[screen-devel] [PATCH 1/2] [screen-v4] ansi: add support for xterm OSC 11

[Lubomir Rintel]

It allows for getting and setting the background color. Notably, Vim uses
OSC 11 to learn whether it's running on a light or dark colored terminal
and choose a color scheme accordingly.

Tested with gnome-terminal and xterm. When called with "?" argument the
current background color is returned:

  $ echo -ne "\e]11;?\e\\"
  $ 11;rgb:2323/2727/2929

Signed-off-by: Lubomir Rintel <address@hidden>
(cherry picked from commit 7059bff20a28778f9d3acf81cad07b1388d02309)
---
 src/ansi.c    | 17 ++++++++++-------
 src/display.c |  3 ++-
 src/process.c |  2 +-
 3 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/src/ansi.c b/src/ansi.c
index d2b3cbc..28e3529 100644
--- a/src/ansi.c
+++ b/src/ansi.c
@@ -1562,25 +1562,28 @@ StringEnd()
        }
 #endif
 #ifdef RXVT_OSC
-      if (typ == 0 || typ == 1 || typ == 2 || typ == 20 || typ == 39 || typ == 
49)
+      if (typ == 0 || typ == 1 || typ == 2 || typ == 11 || typ == 20 || typ == 
39 || typ == 49)
        {
          int typ2;
          typ2 = typ / 10;
-         if (--typ2 < 0)
-           typ2 = 0;
          if (strcmp(curr->w_xtermosc[typ2], p))
            {
-             strncpy(curr->w_xtermosc[typ2], p, sizeof(curr->w_xtermosc[typ2]) 
- 1);
-             curr->w_xtermosc[typ2][sizeof(curr->w_xtermosc[typ2]) - 1] = 0;
+             if (typ != 11 || strcmp("?", p))
+               {
+                 strncpy(curr->w_xtermosc[typ2], p, 
sizeof(curr->w_xtermosc[typ2]) - 1);
+                 curr->w_xtermosc[typ2][sizeof(curr->w_xtermosc[typ2]) - 1] = 
0;
+               }
 
              for (display = displays; display; display = display->d_next)
                {
                  if (!D_CXT)
                    continue;
                  if (D_forecv->c_layer->l_bottom == &curr->w_layer)
-                   SetXtermOSC(typ2, curr->w_xtermosc[typ2]);
-                 if ((typ2 == 2 || typ2 == 3) && D_xtermosc[typ2])
+                   SetXtermOSC(typ2, p);
+                 if ((typ2 == 3 || typ2 == 4) && D_xtermosc[typ2])
                    Redisplay(0);
+                 if (typ == 11 && !strcmp("?", p))
+                   break;
                }
            }
        }
diff --git a/src/display.c b/src/display.c
index 190d418..dbc7d74 100644
--- a/src/display.c
+++ b/src/display.c
@@ -2939,6 +2939,7 @@ char *s;
 {
   static char *oscs[][2] = {
     { WT_FLAG ";", "screen" }, /* set window title */
+    { "11;", ""},       /* background RGB */
     { "20;", "" },      /* background */
     { "39;", "black" }, /* default foreground (black?) */
     { "49;", "white" }  /* default background (white?) */
@@ -2966,7 +2967,7 @@ void
 ClearAllXtermOSC()
 {
   int i;
-  for (i = 3; i >= 0; i--)
+  for (i = 4; i >= 0; i--)
     SetXtermOSC(i, 0);
   if (D_xtermosc[0])
     AddStr("\033[23;" WT_FLAG "t");    /* unstack titles (xterm patch #251) */
diff --git a/src/process.c b/src/process.c
index ec5a911..3c7cce8 100644
--- a/src/process.c
+++ b/src/process.c
@@ -7190,7 +7190,7 @@ RefreshXtermOSC()
   struct win *p;
 
   p = Layer2Window(D_forecv->c_layer);
-  for (i = 3; i >=0; i--)
+  for (i = 4; i >=0; i--)
     SetXtermOSC(i, p ? p->w_xtermosc[i] : 0);
 }
 #endif
-- 
2.17.1