diff options
Diffstat (limited to 'app/xterm/graphics_sixel.c')
| -rw-r--r-- | app/xterm/graphics_sixel.c | 52 |
1 files changed, 35 insertions, 17 deletions
diff --git a/app/xterm/graphics_sixel.c b/app/xterm/graphics_sixel.c index 410199eec..876642289 100644 --- a/app/xterm/graphics_sixel.c +++ b/app/xterm/graphics_sixel.c @@ -1,4 +1,4 @@ -/* $XTermId: graphics_sixel.c,v 1.36 2022/02/21 23:13:48 tom Exp $ */ +/* $XTermId: graphics_sixel.c,v 1.38 2022/10/10 15:09:41 tom Exp $ */ /* * Copyright 2014-2021,2022 by Ross Combs @@ -109,15 +109,24 @@ typedef struct { int col; /* context used during parsing */ } SixelContext; -/* sixel scrolling: - * VK100/GIGI ? (did it even support Sixel?) - * VT125 unsupported - * VT240 unsupported - * VT241 unsupported - * VT330 mode setting - * VT382 ? - * VT340 mode setting - * dxterm ? +/* SIXEL SCROLLING, which is on by default in VT3xx terminals, can be + * turned off to better emulate VT2xx terminals by setting Sixel + * Display Mode (DECSDM) + * + * SIXEL DISPLAY MODE SIXEL SCROLLING + * VT125 Always on Unsupported + * VT240 Always on Unsupported + * VT241 Always on Unsupported + * VT330 Available via DECSDM Default mode + * VT382 Available via DECSDM Default mode + * VT340 Available via DECSDM Default mode + * VK100/GIGI No sixel support No sixel support + * + * dxterm (DECterm) emulated a VT100 series terminal, and supported sixels + * according to 1995 posting to comp.os.vms: + * https://groups.google.com/g/comp.os.vms/c/XAUMmLtC8Yk + * though not DRCS according to + * http://odl.sysworks.biz/disk$axpdocdec023/office/dwmot126/vmsdw126/relnotes/6470pro_004.html */ static void @@ -250,17 +259,26 @@ finished_parsing(XtermWidget xw, Graphic *graphic) + FontWidth(screen) - 1) / FontWidth(screen))); } else { - /* FIXME: At least of the VT382 the vertical position appears to be - * truncated (rounded toward zero after converting to character row. - * This code rounds up, which seems more useful, but it would be - * better to be compatible. Verify this is true on a VT3[34]0 as - * well. + /* NOTE: XTerm follows the VT382 behavior in text cursor + * placement. The VT382's vertical position appears to be + * truncated (rounded toward zero) after converting to character + * row. While rounding up is more often what is desired, so as to + * not overwrite the image, doing so automatically would cause text + * or graphics to scroll off the top of the screen. Therefore, + * applications must add their own newline character, if desired, + * after a sixel image. + * + * FIXME: The VT340 also rounds down, but it seems to have a + * strange behavior where, on rare occasions, two newlines are + * required to advance beyond the end of the image. This appears + * to be a firmware bug, but it should be added as an option for + * compatibility. */ - new_row = (graphic->charrow + new_row = (graphic->charrow - 1 + (((graphic->actual_height * graphic->pixh) + FontHeight(screen) - 1) / FontHeight(screen))); - new_col = 0; + new_col = graphic->charcol; } TRACE(("setting text position after %dx%d\t%.1f start (%d %d): cursor (%d,%d)\n", |