Initial xbacklight program

1 files changed, 214 insertions, 0 deletions

diff --git a/xbacklight.c b/xbacklight.c
new file mode 100644
index 0000000..df99905
--- /dev/null
+++ b/xbacklight.c
@@ -0,0 +1,214 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <X11/Xatom.h>
+#include <X11/Xlib.h>
+#include <X11/extensions/Xrandr.h>
+
+typedef enum { Get, Set, Inc, Dec } op_t;
+
+static char *program_name;
+
+static Atom backlight;
+
+static void
+usage (void)
+{
+    fprintf(stderr, "usage: %s [options]\n", program_name);
+    fprintf(stderr, "  where options are:\n");
+    fprintf(stderr, "  -display <display> or -d <display>\n");
+    fprintf(stderr, "  -help\n");
+    fprintf(stderr, "  -set <percentage> or = <percentage>\n");
+    fprintf(stderr, "  -inc <percentage> or + <percentage>\n");
+    fprintf(stderr, "  -dec <percentage> or - <percentage>\n");
+    fprintf(stderr, "  -get\n");
+    /*NOTREACHED*/
+    exit (1);
+}
+
+static long
+backlight_get (Display *dpy, RROutput output)
+{
+    unsigned long   nitems;
+    unsigned long   bytes_after;
+    unsigned char   *prop;
+    Atom	    actual_type;
+    int		    actual_format;
+    long	    value;
+    
+    if (XRRGetOutputProperty (dpy, output, backlight,
+			      0, 4, False, False, None,
+			      &actual_type, &actual_format,
+			      &nitems, &bytes_after, &prop) != Success)
+	return -1;
+    if (actual_type != XA_INTEGER || nitems != 1 || actual_format != 32)
+	value = -1;
+    else
+	value = *((long *) prop);
+    XFree (prop);
+    return value;
+}
+
+static void
+backlight_set (Display *dpy, RROutput output, long value)
+{
+    XRRChangeOutputProperty (dpy, output, backlight, XA_INTEGER, 32,
+			     PropModeReplace, (unsigned char *) &value, 1);
+}
+
+int
+main (int argc, char **argv)
+{
+    char    *dpy_name = NULL;
+    Display *dpy;
+    int	    screen;
+    int	    major, minor;
+    op_t    op = Get;
+    int	    value = 0;
+    int	    i;
+
+    program_name = argv[0];
+
+    for (i = 1; i < argc; i++)
+    {
+	if (!strcmp (argv[i], "-display") || !strcmp ("-d", argv[i]))
+	{
+	    if (++i >= argc) usage();
+	    dpy_name = argv[i];
+	    continue;
+	}
+	if (!strcmp (argv[i], "-set") || !strcmp (argv[i], "="))
+	{
+	    if (++i >= argc) usage();
+	    op = Set;
+	    value = atoi (argv[i]);
+	    continue;
+	}
+	if (argv[i][0] == '=' && isdigit (argv[i][1]))
+	{
+	    op = Set;
+	    value = atoi (argv[i] + 1);
+	    continue;
+	}
+	if (!strcmp (argv[i], "-inc") || !strcmp (argv[i], "+"))
+	{
+	    if (++i >= argc) usage();
+	    op = Inc;
+	    value = atoi (argv[i]);
+	    continue;
+	}
+	if (argv[i][0] == '+' && isdigit (argv[i][1]))
+	{
+	    op = Inc;
+	    value = atoi (argv[i] + 1);
+	    continue;
+	}
+	if (!strcmp (argv[i], "-dec") || !strcmp (argv[i], "-"))
+	{
+	    if (++i >= argc) usage();
+	    op = Dec;
+	    value = atoi (argv[i]);
+	    continue;
+	}
+	if (argv[i][0] == '-' && isdigit (argv[i][1]))
+	{
+	    op = Dec;
+	    value = atoi (argv[i] + 1);
+	    continue;
+	}
+	if (!strcmp (argv[i], "-get") || !strcmp (argv[i], "-g"))
+	{
+	    op = Get;
+	    continue;
+	}
+	if (!strcmp (argv[i], "-help") || !strcmp (argv[i], "-?"))
+	{
+	    usage ();
+	}
+    }
+    dpy = XOpenDisplay (dpy_name);
+    if (!dpy)
+    {
+	fprintf (stderr, "Cannot open display \"%s\"\n",
+		 XDisplayName (dpy_name));
+	exit (1);
+    }
+    if (!XRRQueryVersion (dpy, &major, &minor))
+    {
+	fprintf (stderr, "RandR extension missing\n");
+	exit (1);
+    }
+    if (major < 1 || (major == 1 && minor < 2))
+    {
+	fprintf (stderr, "RandR version %d.%d too old\n", major, minor);
+	exit (1);
+    }
+    backlight = XInternAtom (dpy, "BACKLIGHT", True);
+    if (backlight == None)
+    {
+	fprintf (stderr, "No outputs have backlight property\n");
+	exit (1);
+    }
+    for (screen = 0; screen < ScreenCount (dpy); screen++)
+    {
+	Window		    root = RootWindow (dpy, screen);
+	XRRScreenResources  *resources = XRRGetScreenResources (dpy, root);
+	int		    o;
+	
+	if (!resources) continue;
+	for (o = 0; o < resources->noutput; o++)
+	{
+	    RROutput	output = resources->outputs[o];
+	    XRRPropertyInfo *info;
+	    double    	cur, new, step;
+	    double	min, max;
+	    double	set;
+
+	    cur = backlight_get (dpy, output);
+	    if (cur != -1)
+	    {
+		info = XRRQueryOutputProperty (dpy, output, backlight);
+		if (info)
+		{
+		    if (info->range && info->num_values == 2)
+		    {
+			min = info->values[0];
+			max = info->values[1];
+			if (op == Get) {
+			    printf ("%f\n", (cur - min) * 100 / (max - min));
+			} else {
+			    set = value * (max - min) / 100;
+			    switch (op) {
+			    case Set:
+				new = min + set;
+				break;
+			    case Inc:
+				new = cur + set;
+				break;
+			    case Dec:
+				new = cur - set;
+				break;
+			    }
+			    if (new > max) new = max;
+			    if (new < min) new = min;
+			    step = (new - cur) / 50;
+			    for (i = 0; i < 50; i++)
+			    {
+				if (i == 49)
+				    cur = new;
+				else
+				    cur += step;
+				backlight_set (dpy, output, (long) cur);
+				XFlush (dpy);
+				usleep (10 * 1000);
+			    }
+			}
+		    }
+		    XFree (info);
+		}
+	    }
+	}
+							   
+	XRRFreeScreenResources (resources);
+    }
+    XSync (dpy, False);
+}