[gnome-text-editor] recoloring: use text fg/bg when possible

[Christian Hergert <chergert src gnome org>]

commit 3f4da6c7227d773d40c5f4ae7b9101708e34bf32
Author: Christian Hergert <chergert redhat com>
Date:   Thu Jan 13 11:00:16 2022 -0800

    recoloring: use text fg/bg when possible
    
    If we have values for both fg and bg of text, we should just apply that
    to the window/headerbar to ensure we have reasonable contrast as would be
    expected by the scheme.
    
    If this isn't good enough contrast, we should blame the style scheme and
    fix things there.
    
    Fixes #286

 src/editor-recoloring.c | 36 ++++++++++++++++++++++++------------
 1 file changed, 24 insertions(+), 12 deletions(-)
---
diff --git a/src/editor-recoloring.c b/src/editor-recoloring.c
index dd1ac80..1580901 100644
--- a/src/editor-recoloring.c
+++ b/src/editor-recoloring.c
@@ -225,6 +225,8 @@ _editor_recoloring_generate_css (GtkSourceStyleScheme *style_scheme)
   GString *str;
   GdkRGBA color;
   gboolean is_dark;
+  gboolean has_fg;
+  gboolean has_bg;
 
   g_return_val_if_fail (GTK_SOURCE_IS_STYLE_SCHEME (style_scheme), NULL);
 
@@ -242,22 +244,32 @@ _editor_recoloring_generate_css (GtkSourceStyleScheme *style_scheme)
 
   /* TODO: Improve error checking and fallbacks */
 
-  get_background (style_scheme, "text", &text_bg);
-  get_foreground (style_scheme, "text", &text_fg);
+  has_bg = get_background (style_scheme, "text", &text_bg);
+  has_fg = get_foreground (style_scheme, "text", &text_fg);
   get_background (style_scheme, "right-margin", &right_margin);
   right_margin.alpha = 1;
 
-  if (is_dark)
-    define_color_mixed (str, "window_bg_color", &text_bg, alt, .025);
-  else
-    define_color_mixed (str, "window_bg_color", &text_bg, &white, .1);
-  define_color_mixed (str, "window_fg_color", &text_fg, alt, .1);
-
-  if (is_dark)
-    define_color_mixed (str, "headerbar_bg_color", &text_bg, alt, .05);
+  if (has_fg && has_bg)
+    {
+      define_color (str, "window_bg_color", &text_bg);
+      define_color (str, "window_fg_color", &text_fg);
+      define_color (str, "headerbar_bg_color", &text_bg);
+      define_color (str, "headerbar_fg_color", &text_fg);
+    }
   else
-    define_color_mixed (str, "headerbar_bg_color", &text_bg, alt, .025);
-  define_color (str, "headerbar_fg_color", &text_fg);
+    {
+      if (is_dark)
+        define_color_mixed (str, "window_bg_color", &text_bg, alt, .025);
+      else
+        define_color_mixed (str, "window_bg_color", &text_bg, &white, .1);
+      define_color_mixed (str, "window_fg_color", &text_fg, alt, .1);
+
+      if (is_dark)
+        define_color_mixed (str, "headerbar_bg_color", &text_bg, alt, .05);
+      else
+        define_color_mixed (str, "headerbar_bg_color", &text_bg, alt, .025);
+      define_color (str, "headerbar_fg_color", &text_fg);
+    }
 
   define_color_mixed (str, "view_bg_color", &text_bg, &white, is_dark ? .1 : .3);
   define_color (str, "view_fg_color", &text_fg);