Merge branch 'color-stack'

Closes #856

CHANGELOG.md

@@ -63,10 +63,14 @@
 * Support for high-res mouse wheel scroll events ([#1738][1738]).
 * Styled and colored underlines ([#828][828]).
 * Support for SGR 21 (double underline).
+* Support for `XTPUSHCOLORS`, `XTPOPCOLORS` and `XTREPORTCOLORS`,
+  i.e. color palette stack ([#856][856]).
 
 [1707]: https://codeberg.org/dnkl/foot/issues/1707
 [1738]: https://codeberg.org/dnkl/foot/issues/1738
 [828]: https://codeberg.org/dnkl/foot/issues/828
+[856]: https://codeberg.org/dnkl/foot/issues/856
+
 
 ### Changed
 

csi.c

@@ -2048,6 +2048,83 @@ csi_dispatch(struct terminal *term, uint8_t final)
         break; /* private[0] == ‘$’ */
     }
 
+    case '#': {
+        switch (final) {
+        case 'P': { /* XTPUSHCOLORS */
+            int slot = vt_param_get(term, 0, 0);
+
+            /* Pm == 0, "push" (what xterm does is take take the
+               *current* slot + 1, even if that's in the middle of the
+               stack, and overwrites whatever is already in that
+               slot) */
+            if (slot == 0)
+                slot = term->color_stack.idx + 1;
+
+            if (term->color_stack.size < slot) {
+                const size_t new_size = slot;
+                term->color_stack.stack = xrealloc(
+                    term->color_stack.stack,
+                    new_size * sizeof(term->color_stack.stack[0]));
+
+                /* Initialize new slots (except the selected slot,
+                   which is done below) */
+                xassert(new_size > 0);
+                for (size_t i = term->color_stack.size; i < new_size - 1; i++) {
+                    memcpy(&term->color_stack.stack[i], &term->colors,
+                           sizeof(term->colors));
+                }
+                term->color_stack.size = new_size;
+            }
+
+            xassert(slot > 0);
+            xassert(slot <= term->color_stack.size);
+            term->color_stack.idx = slot;
+            memcpy(&term->color_stack.stack[slot - 1], &term->colors,
+                   sizeof(term->colors));
+            break;
+        }
+
+        case 'Q': {  /* XTPOPCOLORS */
+            int slot = vt_param_get(term, 0, 0);
+
+            /* Pm == 0, "pop" (what xterm does is copy colors from the
+              *current* slot, *and* decrease the current slot index,
+              even if that's in the middle of the stack) */
+            if (slot == 0)
+                slot = term->color_stack.idx;
+
+            if (slot > 0 && slot <= term->color_stack.size) {
+                memcpy(&term->colors, &term->color_stack.stack[slot - 1],
+                       sizeof(term->colors));
+                term->color_stack.idx = slot - 1;
+
+                /* TODO: we _could_ iterate all cells and only dirty
+                   those that are affected by the palette change... */
+                term_damage_view(term);
+                term_damage_margins(term);
+            } else if (slot == 0) {
+                LOG_ERR("XTPOPCOLORS: cannot pop beyond the first element");
+            } else {
+                LOG_ERR(
+                    "XTPOPCOLORS: invalid color slot: %d "
+                    "(stack has %zu slots, current slot is %zu)",
+                    vt_param_get(term, 0, 0),
+                    term->color_stack.size, term->color_stack.idx);
+            }
+            break;
+        }
+
+        case 'R': {  /* XTREPORTCOLORS */
+            char reply[64];
+            int n = xsnprintf(reply, sizeof(reply), "\033[?%zu;%zu#Q",
+                              term->color_stack.idx, term->color_stack.size);
+            term_to_slave(term, reply, n);
+            break;
+        }
+        }
+        break; /* private[0] == '#' */
+    }
+
     case 0x243f:  /* ?$ */
         switch (final) {
         case 'p': {

doc/foot-ctlseqs.7.scd

@@ -632,6 +632,19 @@ manipulation sequences. The generic format is:
 :  <unnamed>
 :  kitty
 :  Update current Kitty keyboard flags, according to _mode_.
+|  \\E[ # P
+:  XTPUSHCOLORS
+:  xterm
+:  Push current color palette onto stack
+|  \\E[ # Q
+:  XTPOPCOLORS
+:  xterm
+:  Pop color palette from stack
+|  \\E[ # R
+:  XTREPORTCOLORS
+:  xterm
+:  Report the current entry on the palette stack, and the number of
+   palettes stored on the stack.
 
 
 # OSC

osc.c

@@ -712,15 +712,25 @@ osc_dispatch(struct terminal *term)
         osc_notify(term, string);
         break;
 
-    case 10:
+    case 10:    /* fg */
-    case 11:
+    case 11:    /* bg */
-    case 17:
+    case 12:    /* cursor */
-    case 19: {
+    case 17:    /* highlight (selection) fg */
+    case 19: {  /* highlight (selection) bg */
         /* Set default foreground/background/highlight-bg/highlight-fg color */
 
         /* Client queried for current value */
         if (string[0] == '?' && string[1] == '\0') {
-            uint32_t color = param == 10 ? term->colors.fg : term->colors.bg;
+            uint32_t color = param == 10
+                ? term->colors.fg
+                : param == 11
+                    ? term->colors.bg
+                    : param == 12
+                        ? term->colors.cursor_bg
+                        : param == 17
+                            ? term->colors.selection_bg
+                            : term->colors.selection_fg;
+
             uint8_t r = (color >> 16) & 0xff;
             uint8_t g = (color >>  8) & 0xff;
             uint8_t b = (color >>  0) & 0xff;
@@ -754,6 +764,7 @@ osc_dispatch(struct terminal *term)
         LOG_DBG("change color definition for %s to %06x",
                 param == 10 ? "foreground" :
                 param == 11 ? "background" :
+                param == 12 ? "cursor" :
                 param == 17 ? "selection background" :
                               "selection foreground",
                 color);
@@ -761,6 +772,7 @@ osc_dispatch(struct terminal *term)
         switch (param) {
         case 10:
             term->colors.fg = color;
+            term_damage_view(term);
             break;
 
         case 11:
@@ -774,61 +786,31 @@ osc_dispatch(struct terminal *term)
                     term_font_subpixel_changed(term);
                 }
             }
+            term_damage_view(term);
+            term_damage_margins(term);
+            break;
+
+        case 12:
+            term->colors.cursor_bg = 1u << 31 | color;
+            term_damage_cursor(term);
             break;
 
         case 17:
             term->colors.selection_bg = color;
             term->colors.use_custom_selection = true;
+            term_damage_view(term);
             break;
 
         case 19:
             term->colors.selection_fg = color;
             term->colors.use_custom_selection = true;
+            term_damage_view(term);
             break;
         }
 
-        term_damage_view(term);
-        term_damage_margins(term);
         break;
     }
 
-    case 12: /* Set cursor color */
-
-        /* Client queried for current value */
-        if (string[0] == '?' && string[1] == '\0') {
-            uint8_t r = (term->cursor_color.cursor >> 16) & 0xff;
-            uint8_t g = (term->cursor_color.cursor >>  8) & 0xff;
-            uint8_t b = (term->cursor_color.cursor >>  0) & 0xff;
-            const char *terminator = term->vt.osc.bel ? "\a" : "\033\\";
-
-            char reply[32];
-            size_t n = xsnprintf(
-                reply, sizeof(reply), "\033]12;rgb:%02x/%02x/%02x%s",
-                r, g, b, terminator);
-
-            term_to_slave(term, reply, n);
-            break;
-        }
-
-        uint32_t color;
-
-        if (string[0] == '#' || string[0] == '['
-            ? !parse_legacy_color(string, &color, NULL, NULL)
-            : !parse_rgb(string, &color, NULL, NULL))
-        {
-            break;
-        }
-
-        LOG_DBG("change cursor color to %06x", color);
-
-        if (color == 0)
-            term->cursor_color.cursor = 0;  /* Invert fg/bg */
-        else
-            term->cursor_color.cursor = 1u << 31 | color;
-
-        term_damage_cursor(term);
-        break;
-
     case 22:  /* Set mouse cursor */
         term_set_user_mouse_cursor(term, string);
         break;
@@ -895,8 +877,8 @@ osc_dispatch(struct terminal *term)
 
     case 112:
         LOG_DBG("resetting cursor color");
-        term->cursor_color.text = term->conf->cursor.color.text;
+        term->colors.cursor_fg = term->conf->cursor.color.text;
-        term->cursor_color.cursor = term->conf->cursor.color.cursor;
+        term->colors.cursor_bg = term->conf->cursor.color.cursor;
         term_damage_cursor(term);
         break;
 

render.c

@@ -557,13 +557,13 @@ cursor_colors_for_cell(const struct terminal *term, const struct cell *cell,
               const pixman_color_t *fg, const pixman_color_t *bg,
               pixman_color_t *cursor_color, pixman_color_t *text_color)
 {
-    if (term->cursor_color.cursor >> 31)
+    if (term->colors.cursor_bg >> 31)
-        *cursor_color = color_hex_to_pixman(term->cursor_color.cursor);
+        *cursor_color = color_hex_to_pixman(term->colors.cursor_bg);
     else
         *cursor_color = *fg;
 
-    if (term->cursor_color.text >> 31)
+    if (term->colors.cursor_fg >> 31)
-        *text_color = color_hex_to_pixman(term->cursor_color.text);
+        *text_color = color_hex_to_pixman(term->colors.cursor_fg);
     else {
         *text_color = *bg;
 

terminal.c

@@ -1221,10 +1221,17 @@ term_init(const struct config *conf, struct fdm *fdm, struct reaper *reaper,
             .fg = conf->colors.fg,
             .bg = conf->colors.bg,
             .alpha = conf->colors.alpha,
+            .cursor_fg = conf->cursor.color.text,
+            .cursor_bg = conf->cursor.color.cursor,
             .selection_fg = conf->colors.selection_fg,
             .selection_bg = conf->colors.selection_bg,
             .use_custom_selection = conf->colors.use_custom.selection,
         },
+        .color_stack = {
+            .stack = NULL,
+            .size = 0,
+            .idx = 0,
+        },
         .origin = ORIGIN_ABSOLUTE,
         .cursor_style = conf->cursor.style,
         .cursor_blink = {
@@ -1233,10 +1240,6 @@ term_init(const struct config *conf, struct fdm *fdm, struct reaper *reaper,
             .state = CURSOR_BLINK_ON,
             .fd = -1,
         },
-        .cursor_color = {
-            .text = conf->cursor.color.text,
-            .cursor = conf->cursor.color.cursor,
-        },
         .selection = {
             .coords = {
                 .start = {-1, -1},
@@ -1825,6 +1828,7 @@ term_destroy(struct terminal *term)
     free(term->foot_exe);
     free(term->cwd);
     free(term->mouse_user_cursor);
+    free(term->color_stack.stack);
 
     int ret = EXIT_SUCCESS;
 
@@ -2035,11 +2039,17 @@ 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.cursor_fg = term->conf->cursor.color.text;
+    term->colors.cursor_bg = term->conf->cursor.color.cursor;
     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));
+    free(term->color_stack.stack);
+    term->color_stack.stack = NULL;
+    term->color_stack.size = 0;
+    term->color_stack.idx = 0;
     term->origin = ORIGIN_ABSOLUTE;
     term->normal.cursor.lcf = false;
     term->alt.cursor.lcf = false;
@@ -2051,8 +2061,6 @@ term_reset(struct terminal *term, bool hard)
     term->cursor_blink.decset = false;
     term->cursor_blink.deccsusr = term->conf->cursor.blink.enabled;
     term_cursor_blink_update(term);
-    term->cursor_color.text = term->conf->cursor.color.text;
-    term->cursor_color.cursor = term->conf->cursor.color.cursor;
     selection_cancel(term);
     term->normal.offset = term->normal.view = 0;
     term->alt.offset = term->alt.view = 0;

terminal.h

@@ -393,6 +393,19 @@ struct url {
 };
 typedef tll(struct url) url_list_t;
 
+
+struct colors {
+    uint32_t fg;
+    uint32_t bg;
+    uint32_t table[256];
+    uint16_t alpha;
+    uint32_t cursor_fg;  /* Text color */
+    uint32_t cursor_bg;  /* cursor color */
+    uint32_t selection_fg;
+    uint32_t selection_bg;
+    bool use_custom_selection;
+};
+
 struct terminal {
     struct fdm *fdm;
     struct reaper *reaper;
@@ -563,15 +576,13 @@ struct terminal {
     int cell_width;  /* pixels per cell, x-wise */
     int cell_height; /* pixels per cell, y-wise */
 
+    struct colors colors;
+
     struct {
-        uint32_t fg;
+        struct colors *stack;
-        uint32_t bg;
+        size_t idx;
-        uint32_t table[256];
+        size_t size;
-        uint16_t alpha;
+    } color_stack;
-        uint32_t selection_fg;
-        uint32_t selection_bg;
-        bool use_custom_selection;
-    } colors;
 
     enum cursor_style cursor_style;
     struct {
@@ -580,10 +591,6 @@ struct terminal {
         int fd;
         enum { CURSOR_BLINK_ON, CURSOR_BLINK_OFF } state;
     } cursor_blink;
-    struct {
-        uint32_t text;
-        uint32_t cursor;
-    } cursor_color;
 
     struct {
         enum selection_kind kind;