syntax.c: Support bg/fg special color-names. #5319

Refresh colors if changing Normal group

1 files changed, 24 insertions, 0 deletions

diff --git a/src/nvim/syntax.c b/src/nvim/syntax.c
index bec2b5c5b0..c753c6fabd 100644
--- a/src/nvim/syntax.c
+++ b/src/nvim/syntax.c
@@ -6597,6 +6597,9 @@ do_highlight (
   else {
     if (is_normal_group) {
       HL_TABLE()[idx].sg_attr = 0;
+      // Need to update all groups, because they might be using "bg" and/or
+      // "fg", which have been changed now.
+      highlight_attr_set_all();
       // If the normal group has changed, it is simpler to refresh every UI
       ui_refresh();
     } else
@@ -7261,6 +7264,23 @@ int syn_get_final_id(int hl_id)
   return hl_id;
 }
 
+/// Refresh the color attributes of all highlight groups.
+static void highlight_attr_set_all(void)
+{
+  for (int idx = 0; idx < highlight_ga.ga_len; idx++) {
+    struct hl_group *sgp = &HL_TABLE()[idx];
+    if (sgp->sg_rgb_bg_name != NULL) {
+      sgp->sg_rgb_bg = name_to_color(sgp->sg_rgb_bg_name);
+    }
+    if (sgp->sg_rgb_fg_name != NULL) {
+      sgp->sg_rgb_fg = name_to_color(sgp->sg_rgb_fg_name);
+    }
+    if (sgp->sg_rgb_sp_name != NULL) {
+      sgp->sg_rgb_sp = name_to_color(sgp->sg_rgb_sp_name);
+    }
+    set_hl_attr(idx);
+  }
+}
 
 /*
  * Translate the 'highlight' option into attributes in highlight_attr[] and
@@ -7702,6 +7722,10 @@ RgbValue name_to_color(uint8_t *name)
       && isxdigit(name[6]) && name[7] == NUL) {
     // rgb hex string
     return strtol((char *)(name + 1), NULL, 16);
+  } else if (!STRICMP(name, "bg") || !STRICMP(name, "background")) {
+    return normal_bg;
+  } else if (!STRICMP(name, "fg") || !STRICMP(name, "foreground")) {
+    return normal_fg;
   }
 
   for (int i = 0; color_name_table[i].name != NULL; i++) {