osc: implement OSC 17+19: change selection background/foreground colors

And of course, we also implement the corresponding reset sequences,
OSC 117+119.

CHANGELOG.md

@@ -30,6 +30,8 @@
 
 * URxvt OSC-11 extension to set background alpha
   (https://codeberg.org/dnkl/foot/issues/436).
+* OSC 17+19 - change selection background/foreground color.
+* OSC 117+119 - reset selection background/foreground color.
 
 
 ### Changed

doc/foot-ctlseqs.7.scd

@@ -564,7 +564,7 @@ All _OSC_ sequences begin with *\\E]*, sometimes abbreviated _OSC_.
 |  \\E] 4 ; _c_ ; _spec_ \\E\\ 
 :  xterm
 :  Change color number _c_ to _spec_, where _spec_ is a color in
-   *XParseColor* format. foot only supports RGB colors; either
+   XParseColor format. foot only supports RGB colors; either
    *rgb:<red>/<green>/<blue>*, or the legacy format (*#rgb*).
 |  \\E] 7 ; _Uri_ \\E\\ 
 :  iTerm2
@@ -579,7 +579,7 @@ All _OSC_ sequences begin with *\\E]*, sometimes abbreviated _OSC_.
 |  \\E] 10 ; _spec_ \\E\\ 
 :  xterm
 :  Change the default foreground color to _spec_, a color in
-   *XParseColor* format.
+   XParseColor format.
 |  \\E] 11 ; _spec_ \\E\\ 
 :  xterm
 :  Change the default background color to _spec_, a color in
@@ -588,21 +588,30 @@ All _OSC_ sequences begin with *\\E]*, sometimes abbreviated _OSC_.
    75% alpha).
 |  \\E] 12 ; _spec_ \\E\\ 
 :  xterm
-:  Change cursor color to _spec_, a color in *XParseColor* format.
+:  Change cursor color to _spec_, a color in XParseColor format.
+|  \\E] 17 ; _spec_ \\E\\ 
+:  xterm
+:  Change selection background color to _spec_, a color in
+   XParseColor format.
+|  \\E] 19 ; _spec_ \\E\\ 
+:  xterm
+:  Change selection foreground color to _spec_, a color in XParseColor
+   format.
 |  \\E] 52 ; _Pc_ ; ? \\E\\ 
 :  xterm
 :  Send clipboard data. _Pc_ can be either *c*, *s* or *p*. *c* uses
    the clipboard as source, and *s* and *p* uses the primary
    selection. The response is *OSC 52 ; Pc ; <base64-encoded data>*,
-   where _Pc_ indicates the source used.
+   where _Pc_ denotes the source used.
 |  \\E] 52 ; _Pc_ ; _Pd_ \\E\\ 
 :  xterm
-:  Copy _Pd_ (base64 encoded text) to the clipboard. _Pc_ indicates the
+:  Copy _Pd_ (base64 encoded text) to the clipboard. _Pc_ denotes the
    target: *c* targets the clipboard and *s* and *p* the primary
    selection.
-|  \\E] 104 [; _c_] \\E\\ 
+|  \\E] 104 ; _c_ \\E\\ 
 :  xterm
-:  Reset color number _c_, or all colors (excluding the default
+:  Reset color number _c_ (multiple semicolon separated _c_ values may
+   be provided), or all colors (excluding the default
    foreground/background colors) if _c_ is omitted.
 |  \\E] 110 \\E\\ 
 :  xterm
@@ -613,6 +622,12 @@ All _OSC_ sequences begin with *\\E]*, sometimes abbreviated _OSC_.
 |  \\E] 112 \\E\\ 
 :  xterm
 :  Reset cursor color
+|  \\E] 117 \\E\\ 
+:  xterm
+:  Reset selection background color
+|  \\E] 119 \\E\\ 
+:  xterm
+:  Reset selection foreground color
 |  \\E] 555 \\E\\ 
 :  foot
 :  Flash the entire terminal (foot extension)

osc.c

@@ -679,8 +679,10 @@ osc_dispatch(struct terminal *term)
         break;
 
     case 10:
-    case 11: {
+    case 11:
-        /* Set default foreground/background color */
+    case 17:
+    case 19: {
+        /* Set default foreground/background/highlight-bg/highlight-fg color */
 
         /* Client queried for current value */
         if (strlen(string) == 1 && string[0] == '?') {
@@ -714,7 +716,11 @@ osc_dispatch(struct terminal *term)
         }
 
         LOG_DBG("change color definition for %s to %06x",
-                param == 10 ? "foreground" : "background", color);
+                param == 10 ? "foreground" :
+                param == 11 ? "background" :
+                param == 17 ? "selection background" :
+                              "selection foreground",
+                color);
 
         switch (param) {
         case 10:
@@ -726,6 +732,16 @@ osc_dispatch(struct terminal *term)
             if (have_alpha)
                 term->colors.alpha = alpha;
             break;
+
+        case 17:
+            term->colors.selection_bg = color;
+            term->colors.use_custom_selection = true;
+            break;
+
+        case 19:
+            term->colors.selection_fg = color;
+            term->colors.use_custom_selection = true;
+            break;
         }
 
         term_damage_view(term);
@@ -836,6 +852,18 @@ osc_dispatch(struct terminal *term)
         term_damage_cursor(term);
         break;
 
+    case 117:
+        LOG_DBG("resetting selection background color");
+        term->colors.selection_bg = term->conf->colors.selection_bg;
+        term->colors.use_custom_selection = term->conf->colors.use_custom.selection;
+        break;
+
+    case 119:
+        LOG_DBG("resetting selection foreground color");
+        term->colors.selection_fg = term->conf->colors.selection_fg;
+        term->colors.use_custom_selection = term->conf->colors.use_custom.selection;
+        break;
+
     case 555:
         osc_flash(term);
         break;

render.c

@@ -416,9 +416,9 @@ render_cell(struct terminal *term, pixman_image_t *pix,
     uint32_t _fg = 0;
     uint32_t _bg = 0;
 
-    if (is_selected && term->conf->colors.use_custom.selection) {
+    if (is_selected && term->colors.use_custom_selection) {
-        _fg = term->conf->colors.selection_fg;
+        _fg = term->colors.selection_fg;
-        _bg = term->conf->colors.selection_bg;
+        _bg = term->colors.selection_bg;
     } else {
         /* Use cell specific color, if set, otherwise the default colors (possible reversed) */
         _fg = cell->attrs.have_fg ? cell->attrs.fg : term->colors.fg;

terminal.c

@@ -1087,6 +1087,9 @@ term_init(const struct config *conf, struct fdm *fdm, struct reaper *reaper,
             .fg = conf->colors.fg,
             .bg = conf->colors.bg,
             .alpha = conf->colors.alpha,
+            .selection_fg = conf->colors.selection_fg,
+            .selection_bg = conf->colors.selection_bg,
+            .use_custom_selection = conf->colors.use_custom.selection,
         },
         .origin = ORIGIN_ABSOLUTE,
         .cursor_style = conf->cursor.style,
@@ -1683,6 +1686,9 @@ term_reset(struct terminal *term, bool hard)
     term->colors.fg = term->conf->colors.fg;
     term->colors.bg = term->conf->colors.bg;
     term->colors.alpha = term->conf->colors.alpha;
+    term->colors.selection_fg = term->conf->colors.selection_fg;
+    term->colors.selection_bg = term->conf->colors.selection_bg;
+    term->colors.use_custom_selection = term->conf->colors.use_custom.selection;
     memcpy(term->colors.table, term->conf->colors.table,
            sizeof(term->colors.table));
     term->origin = ORIGIN_ABSOLUTE;

terminal.h

@@ -407,6 +407,9 @@ struct terminal {
         uint32_t bg;
         uint32_t table[256];
         uint16_t alpha;
+        uint32_t selection_fg;
+        uint32_t selection_bg;
+        bool use_custom_selection;
     } colors;
 
     enum cursor_style cursor_style;