphasis>
 field is <emphasis>
Prepend</emphasis>
 or <emphasis>
Append</emphasis>
, the tag refers only to the prepended or appended data.
</para>


<para>
If the tag in the reply is zero, then the change was ignored by the server, as
defined in the security extension. The proxy should dump the associated data,
since the server will never ask for it.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#18013">See
LbxChangeProperty</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxGetProperty</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
window</emphasis>
: WINDOW</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
property</emphasis>
: ATOM</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
type</emphasis>
: ATOM or AnyPropertyType</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
long-offset</emphasis>
: CARD32</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
long-length</emphasis>
: CARD32</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
delete</emphasis>
: CARD8</entry>
    </row>
    <row>
      <entry>=&gt;</entry>
    </row>

    <row>
      <entry role='protoargs'>type: ATOM or None</entry>
    </row>
    <row>
      <entry role='protoargs'>format: {0, 8, 16, 32}</entry>
    </row>
    <row>
      <entry role='protoargs'>bytes-after: CARD32</entry>
    </row>
    <row>
      <entry role='protoargs'>nItems: CARD32</entry>
    </row>
    <row>
      <entry role='protoargs'>tag: CARD32</entry>
    </row>
    <row>
      <entry role='protoargs'>value: LISTofINT8 or LISTofINT16 or
LISTofINT32</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request may be used by the proxy as a substitution for a core <emphasis>
GetProperty</emphasis>
 request. It allows tags to be used for property data that is unlikely to
change often in value, but is likely to be fetched by multiple clients.
</para>


<para>
The <emphasis>
LbxGetProperty</emphasis>
 request has the same arguments as the core <emphasis>
GetProperty</emphasis>
 request. The reply for <emphasis>
LbxGetProperty</emphasis>
 has all of the fields from the core <emphasis>
GetProperty</emphasis>
 reply, but has the additional fields of <emphasis>
nItems</emphasis>
 and <emphasis>
tag</emphasis>
.
</para>


<para>
In order to utilize tags in <emphasis>
LbxGetProperty</emphasis>
 for a specific property, the server must first send the complete property data
to the proxy and associate this data with a tag. More precisely, the server
sends an <emphasis>
LbxGetProperty</emphasis>
 reply with a new <emphasis>
tag</emphasis>
, <emphasis>
nItems</emphasis>
 set to the number of items in the property, the size of the property data in
the reply length field, and the complete property data in value. The proxy
stores the property data in its tag cache and associates it with the specified
tag.
</para>


<para>
In response to future <emphasis>
LbxGetProperty</emphasis>
 requests for the same property, if the server thinks that the proxy has the
actual property data in its tag cache, it may choose to send an <emphasis>
LbxGetProperty</emphasis>
 reply without the actual property data. In this case, the reply would include
a non-zero <emphasis>
tag</emphasis>
, a zero reply length, and no data for value.
</para>


<para>
If the server chooses not to generate a tagged reply to <emphasis>
LbxGetProperty</emphasis>
, or for some reason is unable to do so, it would send a reply with a <emphasis>
tag</emphasis>
 of zero, the size of the property data in the reply length field, and the
complete property data in value.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#13863">See
LbxGetProperty</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxPolyPoint</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
gc-and-drawable: </emphasis>
LBXGCANDDRAWABLE</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
points</emphasis>
: LISTofLBXPOINT</entry>
    </row>

    <row>
      <entry role='protoerror'>Errors: <emphasis>
Alloc</emphasis>
 and those given for the corresponding X request.</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request replaces the <emphasis>
PolyPoint</emphasis>
 request. Not all <emphasis>
PolyPoint</emphasis>
 requests can be represented as <emphasis>
LbxPolyPoint</emphasis>
 requests.
</para>


<para>
The proxy will convert the representation of the points to be relative to the
previous point, as described by previous coordinate mode in the X protocol.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#29719">See
LbxPolyPoint</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxPolyLine</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
gc-and-drawable: </emphasis>
LBXGCANDDRAWABLE</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
points</emphasis>
: LISTofLBXPOINT</entry>
    </row>

    <row>
      <entry role='protoerror'>Errors: <emphasis>
Alloc</emphasis>
 and those given for the corresponding X request.</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request replaces the <emphasis>
PolyLine</emphasis>
 request. Not all <emphasis>
PolyLine</emphasis>
 requests can be represented as <emphasis>
LbxPolyline</emphasis>
 requests.
</para>


<para>
The proxy will convert the representation of the points to be relative to the
previous point, as described by previous coordinate mode in the X protocol.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#31086">See The
description of this request is on page 21.</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxPolySegment</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
gc-and-drawable: </emphasis>
LBXGCANDDRAWABLE</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
segments</emphasis>
: LISTofLBXSEGMENT</entry>
    </row>
    <row>
      <entry role='protoargs'>&nbsp;</entry>
    </row>
    <row>
      <entry role='protoargs'>where:</entry>
    </row>
    <row>
      <entry role='protoargs'>LBXSEGEMENT; [x1, y1, x2, y2: LBXINT16]</entry>
    </row>

    <row>
      <entry role='protoerror'>Errors: <emphasis>
Alloc</emphasis>
 and those given for the corresponding X request.</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request replaces the <emphasis>
PolySegment</emphasis>
 request. Not all <emphasis>
PolySegment</emphasis>
 requests can be represented as <emphasis>
LbxPolySegment</emphasis>
 requests.
</para>


<para>
For segments other than the first segment of the request, [x1, y1] is
relative to [x1, y1] of the previous segment. For all segments, [x2, y2] is
relative to that segment’s [x1, y1].
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#27528">See
LbxPolySegment</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxPolyRectangle</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
gc-and-drawable: </emphasis>
LBXGCANDDRAWABLE</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
rectangles</emphasis>
: LISTofLBXRECTANGLE</entry>
    </row>

    <row>
      <entry role='protoerror'>Errors: <emphasis>
Alloc</emphasis>
 and those given for the corresponding X request.</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request replaces the <emphasis>
PolyRectangle</emphasis>
 request. Not all <emphasis>
PolyRectangle</emphasis>
 requests can be represented as <emphasis>
LbxPolyRectangle</emphasis>
 requests.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#33628">See The
description of this request is on page 22.</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxPolyArc</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
gc-and-drawable: </emphasis>
LBXGCANDDRAWABLE</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
arcs</emphasis>
: LISTofLBXARC</entry>
    </row>

    <row>
      <entry role='protoerror'>Errors: <emphasis>
Alloc</emphasis>
 and those given for the corresponding X request.</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request replaces the <emphasis>
PolyArc</emphasis>
 request. Not all <emphasis>
PolyArc</emphasis>
 requests can be represented as <emphasis>
LbxPolyArc</emphasis>
 requests.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#25855">See
LbxPolyArc</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxPolyFillRectangle</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
gc-and-drawable: </emphasis>
LBXGCANDDRAWABLE</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
rectangles</emphasis>
: LISTofLBXRECTANGLE</entry>
    </row>

    <row>
      <entry role='protoerror'>Errors: <emphasis>
Alloc</emphasis>
 and those given for the corresponding X request.</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request replaces the <emphasis>
PolyFillRectangle</emphasis>
 request. Not all <emphasis>
PolyFillRectangle</emphasis>
 requests can be represented as <emphasis>
LbxPolyFillRectangle</emphasis>
 requests.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#26399">See
LbxPolyFillRectangle</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxPolyFillArc</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
gc-and-drawable: </emphasis>
LBXGCANDDRAWABLE</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
arcs</emphasis>
: LISTofLBXARC</entry>
    </row>

    <row>
      <entry role='protoerror'>Errors: <emphasis>
Alloc</emphasis>
 and those given for the corresponding X request.</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request replaces the <emphasis>
PolyFillArc</emphasis>
 request. Not all <emphasis>
PolyFillArc</emphasis>
 requests can be represented as <emphasis>
LbxPolyFillArc</emphasis>
 requests.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#19081">See The
description of this request is on page 22.</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxFillPoly</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
gc-and-drawable: </emphasis>
LBXGCANDDRAWABLE</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
shape</emphasis>
: BYTE</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
points</emphasis>
: LISTofLBXPOINT</entry>
    </row>

    <row>
      <entry role='protoerror'>Errors: <emphasis>
Alloc</emphasis>
 and those given for the corresponding X request.</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request replaces the <emphasis>
FillPoly</emphasis>
 request. Not all <emphasis>
FillPoly</emphasis>
 requests can be represented as <emphasis>
LbxFillPoly</emphasis>
 requests.
</para>


<para>
The proxy will convert the representation of the points to be relative to the
previous point, as described by previous coordinate mode in the X protocol.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#24998">See
LbxFillPoly</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxCopyArea</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
srcCache</emphasis>
: CARD8      /* source drawable */</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
gc-and-drawable: </emphasis>
LBXGCANDDRAWABLE</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
src-Drawable</emphasis>
: CARD32</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
src-x</emphasis>
: LBXPINT16</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
src-y</emphasis>
: LBXPINT16</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
width</emphasis>
: LBXCARD16</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
height</emphasis>
: LBXCARD16</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
dst-x</emphasis>
: LBXPINT16 </entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
dst-y</emphasis>
: LBXPINT16</entry>
    </row>

    <row>
      <entry role='protoerror'>Errors: Those given for the corresponding X
request.</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request replaces the <emphasis>
CopyArea</emphasis>
 request for requests within its encoding range.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#10231">See
LbxCopyArea</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxCopyPlane</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
bit-plane</emphasis>
: CARD32</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
src-cache</emphasis>
: CARD8      /* cache reference for source drawable */</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
gc-and-drawable: </emphasis>
LBXGCANDDRAWABLE</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
src-drawable</emphasis>
: CARD32</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
src-x</emphasis>
: LBXPINT16</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
src-y</emphasis>
: LBXPINT16</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
width</emphasis>
: LBXCARD16</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
height</emphasis>
: LBXCARD16</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
dst-x</emphasis>
: LBXPINT16</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
dst-y</emphasis>
: LBXPINT16</entry>
    </row>

    <row>
      <entry role='protoerror'>Errors: Those given for the corresponding X
request.</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request replaces the <emphasis>
CopyPlane</emphasis>
 request for requests within its coding range.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#18847">See
LbxCopyPlane</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxPolyText8</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
gc-and-drawable: </emphasis>
LBXGCANDDRAWABLE</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
x</emphasis>
: LBXPINT16</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
y</emphasis>
: LBXPINT16</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
items</emphasis>
: LISTofTEXTITEM8</entry>
    </row>

    <row>
      <entry role='protoerror'>Errors: <emphasis>
Alloc</emphasis>
, and those given for the corresponding X request.</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request replaces the <emphasis>
PolyText8</emphasis>
 request for requests within its encoding range.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#39640">See The
description of this request is on page 23.</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxPolyText16</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
gc-and-drawable: </emphasis>
LBXGCANDDRAWABLE</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
x:</emphasis>
 LBXPINT16</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
y</emphasis>
: LBXPINT16</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
items</emphasis>
: LISTofTEXTITEM16</entry>
    </row>

    <row>
      <entry role='protoerror'>Errors: <emphasis>
Alloc</emphasis>
, and those given for the corresponding X request.</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request replaces the <emphasis>
PolyText16</emphasis>
 request for requests within its encoding range.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#32634">See The
description of this request is on page 24.</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxImageText8</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
gc-and-drawable: </emphasis>
LBXGCANDDRAWABLE</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
nChars</emphasis>
: CARD8</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
x</emphasis>
: LBXPINT16</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
y</emphasis>
: LBXPINT16</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
string</emphasis>
: STRING8</entry>
    </row>

    <row>
      <entry role='protoerror'>Errors: <emphasis>
Alloc</emphasis>
, and those given for the corresponding X request.</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request replaces the <emphasis>
ImageText8</emphasis>
 request for requests within its encoding range.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#17018">See The
description of this request is on page 24.</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxImageText16</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
nChars</emphasis>
: CARD8</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
gc-and-drawable: </emphasis>
LBXGCANDDRAWABLE</entry>
    </row>
    <row>
      <entry role='protoargs'>x: LBXPINT16</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
y</emphasis>
: LBXPINT16</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
string</emphasis>
: STRING16</entry>
    </row>

    <row>
      <entry role='protoerror'>Errors: <emphasis>
Alloc</emphasis>
, and those given for the corresponding X request.</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request replaces the <emphasis>
ImageText16</emphasis>
 request for requests within its encoding range.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#23910">See The
description of this request is on page 24.</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxPutImage</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
compression-method</emphasis>
: CARD8</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
format</emphasis>
: {<emphasis>
Bitmap</emphasis>
, <emphasis>
XYPixmap</emphasis>
, <emphasis>
ZPixmap</emphasis>
}                  /* packed */</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
gc-and-drawable: </emphasis>
LBXGCANDDRAWABLE</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
width</emphasis>
, <emphasis>
height</emphasis>
: LBXCARD16</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
dst-x</emphasis>
, <emphasis>
dst-y</emphasis>
: LBXPINT16</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
depth</emphasis>
: CARD8                  /* packed */</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
left-pad</emphasis>
: CARD8                  /* packed */</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
pad-bytes</emphasis>
: CARD8                  /* packed */</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
data</emphasis>
:LISTofBYTE</entry>
    </row>

    <row>
      <entry role='protoerror'>Errors: <emphasis>
Alloc</emphasis>
, <emphasis>
Value</emphasis>
</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
When the request can be usefully compressed, this request replaces the
<emphasis>
PutImage</emphasis>
 request. The <emphasis>
compression-method</emphasis>
 parameter contains the opcode of a compression method returned in the
<emphasis>
LbxStartProxy</emphasis>
 reply. The <emphasis>
pad-bytes</emphasis>
 parameter gives the number of unused pad bytes that follow the compressed
image data. All other parameters are as in the X request. If the specified
compression method is not recognized, the server returns a <emphasis>
Value</emphasis>
 error.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#12268">See
LbxPutImage</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxGetImage</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
drawable</emphasis>
: DRAWABLE</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
x</emphasis>
, <emphasis>
y</emphasis>
: INT16</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
width</emphasis>
, <emphasis>
height</emphasis>
: CARD16</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
plane-mask</emphasis>
: CARD32</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
format</emphasis>
: {XYPixmap, ZPixmap}</entry>
    </row>
    <row>
      <entry>=&gt;</entry>
    </row>
    <row>
      <entry role='protoargs'>depth: CARD8</entry>
    </row>
    <row>
      <entry role='protoargs'>x-length: CARD32</entry>
    </row>
    <row>
      <entry role='protoargs'>visual: VISUALID or None</entry>
    </row>
    <row>
      <entry role='protoargs'>compression-method: CARD8</entry>
    </row>
    <row>
      <entry role='protoargs'>data: LISTofBYTE</entry>
    </row>

    <row>
      <entry role='protoerror'>Errors: <emphasis>
Alloc,Match,Value</emphasis>
</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request can replace the <emphasis>
GetImage</emphasis>
 request. The same semantics apply, with the following exceptions.
</para>


<para>
The <emphasis>
compression-method</emphasis>
 field contains the opcode of the compression method used in the reply. The
compression opcodes are supplied in the <emphasis>
LbxStartProxy</emphasis>
 reply. The <emphasis>
x-length </emphasis>
field<emphasis>
 </emphasis>
contains the length of the uncompressed version of the reply in 4 byte units.
</para>


<para>
A <emphasis>
Value</emphasis>
 error is returned if the format is not recognized by the X server. A <emphasis>
Match</emphasis>
 error is returned under the same circumstances as described by the <emphasis>
GetImage</emphasis>
 request.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#10066">See
LbxGetImage</ulink>.
</para>



<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxBeginLargeRequest</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
large-request-length</emphasis>
: CARD32</entry>
    </row>

    <row>
      <entry role='protoerror'>Errors: <emphasis>
Alloc</emphasis>
</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request, along with the Lbx<emphasis>
LargeRequestData</emphasis>
 and Lbx<emphasis>
EndLargeRequest</emphasis>
 requests, is used to transport a large request in pieces. The smaller size of
the resulting requests allows smoother multiplexing of clients on a single low
bandwidth connection to the server. The resulting finer-grained multiplexing
improves responsiveness for the other clients.
</para>


<para>
After a <emphasis>
LbxBeginLargeRequest</emphasis>
 request is sent, multiple <emphasis>
LbxLargeRequestData</emphasis>
 requests are sent to transport all of the data in the large request, and
finally an <emphasis>
LbxEndLargeRequest</emphasis>
 request is sent. The large-request-length field expresses the total length of
the transported large request, expressed as the number of bytes in the
transported request divided by four.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#22013">See The
description of this request is on page 25.</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxLargeRequestData</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
data</emphasis>
: LISTofBYTE</entry>
    </row>

    <row>
      <entry role='protoerror'>Errors: <emphasis>
Alloc</emphasis>
</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This request is used to carry the segments of a larger request, as described in
the definition of <emphasis>
LbxBeginLargeRequest</emphasis>
. The data must be carried in order, starting with the request header, and each
segment must be multiples of 4 bytes long. If the <emphasis>
LbxLargeRequestData</emphasis>
 is not preceded by a corresponding <emphasis>
LbxBeginLargeRequest</emphasis>
, a <emphasis>
BadAlloc</emphasis>
 error is generated.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#31469">See The
description of this request is on page 26.</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxEndLargeRequest</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoerror'>Errors: <emphasis>
Length, Alloc</emphasis>
</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
As described in the definition of <emphasis>
LbxBeginLargeRequest</emphasis>
, <emphasis>
LbxEndLargeRequest</emphasis>
 is used to signal the end of a series of <emphasis>
LargeRequestData</emphasis>
 requests. If the total length of the data transported by the <emphasis>
LbxLargeRequestData</emphasis>
 requests does not match the large-request-length field of the preceding
<emphasis>
LbxBeginLargeRequest</emphasis>
 request, then a <emphasis>
Length</emphasis>
 error occurs. If the <emphasis>
LbxEndLargeRequest</emphasis>
 is not preceded by a corresponding <emphasis>
LbxBeginLargeRequest</emphasis>
, a <emphasis>
BadAlloc</emphasis>
 error is generated. The request is executed in order for that client as if it
were the request after the request preceding <emphasis>
LbxEndLargeRequest</emphasis>
.
</para>


<para>
The encoding for this request is on <ulink url="lbx.htm#31037">See
LbxEndLargeRequest</ulink>.
</para>



</sect3>
</sect2>
<sect2 id='events'>
<title>Events</title>

<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxSwitchEvent</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
client</emphasis>
: CARD32</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
Notify the proxy that the subsequent replies, events, and errors are relative
to the specified client.
</para>


<para>
The encoding for this event is on <ulink url="lbx.htm#17348">See
LbxSwitchEvent</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxCloseEvent</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
client</emphasis>
: CARD32</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
Notify the proxy that the specified client's connection to the server is closed.
</para>


<para>
The encoding for this event is on <ulink url="lbx.htm#41814">See The
description of this event is on page 27.</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxInvalidateTagEvent</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
tag</emphasis>
: CARD32</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
tag-type</emphasis>
: {Modmap, Keymap, Property, Font, ConnInfo}</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This message informs the proxy that the tag and the server data referenced by
the tag are obsolete, and should be discarded. The tag type may be one of the
following values: <emphasis>
LbxTagTypeModmap</emphasis>
, <emphasis>
LbxTagTypeKeymap</emphasis>
, <emphasis>
LbxTagTypeProperty</emphasis>
, <emphasis>
LbxTagTypeFont</emphasis>
, <emphasis>
LbxTagTypeConnInfo</emphasis>
.
</para>


<para>
The encoding for this event is on <ulink url="lbx.htm#34406">See
LbxInvalidateTagEvent</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxSendTagDataEvent</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
tag</emphasis>
: CARD32</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
tag-type</emphasis>
: {Property}</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
The server sends this event to the proxy to request a copy of tagged data which
is being stored by the proxy. The request contains a tag which was previously
assigned to the data by the server. The proxy should respond to <emphasis>
SendTagData</emphasis>
 by sending a <emphasis>
TagData</emphasis>
 request to the server. The tag type may be one of the following values:
<emphasis>
LbxTagTypeProperty</emphasis>
.
</para>


<para>
The encoding for this event is on <ulink url="lbx.htm#22353">See
LbxSendTagDataEvent</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxListenToOne</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
client</emphasis>
: CARD32 or <emphasis>
0xffffffff</emphasis>
</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
When the server is grabbed, <emphasis>
ListenToOne</emphasis>
 is sent to the proxy. As an X client, the proxy itself is unaffected by grabs,
in order that it may respond to requests for data from the X server.
</para>


<para>
When the client grabbing the server is managed through the proxy, the proxy
will permit messages from itself and the grabbing client to be sent immediately
to the server, and may buffer requests from other clients of the proxy. The
client is identified in the event.
</para>


<para>
When the client grabbing the server is not managed through the proxy, the
client field in the event will be <emphasis>
0xffffffff</emphasis>
. The proxy will communicate with the server, and it may buffer requests from
other clients. The proxy will continue to handle new connections while the
server is grabbed.
</para>


<para>
The server will send <emphasis>
ListenToAll</emphasis>
 to the proxy when the server is ungrabbed. There is no time-out for this
interval in the protocol.
</para>


<para>
The encoding for this event is on <ulink url="lbx.htm#18630">See The
description of this event is on page 27.</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <tbody>
    <row>
      <entry role='protoname'>LbxListenToAll</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
Notify the proxy that the server has been ungrabbed, and that the proxy may now
send all buffered client requests on to the server.
</para>


<para>
The encoding for this event is on <ulink url="lbx.htm#30610">See The
description of this event is on page 27.</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxQuickMotionDeltaEvent</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
deltaTime</emphasis>
: CARD8</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
deltaX</emphasis>
: INT8</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
deltaY</emphasis>
: INT8</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This event is used as a replacement for the <emphasis>
MotionNotify</emphasis>
 event when possible. The fields are used as deltas to the most recent
<emphasis>
MotionNotify</emphasis>
 event encoded as a <emphasis>
MotionNotify</emphasis>
 event, <emphasis>
LbxQuickMotionDeltaEvent</emphasis>
, or <emphasis>
LbxMotionDeltaEvent</emphasis>
. Not every <emphasis>
MotionNotify</emphasis>
 event can be encoded as a <emphasis>
LbxQuickMotionDeltaEvent</emphasis>
.
</para>


<para>
The encoding for this event is on <ulink url="lbx.htm#35213">See
LbxQuickMotionDeltaEvent</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxMotionDeltaEvent</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
deltaX</emphasis>
: INT8</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
deltaY</emphasis>
: INT8</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
deltaTime</emphasis>
: CARD16</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
deltaSequence</emphasis>
: CARD16</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This event is used as a replacement for the <emphasis>
MotionNotify</emphasis>
 event when possible. The fields are used as deltas to the most recent
<emphasis>
MotionNotify</emphasis>
 event encoded as a <emphasis>
MotionNotify</emphasis>
 event, <emphasis>
LbxQuickMotionDeltaEvent</emphasis>
, or <emphasis>
LbxMotionDeltaEvent</emphasis>
. Not every <emphasis>
MotionNotify</emphasis>
 event can be encoded as <emphasis>
a LbxMotionDeltaEvent</emphasis>
.
</para>


<para>
The encoding for this event is on <ulink url="lbx.htm#35310">See
LbxMotionDeltaEvent</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxReleaseCmapEvent</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
colormap</emphasis>
: Colormap</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This event notifies the proxy that it must release the grab on this colormap
via the ReleaseCmap request. <ulink url="lbx.htm#34675">See
LbxReleaseCmap</ulink>
</para>


<para>
The encoding for this event is on <ulink url="lbx.htm#14052">See
LbxReleaseCmapEvent</ulink>.
</para>


<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxFreeCellsEvent</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
colormap</emphasis>
: Colormap</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
pixelStart, pixelEnd</emphasis>
: CARD32</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
The <emphasis>
LbxFreeCells</emphasis>
 event is sent to a proxy that has a colormap grabbed to notify the proxy that
the reference count of the described cells were decremented to zero by the
server or another proxy. The reference count includes those by this proxy. The
proxy must update its copy of the colormap state accordingly if the colormap is
still grabbed, or if the proxy may in the future grab the colormap using
smart-grab mode. <ulink url="lbx.htm#10922">See LbxGrabCmap</ulink>
</para>


<para>
The pixelStart and pixelEnd fields of the event denote a continuous range of
cells that were freed.
</para>


<para>
The encoding for this event is on <ulink url="lbx.htm#14731">See
LbxFreeCellsEvent</ulink>.
</para>

</sect2>
<sect2 id='responses'>
<title>Responses</title>

<para>
Responses are messages from the server to the proxy that not, strictly
speaking, events, replies or errors.
</para>

<informaltable frame='none' tabstyle='proto'>
  <?dbfo keep-together="always" ?>
  <tgroup cols='1' align='left' colsep='0' rowsep='0'>
  <colspec colname='c1' colwidth="1.0*"/>
  <thead>
    <row>
      <entry role='protoname'>LbxDeltaResponse</entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry role='protoargs'><emphasis>
count</emphasis>
: CARD8</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
cache-index</emphasis>
: CARD8</entry>
    </row>
    <row>
      <entry role='protoargs'><emphasis>
diffs</emphasis>
: LISTofDIFFITEM</entry>
    </row>
  </tbody>
  </tgroup>
</informaltable>

<para>
This response carries an event, reply, or error that has been encoded relative
to a message in the response delta cache. The <emphasis>
cache-index</emphasis>
 field is the index into the cache. Each entry in <emphasis>
diffs</emphasis>
 provides a byte offset and replacement value to use in reconstructing the
response.
</para>


<para>
The encoding for this event is on <ulink url="lbx.htm#17100">See
LbxDeltaResponse</ulink>.
</para>


</sect2>
</sect1>
<sect1 id='algorithm_naming'>
<title>Algorithm Naming</title>

<para>
To avoid potential clashes between different but similar algorithms for stream,
bitmap, and pixmap compression, the following naming scheme will be adhered to:
</para>


<para>
Each algorithm has a unique name, which is a STRING8, of the following form:
</para>


<para>
   &lt;organization&gt;-&lt;some-descriptive-name&gt;
</para>


<para>
The organization field above is the organization name as registered in section
1 of the X Registry (the registry is provided as a free service by the X
Consortium.) This prevents conflicts among different vendor’s extensions.
</para>


<para>
As an example, the X Consortium defines a zlib-based stream compression
algorithm called XC-ZLIB.
</para>


</sect1>
<sect1 id='encoding'>
<title>Encoding</title>

<para>
The syntax and types used in the encoding are taken from the X protocol
encoding. Where LBX defines new types, they are defined earlier in this
document.
</para>


<para>
As in the X protocol, in various cases, the number of bytes occupied by a
component will be specified by a lowercase single-letter variable name instead
of a specific numeric value, and often some other component will have its value
specified as a simple numeric expression involving these variables. Components
specified with such expressions are always interpreted as unsigned integers.
The scope of such variables is always just the enclosing request, reply, error,
event, or compound type structure.
</para>


<para>
For unused bytes, the encode-form is:
</para>

<literallayout>
N            unused
</literallayout>

<para>
If the number of unused bytes is variable, the encode-form typically is:
</para>

<literallayout>
p            unused, p=pad(E)
</literallayout>

<para>
where E is some expression, and pad(E) is the number of bytes needed to round E
up to a multiple of four.
</para>


<para>
pad(E) = (4 - (E mod 4)) mod 4
</para>


<para>
In many of the encodings, the length depends on many variable length fields.
The variable L is used to indicate the number of padded 4 byte units needed to
carry the request. Similarly, the variable Lpad indicates the number of bytes
needed to pad the request to a 4 byte boundary.
</para>

<literallayout>
For counted lists there is a common encoding of NLISTofFOO:
</literallayout>

<literallayout class='monospaced'>
<emphasis role='bold'>NLISTofFOO</emphasis>
1      m      num items
m      LISTofFOO      items
</literallayout>

<para>
For cached GC and Drawables:
</para>

<literallayout>
<emphasis role='bold'>LBXGCANDDRAWUPDATE</emphasis>
4 or 0      DRAWBLE      optional drawable
4 or 0      GC           optional GC
</literallayout>



<literallayout>
<emphasis role='bold'>LBXGCANDDRAWABLE</emphasis>
8      LBXGCANDDRAWENT      cache-entries
8                           unused
m      LBXGCANDDRAWUPDATE   optional GC and Drawable
</literallayout>


<sect2 id='errors2'>
<title>Errors</title>

<literallayout class='monospaced'>
<emphasis role='bold'>LbxClient</emphasis>
1      0          Error
1      CARD8      error-base + 0
2      CARD16     sequence number
4                 unused
2      CARD16     lbx opcode
1      CARD8      major opcode
21                unused
</literallayout>

</sect2>
<sect2 id='requests2'>
<title>Requests</title>

<literallayout class='monospaced'>
<emphasis role='bold'>LbxQueryVersion</emphasis>
1      CARD8      opcode
1      0          lbx opcode
2      1          request length
=&gt;
1      1          Reply
1                 unused
2      CARD16     sequence number
4      0          reply length
2      CARD16     major version
2      CARD16     minor version
20                unused
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#18761">See
LbxQueryVersion</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxStartProxy</emphasis>
1      CARD8                      opcode
1      1                          lbx opcode
2      L                          request length
n      NLISTofOPTION-REQUEST      options
p                                 unused, p=pad(n)

<emphasis role='bold'>OPTION-REQUEST</emphasis>
1      OPTCODE                    option-code
m      OPTLEN                     option-request-byte-length, (b=m+a+1)
a      DELTAOPT or                option
       NLISTofNAMEDOPT or
       NLISTofSTR or
       NLISTofPIXMAPMETHOD or
       BOOL
</literallayout>

<para>
The encoding of the option field depends on the option-code.
See <ulink url="lbx.htm#35444">See StartProxy Options</ulink>.
</para>

<literallayout class='monospaced'>
1      OPTCODE                               option-code
0      LbxOptionDeltaProxy
1      LbxOptionDeltaServer
2      LbxOptionStreamCompression
3      LbxOptionBitmapCompression
4      LbxOptionPixmapCompression
5      LbxOptionMessageCompression              /* also known as squishing */
6      LbxOptionUseTags
7      LbxOptionColormapAllocation
255    LbxOptionExtension
</literallayout>

<para>
OPTLEN has two possible encodings, depending on the size of the value carried:
</para>

<literallayout class='monospaced'>
<emphasis role='bold'>OPTLEN</emphasis>
1      CARD8              b (0 &lt; b &lt;= 255)

<emphasis role='bold'>OPTLEN</emphasis>
1      0                  long length header
1      c                  length0, c = b &gt;&gt; 8
1      d                  length1, d= b &amp; #xff

<emphasis role='bold'>DELTAOPT</emphasis>
1      CARD8      min-cache-size
1      CARD8      max-cache-size
1      CARD8      preferred-cache-size
1      CARD8      min-message-length
1      CARD8      max-message-length (in 4-byte units)
1      CARD8      preferred-message-length

<emphasis role='bold'>NAMEDOPT</emphasis>
f      STR             type-name
1      g+1             option-data-length
g      LISTofBYTE      option-data (option specific)

<emphasis role='bold'>PIXMAPMETHOD</emphasis>
h      STR              name
1      BITMASK          format mask
1      j                depth count
j      LISTofCARD8      depths

=&gt;
=&gt;

1      1                 Reply
1      CARD8             count

0xff      options in request cannot be decoded
2      CARD16            sequence number
4      (a+p-32)/4        reply length
a      LISTofCHOICE      options-reply
p            unused, if (n&lt;24) p=24-n else p=pad(n)

<emphasis role='bold'>CHOICE</emphasis>
1      CARD8                request-option-index
b      OPTLEN               reply-option-byte-length
c      DELTACHOICE or       choice
      INDEXEDCHOICE or
      NLISTofINDEXEDOPT or
      NLISTofPIXMAPCHOICE or
      BOOL or
      INDEXEDCHOICE
</literallayout>

<para>
The encoding of the choice field depends on the option-code. See <ulink
url="lbx.htm#35444">See StartProxy Options</ulink>.
</para>

<literallayout class='monospaced'>
<emphasis role='bold'>DELTACHOICE</emphasis>
1      CARD8      preferred cache size
1      CARD8      preferred message length in 4-byte units

<emphasis role='bold'>INDEXEDCHOICE</emphasis>
1      CARD8           index
d      LISTofBYTE      data

<emphasis role='bold'>PIXMAPCHOICE</emphasis>
1      CARD8           index
1      CARD8           opcode
1      BITMASK         format mask
e      NLISTofCARD8    depths
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#20870">See
LbxStartProxy</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxStopProxy</emphasis>
1      CARD8      opcode
1      2          lbx opcode
2      1          request length
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#27455">See
LbxStopProxy</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxSwitch</emphasis>
1      CARD8      opcode
1      3          lbx opcode
2      2          request length
4      CARD32     client
</literallayout>

<para>
The description of this request is on
<ulink url="lbx.htm#33500">See LbxSwitch</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxNewClient</emphasis>
1      CARD8      opcode
1      4          lbx opcode
2      L          request length
4      CARD32     client
The remaining bytes of the request are the core connection setup.
=&gt;
If the connection is rejected, a core connection reply is sent. Otherwise the
reply has the form:
1      BOOL      success
1                change type
      0          no-deltas
      1          normal-client-deltas
      2          app-group-deltas
2      CARD16    major version
2      CARD16    minor version
2      1 + a     length
4      CARD32    tag id
</literallayout>

<para>
The remaining bytes depend on the value of change-type and length.
</para>

<para>
For no-deltas, the remaining bytes are the &quot;additional data&quot;
bytes of the core reply. (a = length of core reply, in 4 byte quantities).
</para>

<para>
For normal-client-deltas, the additional bytes have the form, with a length (a
= 1 +b):
</para>

<literallayout class='monospaced'>
4      CARD32                 resource id base
4b      LISTofSETofEVENT      root input masks
</literallayout>

<para>
For app-group-deltas, the additional bytes have the following form, with a
length of (a = 1 + 4c):
</para>

<literallayout class='monospaced'>
4      CARD32                resource id base
4      WINDOW                root id base
4      VISUALID              visual
4      COLORMAP              colormap
4      CARD32                white pixel
4      CARD32                black pixel
4c     LISTofSETofEVENT      root input masks
</literallayout>

<para>
The description of this request is on
<ulink url="lbx.htm#17810">See LbxNewClient</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxCloseClient</emphasis>
1      CARD8      opcode
1      5          lbx opcode
2      2          request length
4      CARD32     client
</literallayout>

<para>
The description of this request is on
<ulink url="lbx.htm#21625">See LbxCloseClient</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxModifySequence</emphasis>
1      CARD8      opcode
1      6          lbx opcode
2      2          request length
4      CARD32     offset to sequence number
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#36693">See
LbxModifySequence</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxAllowMotion</emphasis>
1      CARD8      opcode
1      7          lbx opcode
2      2          request length
4      CARD32     number of MotionNotify events
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#15895">See
LbxAllowMotion</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxIncrementPixel</emphasis>
1      CARD8      opcode
1      8          lbx opcode
2      3          request length
4      COLORMAP   colormap
4      CARD32      pixel
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#27227">See
LbxIncrementPixel</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxDelta</emphasis>
1      CARD8              opcode
1      9                  lbx opcode
2      1+(2n +p+2)/4      request length
1      n                  count of diffs
1      CARD8              cache index
2n      LISTofDIFFITEM    offsets and differences
p                         unused, p=pad(2n + 2)
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#26857">See
LbxDelta</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxGetModifierMapping</emphasis>
1      CARD8      opcode
1      10         lbx opcode
2      1          request length
=&gt;
1      1          Reply
1      n          keycodes-per-modifier
2      CARD16     sequence number
4      2n         reply length
4      CARD32     tag
20                unused
8n     LISTofKEYCODE      keycodes
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#37687">See
LbxGetModifierMapping</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxInvalidateTag</emphasis>
1      CARD8      opcode
1      12         lbx opcode
2      2          request length
4      CARD32     tag
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#12515">See
LbxInvalidateTag</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxPolyPoint</emphasis>
1      CARD8      opcode
1      13      lbx opcode
2      1+(m+n+p)/4      request length
m      LBXGCANDDRAWABLE      cache entries
n      LISTofLBXPOINT      points (n is data-dependent)
p      0      unused, p=Lpad
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#37179">See
LbxPolyPoint</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxPolyLine</emphasis>
1      CARD8      opcode
1      14      lbx opcode
2      1+(m+n+p)/4      request length
m      LBXGCANDDRAWABLE      cache entries
n      LISTofLBXPOINT      points (n is data-dependent)
p      0      unused, p=Lpad
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#16574">See
LbxPolyLine</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxPolySegment</emphasis>
1      CARD8      opcode
1      15      lbx opcode
2      1+(m+n+p)/4      request length
m      LBXGCANDDRAWABLE      cache entries
n      LISTofLBXSEGMENT      segments (n is data-dependent)
p      0      unused, p=Lpad
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#26077">See
LbxPolySegment</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxPolyRectangle</emphasis>
1      CARD8      opcode
1      16      lbx opcode
2      1+(m+n+p)/4      request length
m      LBXGCANDDRAWABLE      cache entries
n      LISTofLBXRECTANGLE      rectangles (n is data-dependent)
p      0      unused, p=pad(m+n)
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#40958">See
LbxPolyRectangle</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxPolyArc</emphasis>
1      CARD8      opcode
1      17      lbx opcode
2      1+(m+n+p)/4      request length
m      LBXGCANDDRAWABLE      cache entries
n      LISTofLBXARCS      arcs (n is data-dependent)
p      0      unused, p=Lpad
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#15317">See
LbxPolyArc</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxFillPoly</emphasis>
1      CARD8      opcode
1      18      lbx opcode
2      1+(3+m+n+p)/4      request length
1      LBXGCANDDRAWENT      cache entries
1            shape
0      Complex
1      Nonconvex
2      Convex
1      p      pad byte count
m      LBXGCANDDRAWUPDATE      optional gc and drawable
n      LISTofLBXPOINT      points (n is data-dependent)
p      0      unused, p=Lpad
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#35796">See
LbxFillPoly</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxPolyFillRectangle</emphasis>
1      CARD8      opcode
1      19      lbx opcode
2      1+(m+n+p)/4      request length
m      LBXGCANDDRAWABLE      cache entries
n      LISTofLBXRECTANGLE      rectangles (n is data-dependent)
p      0      unused, p=Lpad
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#25511">See
LbxPolyFillRectangle</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxPolyFillArc</emphasis>
1      CARD8      opcode
1      20      lbx opcode
2      1+(m+n+p)/4      request length
m      LBXGCANDDRAWABLE      cache entries
n      LISTofLBXARC      arcs (n is data-dependent)
p      0      unused, p=Lpad
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#42698">See
LbxPolyFillArc</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxGetKeyboardMapping</emphasis>
1      CARD8      opcode
1      21      lbx opcode
2      2      request length
1      KEYCODE      first keycode
1      m      count
2            unused
=&gt;
1      1      Reply
1      n      keysyms-per-keycode
2      CARD16      sequence number
4      nm      reply length (m = count field from the request)
4      CARD32      tag
20            unused
4nm      LISTofKEYSYM      keysyms
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#33719">See
LbxGetKeyboardMapping</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxQueryFont</emphasis>
1      CARD8      opcode
1      22      lbx opcode
2      2      request length
4      FONTABLE      font
=&gt;
1      1      Reply
1      BOOL      compression
2      CARD16      sequence number
4      L      reply length
4      CARD32      tag
20            unused
All of the following is conditional:
12      CHARINFO      min-bounds
4            unused
12      CHARINFO      max-bounds
4            unused
2      CARD16      min-char-or-byte2
2      CARD16      max-char-or-byte2
2      CARD16      default-char
2      n      number of FONTPROPs in properties
1            draw-direction
0      <emphasis>LeftToRight</emphasis>
1      <emphasis>RightToLeft</emphasis>
1      CARD8      min-byte1
1      CARD8      max-byte1
1      BOOL      all-chars-exist
2      INT16      font-ascent
2      INT16      font-descent
4      m      number of elements in char-infos
8n      LISTofFONTPROP      properties
and either
12m      LISTofCHARINFO      char-infos
or
m      LISTofLBXCHARINFO      char-infos
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#18818">See
LbxQueryFont</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxChangeProperty</emphasis>
1      CARD8      opcode
1      23      lbx opcode
2      6      request length
4      WINDOW      window
4      ATOM      property
4      ATOM      type
1      CARD8      format
1            mode
0      Replace
1      Preprend
2      Append
2            unused
4      CARD32      length of data in format units
            (= n for format = 8)
            (= n/2 for format = 16)
            (= n/4 for format = 32)
=&gt;
1      1      Reply
1            unused
2      CARD16      sequence number
4      0      reply length
4      CARD32      tag
20            unused
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#40098">See
LbxChangeProperty</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxGetProperty</emphasis>
1      CARD8      opcode
1      24      lbx opcode
2      7      request length
4      WINDOW      window
4      ATOM      property
4      ATOM      type
0      AnyPropertyType
1      CARD8      delete
3            unused
4      CARD32      long-offset
4      CARD32      long-length
=&gt;
1      1      Reply
1      CARD8      format
2      CARD16      sequence number
4      CARD32      reply length
4      ATOM      type
0      None
4      CARD32      bytes-after
4      CARD32      length of value in format units
            (= 0 for format = 0)
            (= n for format = 8)
            (= n/2 for format = 16)
            (= n/4 for format = 32)
4      CARD32      tag
8            unused
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#31397">See
LbxGetProperty</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxTagData</emphasis>
1      CARD8      opcode
1      25      lbx opcode
2      3+(n+p)/4      request length
4      CARD32      tag
4      CARD32      length of data in bytes
n      LISTofBYTE      data
p            unused, p=pad(n)
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#17987">See
LbxTagData</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxCopyArea</emphasis>
1      CARD8      opcode
1      26      lbx opcode
2      L      request length
1      CARD8      source drawable cache entry
1      LBXGCANDDRAWENT      cache entries
4 or 0      DRAWABLE      optional source drawable
b      LBXGCANDDRAWUPDATE      optional gc and dest drawable
c      LBXPINT16      src-x
d      LBXPINT16      src-y
e      LBXPINT16      dst-x
f      LBXPINT16      dst-y
g      LBXCARD16      width
h      LBXCARD16      height
p            unused, p=Lpad
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#11409">See
LbxCopyArea</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxCopyPlane</emphasis>
1      CARD8      opcode
1      27      lbx opcode
2      L      request length
4      CARD32      bit plane
1      CARD8      source drawable cache entry
1      LBXGCANDDRAWENT      cache entries
4 or 0      DRAWABLE      optional source drawable
b      LBXGCANDDRAWUPDATE      optional gc and dest drawable
c      LBXPINT16      src-x
d      LBXPINT16      src-y
e      LBXPINT16      dst-x
f      LBXPINT16      dst-y
g      LBXCARD16      width
h      LBXCARD16      height
p            unused, p=Lpad
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#36772">See
LbxCopyPlane</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxPolyText8</emphasis>
1      CARD8      opcode
1      28      lbx opcode
2      L      request length
1      LBXGCANDDRAWENT      cache entries
a      LBXGCANDDRAWUPDATE      optional gc and drawable
b      LBXPINT16      x
c      LBXPINT16      y
n      LISTofTEXTITEM8      items
p            unused, p=Lpad
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#23201">See
LbxPolyText8</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxPolyText16</emphasis>
1      CARD8      opcode
1      29      lbx opcode
2      L      request length
1      LBXGCANDDRAWENT      cache entries
a      LBXGCANDDRAWUPDATE      optional gc and drawable
b      LBXPINT16      x
c      LBXPINT16      y
2n      LISTofTEXTITEM16      items
p            unused, p=Lpad
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#13228">See
LbxPolyText16</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxImageText8</emphasis>
1      CARD8      opcode
1      30      lbx opcode
2      L      request length
1      LBXGCANDDRAWENT      cache entries
a      LBXGCANDDRAWUPDATE      optional gc and drawable
b      LBXPINT16      x
c      LBXPINT16      y
n      STRING8      string
p            unused, p=Lpad
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#10990">See
LbxImageText8</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxImageText16</emphasis>
1      CARD8      opcode
1      31      lbx opcode
2      L      request length
1      LBXGCANDDRAWENT      cache entries
a      LBXGCANDDRAWUPDATE      optional gc and drawable
b      LBXPINT16      x
c      LBXPINT16      y
2n      STRING16      string
p            unused, p=Lpad
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#39584">See
LbxImageText16</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxQueryExtension</emphasis>
1      CARD8      opcode
1      32      lbx opcode
2      2+(n+p)/4      request length
4      n      length of extension name
n      STRING8      extension name
p            unused, p=pad(n)
=&gt;
1      1      Reply
1      n      number of requests in the extension
2      CARD16      sequence number
4      0 or 2*(m + p)      reply length, m = (n+7)/8
1      BOOL      present
1      CARD8      major opcode
1      CARD8      first event
1      CARD8      first error
20            unused
m      LISTofMASK      optional reply-mask
p            unused, p=pad(m)
m      LISTofMASK      optional event-mask
p            unused, p=pad(m)
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#36662">See
LbxQueryExtension</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxPutImage</emphasis>
1      CARD8      opcode
1      33      lbx opcode
2      L      request length
1      CARD8      compression method
1      LBXGCANDDRAWENT      cache entries
a      PIPACKED            bit-packed
b      LBXGCANDDRAWUPDATE      optional gc and drawable
c      LBXCARD16      width
d      LBXCARD16      height
e      LBXPINT16      x
f      LBXPINT16      y
n      LISTofBYTE      compressed image data
p            unused, p=Lpad
</literallayout>

<para>
If there is no left padding and the depth is less than or equal to nine,
PIPPACKED is encoded as follows:
</para>

<literallayout class='monospaced'>
<emphasis role='bold'>PIPACKED</emphasis>
1      #x80 | (format &lt;&lt; 5) | ((depth -1) &lt;&lt; 2)
</literallayout>

<para>
Otherwise PIPACKED is defined as:
</para>

<literallayout class='monospaced'>
<emphasis role='bold'>PIPACKED</emphasis>
1      (depth -1) &lt;&lt; 2)
1      (format &lt;&lt; 5) | left-pad
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#21218">See
LbxPutImage</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxGetImage</emphasis>
1      CARD8      opcode
1      34      lbx opcode
2      6      request length
4      DRAWABLE      drawable
2      INT16      x
2      INT16      y
2      CARD16      width
2      CARD16      height
4      CARD32      plane mask
1      CARD8      format
3            unused
=&gt;
1      1      Reply
1      CARD8      depth
2      CARD16      sequence number
4      (n+p)/4      reply length
4      (m+p)/4      X reply length; if uncompressed, m=n
4      VISUALID      visual
0      None
1            compression method
15            unused
n      LISTofBYTE      data
p            unused, p=pad(n)
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#26896">See
LbxGetImage</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxBeginLargeRequest</emphasis>
1      CARD8      opcode
1      35      lbx opcode
2      2      request length
4      CARD32      large request length
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#31209">See
LbxBeginLargeRequest</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxLargeRequestData</emphasis>
1      CARD8      opcode
1      36      lbx opcode
2      1+n      request length
4n      LISTofBYTE      data
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#36982">See
LbxLargeRequestData</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxEndLargeRequest</emphasis>
1      CARD8      opcode
1      37      lbx opcode
2      1      request length
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#31841">See
LbxEndLargeRequest</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxInternAtoms</emphasis>
1      CARD8      opcode
1      38      lbx opcode
2      1+(2+m+n+p)/4      request length
2      m      num-atoms
n      LISTofLONGSTR      names
p            pad p=Lpad
=&gt;
1      1      Reply
1            unused
2      CARD16      sequence number
4      a      reply length, a = MAX(m - 6, 0)
4*m      LISTofATOM      atoms
p            pad p = MAX(0, 4*(6 - m))
&nbsp;
LONGSTR
2      c      string length
c      STRING8      string
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#21636">See
LbxInternAtoms</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxGetWinAttrAndGeom</emphasis>
1      CARD8      opcode
1      39      lbx opcode
2      2      request length
4      CARD32      window id
=&gt;
1      1      Reply
1            backing store
0      NotUseful
1      WhenMapped
2      Always
2      CARD16      sequence number
4      7      reply length
4      VISUALID      visual id
2            class
1      InputOutput
2      InputOnly
1      BITGRAVITY      bit gravity
1      WINGRAVITY      window gravity
4      CARD32      backing bit planes
4      CARD32      backing pixel
1      BOOL      save under
1      BOOL      map installed
1            map state
0      Unmapped
1      Unviewable
2      Viewable
1      BOOL      override
4      COLORMAP      colormap
4      SETofEVENT      all events mask
4      SETofEVENT      your event mask
2      SETofDEVICEEVENT      do not propagate mask
2            unused
4      WINDOW      root
2      INT16      x
2      INT16      y
2      CARD16      width
2      CARD16      height
2      CARD16      border width
1      CARD8      depth
1            unused
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#39382">See
LbxGetWinAttrAndGeom</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxGrabCmap</emphasis>
1      CARD8      opcode
1      40      lbx opcode
2      2      request length
4      COLORMAP      colormap
=&gt;
</literallayout>

<para>
If smart-grab is true, the reply is as follows:
</para>

<literallayout class='monospaced'>
1      1      Reply
1      #x80      flags
2      CARD16      sequence number
4      0      reply length
24            unused

If smart-grab is false, the reply is as follows:

1      1      Reply
1            flags (set of)
       #x40      auto-release
       #x20      three-channels
       #x10      two-byte-pixels
lower four bits specifies bits-per-pixel
2      CARD16      sequence number
4      L      reply length
m      CHAN or CHANNELS      cells (CHAN if !three-channels)
p      0      pad(m)

<emphasis role='bold'>CHANNELS</emphasis>
a      CHAN      red
1      5            next channel
b      CHAN      green
1      5      next channel
c      CHAN      blue
1      0      list end

<emphasis role='bold'>CHAN</emphasis>
d      LISTofLBXPIXEL

<emphasis role='bold'>LBXPIXEL</emphasis>
e      PIXELPRIVATE or
      PIXELPRIVATERANGE or
      PIXELALLOC or
      PIXELALLOCRANGE

<emphasis role='bold'>PIXELPRIVATE</emphasis>
1      1      pixel-private
f      PIXEL      pixel

<emphasis role='bold'>PIXEL</emphasis>
f      CARD8 or CARD16      (CARD8 if !two-byte-pixels)

<emphasis role='bold'>PIXELPRIVATERANGE</emphasis>
1      2      pixel-private-range
f      PIXEL      fist-pixel
f      PIXEL      last-pixel

<emphasis role='bold'>PIXELALLOC</emphasis>
1      3      pixel-private
f      PIXEL      pixel
g      COLORSINGLE or COLORTRIPLE      color       (COLORSINGLE if
three-channels)

<emphasis role='bold'>COLORSINGLE</emphasis>
h      CARD8 or CARD16      value (CARD8       if bits-per-rgb =&lt; 7)

<emphasis role='bold'>COLORTRIPLE</emphasis>
h      COLORSINGLE      red
h      COLORSINGLE      green
h      COLORSINGLE      blue

<emphasis role='bold'>PIXELALLOCRANGE</emphasis>
1      4      pixel-private
f      PIXEL      first-pixel
f      PIXEL      last-pixel
j      LISTofCOLORSINGLE or       color       (COLORSINGLE if three-channels)
      LISTofCOLORTRIPLE
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#10922">See
LbxGrabCmap</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxReleaseCmap</emphasis>
1      CARD8      opcode
1      41      lbx opcode
2      2      request length
4      COLORMAP      cmap
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#34675">See
LbxReleaseCmap</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxAllocColor</emphasis>
1      CARD8      opcode
1      42      lbx opcode
2      5      request length
4      COLORMAP      colormap
4      CARD32      pixel
2      CARD16      red
2      CARD16      green
2      CARD16            blue
2            unused
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#10446">See
LbxAllocColor</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxSync</emphasis>
1      CARD8      opcode
1      43      lbx opcode
2      1      request length
=&gt;
1      1      Reply
1      n      unused
2      CARD16      sequence number
4      0      reply length
24            unused
</literallayout>

<para>
The description of this request is on <ulink url="lbx.htm#30719">See
LbxSync</ulink>.
</para>



</sect2>
<sect2 id='events2'>
<title>Events</title>

<literallayout class='monospaced'>
<emphasis role='bold'>LbxSwitchEvent</emphasis>
1      base + 0      code
1      0      lbx type
2      CARD16      sequence number
4      CARD32      client
24            unused
</literallayout>

<para>
The description of this event is on <ulink url="lbx.htm#33748">See
LbxSwitchEvent</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxCloseEvent</emphasis>
1      base + 0      code
1      1      lbx type
2      CARD16      sequence number
4      CARD32      client
24            unused
</literallayout>

<para>
The description of this event is on <ulink url="lbx.htm#17292">See
LbxCloseEvent</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxInvalidateTagEvent</emphasis>
1      base + 0      code
1      3      lbx type
2      CARD16      sequence number
4      CARD32      tag
4            tag-type
1      <emphasis>LbxTagTypeModmap</emphasis>
2      <emphasis>LbxTagTypeKeymap</emphasis>
3      <emphasis>LbxTagTypeProperty</emphasis>
4      <emphasis>LbxTagTypeFont</emphasis>
5      <emphasis>LbxTagTypeConnInfo</emphasis>
20            unused
</literallayout>

<para>
The description of this event is on <ulink url="lbx.htm#23016">See
LbxInvalidateTagEvent</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxSendTagDataEvent</emphasis>
1      base + 0      code
1      4      lbx type
2      CARD16      sequence number
4      CARD32      tag
4            tag-type
3      <emphasis>LbxTagTypeProperty</emphasis>
20            unused
</literallayout>

<para>
The description of this event is on <ulink url="lbx.htm#20373">See
LbxSendTagDataEvent</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxListenToOne</emphasis>
1      base + 0      code
1      5      lbx type
2      CARD16      sequence number
4      CARD32      client
<emphasis>#xFFFFFFFF</emphasis>
a client not managed by the proxy
24            unused
</literallayout>

<para>
The description of this event is on <ulink url="lbx.htm#25209">See
LbxListenToOne</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxListenToAll</emphasis>
1      base + 0      code
1      6      lbx type
2      CARD16      sequence number
28            unused
</literallayout>

<para>
The description of this event is on <ulink url="lbx.htm#11095">See
LbxListenToAll</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxQuickMotionDeltaEvent</emphasis>
1      base + 1      code
1      CARD8      delta-time
1      INT8      delta-x
1      INT8      delta-y
</literallayout>

<para>
This event is not padded to 32 bytes.
</para>


<para>
The description of this event is on <ulink url="lbx.htm#40268">See
LbxQuickMotionDeltaEvent</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxMotionDeltaEvent</emphasis>
1      base + 0      code
1      7                  lbx type
1      INT8      delta-x
1      INT8      delta-y
2      CARD16      delta-time
2      CARD16      delta-sequence
</literallayout>

<para>
This event is not padded to 32 bytes.
</para>


<para>
The description of this event is on <ulink url="lbx.htm#30033">See
LbxMotionDeltaEvent</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxReleaseCmapEvent</emphasis>
1      base + 0      code
1      8                  lbx type
2      CARD16      sequence number
4      COLORMAP      colormap
24            unused
</literallayout>

<para>
The description of this event is on <ulink url="lbx.htm#19129">See
LbxReleaseCmapEvent</ulink>.
</para>


<literallayout class='monospaced'>
<emphasis role='bold'>LbxFreeCellsEvent</emphasis>
1      base + 0      code
1      9                  lbx type
2      CARD16      sequence number
4      COLORMAP      colormap
4      PIXEL      pixel start
4      PIXEL      pixel end
16            unused
</literallayout>

<para>
The description of this event is on <ulink url="lbx.htm#38041">See
LbxFreeCellsEvent</ulink>.
</para>


</sect2>
<sect2 id='re_encoding_of_x_events'>
<title>Re-encoding of X Events</title>

<para>
The X protocol requires all X events to be 32 bytes. The LBX server reduces the
number of bytes sent between the server and the proxy for some X events by not
appending unused pad bytes to the event data. The offsets of X event data are
unchanged. The proxy will pad the events to 32 bytes before passing them on to
the client.
</para>


<para>
LBX reencodes X event representations into the following sizes, if squishing is
enabled:
</para>

<para><programlisting>
KeyOrButton            32
EnterOrLeave           32
Keymap                 32
Expose                 20
GraphicsExposure       24
NoExposure             12
VisibilityNotify       12
CreateNotify           24
DestroyNotify          12
UnmapNotify            16
MapNotify              16
MapRequest             12
Reparent               24
ConfigureNotify        28
ConfigureRequest       28
GravityNotify          16
ResizeRequest          12
Circulate              20
Property      Notify   20
SelectionClear         20
SelectionRequest       28
SelectionNotify        24
Colormap      Notify   16
MappingNotify          8
ClientMessage          32
Unknown                32
</programlisting></para>

</sect2>
<sect2 id='responses2'>
<title>Responses</title>

<literallayout class='monospaced'>
<emphasis role='bold'>LbxDeltaResponse</emphasis>
1      event_base + 0      event code
1      2      lbx type
2      1+(2+2n+p)/4      request length
1      n      count of diffs
1      CARD8      cache index
2n      LISTofDIFFITEM      offsets and differences
p            unused, p=pad(2n)
</literallayout>

<para>
The description of this response is on <ulink url="lbx.htm#34042">See
LbxDeltaResponse</ulink>.
</para>

</sect2>
</sect1>
</article>