Add options for custom background colors

config.c

@@ -1388,6 +1388,15 @@ parse_color_theme(struct context *ctx, struct color_theme *theme)
         return true;
     }
 
+    else if (key_len == 11 && str_has_prefix(key, "background") && last_digit < 8)
+    {
+        if (!value_to_color(ctx, &theme->background[last_digit], false))
+            return false;
+
+        theme->use_custom.background |= 1 << last_digit;
+        return true;
+    }
+
     else if (str_has_prefix(key, "sixel") &&
              ((key_len == 6 && last_digit < 10) ||
               (key_len == 7 && key[5] == '1' && last_digit < 6)))

config.h

@@ -143,6 +143,7 @@ struct color_theme {
     uint32_t url;
 
     uint32_t dim[8];
+    uint32_t background[8];
     uint32_t sixel[16];
 
     enum {
@@ -186,6 +187,7 @@ struct color_theme {
         bool search_box_no_match:1;
         bool search_box_match:1;
         uint8_t dim;
+        uint8_t background;
     } use_custom;
 };
 

doc/foot.ini.5.scd

@@ -1017,6 +1017,14 @@ dark theme (since the default theme is dark).
 	_e9e836_, _5dc5f8_, _feabf2_, _24dfc4_, _ffffff_ (starlight
 	theme, V4).
 
+*background0*, *background1* *..* *background7*
+	Custom colors to use for background colors. By default the eight
+	foreground colors are used.
+
+	Note that applications can change the *regularN* colors at runtime
+	which affects the background colors when *backgroundN* is not
+	defined.
+
 *dim0*, *dim1* *..* *dim7*
 	Custom colors to use with dimmed colors. Dimmed colors do not have
 	an entry in the color palette. Applications emit them by combining

foot.ini

@@ -134,6 +134,16 @@
 # ...
 # dim7=<not-set>
 
+## custom background colors (see foot.ini(5) man page)
+# background0=<not set>  # black
+# background1=<not set>  # red
+# background2=<not set>  # green
+# background3=<not set>  # yellow
+# background4=<not set>  # blue
+# background5=<not set>  # magenta
+# background6=<not set>  # cyan
+# background7=<not set>  # white
+
 ## The remaining 256-color palette
 # 16 = <256-color palette #16>
 # ...

render.c

@@ -725,7 +725,10 @@ render_cell(struct terminal *term, pixman_image_t *pix,
     case COLOR_BASE16:
     case COLOR_BASE256:
         xassert(cell->attrs.bg < ALEN(term->colors.table));
-        _bg = term->colors.table[cell->attrs.bg];
+        if (cell->attrs.bg < 8 && term->conf->colors.use_custom.background & (1 << cell->attrs.bg))
+            _bg = term->conf->colors.background[cell->attrs.bg];
+        else
+            _bg = term->colors.table[cell->attrs.bg];
         break;
 
     case COLOR_DEFAULT: