[mutter/wip/carlosg/pango-renderer-color-glyphs: 2/2] cogl-pango: Make color glyphs unaffected by foreground color

[Carlos Garnacho <carlosg src gnome org>]

commit 49df668639e2d79b0823ec3f44de11282846d0c3
Author: Carlos Garnacho <carlosg gnome org>
Date:   Wed Mar 25 00:29:19 2020 +0100

    cogl-pango: Make color glyphs unaffected by foreground color
    
    Making color glyphs affected by the foreground color makes them become
    "tinted" on any other color than white. Make it sure we always paint
    those white by checking the cached glyph value, the foreground color
    will be reset on the next iteration through glyphs.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/issues/850
    
    https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1148

 cogl/cogl-pango/cogl-pango-render.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)
---
diff --git a/cogl/cogl-pango/cogl-pango-render.c b/cogl/cogl-pango/cogl-pango-render.c
index d1ef39cb0..7a19f2d8f 100644
--- a/cogl/cogl-pango/cogl-pango-render.c
+++ b/cogl/cogl-pango/cogl-pango-render.c
@@ -841,14 +841,13 @@ cogl_pango_renderer_draw_glyphs (PangoRenderer    *renderer,
   CoglPangoGlyphCacheValue *cache_value;
   int i;
 
-  cogl_pango_renderer_set_color_for_part (renderer,
-                                         PANGO_RENDER_PART_FOREGROUND);
-
   for (i = 0; i < glyphs->num_glyphs; i++)
     {
       PangoGlyphInfo *gi = glyphs->glyphs + i;
       float x, y;
 
+      cogl_pango_renderer_set_color_for_part (renderer,
+                                              PANGO_RENDER_PART_FOREGROUND);
       cogl_pango_renderer_get_device_units (renderer,
                                            xi + gi->geometry.x_offset,
                                            yi + gi->geometry.y_offset,
@@ -905,6 +904,15 @@ cogl_pango_renderer_draw_glyphs (PangoRenderer    *renderer,
              x += (float)(cache_value->draw_x);
              y += (float)(cache_value->draw_y);
 
+              /* Do not override color if the glyph/font provide its own */
+              if (cache_value->has_color)
+                {
+                  CoglColor color;
+
+                  cogl_color_init_from_4ub (&color, 0xff, 0xff, 0xff, 0xff);
+                  _cogl_pango_display_list_set_color_override (priv->display_list, &color);
+                }
+
               cogl_pango_renderer_draw_glyph (priv, cache_value, x, y);
            }
        }