[mutter/wip/carlosg/pango-renderer-color-glyphs: 1/2] cogl-pango: Cache whether glyphs are backed up by a color font

[Carlos Garnacho <carlosg src gnome org>]

commit a2d2c01a09aa16867529994a5da937cdd0590970
Author: Carlos Garnacho <carlosg gnome org>
Date:   Wed Mar 25 00:28:30 2020 +0100

    cogl-pango: Cache whether glyphs are backed up by a color font
    
    This will be necessary later on.
    
    https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1148

 cogl/cogl-pango/cogl-pango-display-list.c |  1 +
 cogl/cogl-pango/cogl-pango-glyph-cache.h  |  4 +++-
 cogl/cogl-pango/cogl-pango-render.c       | 21 +++++++++++++++++++++
 3 files changed, 25 insertions(+), 1 deletion(-)
---
diff --git a/cogl/cogl-pango/cogl-pango-display-list.c b/cogl/cogl-pango/cogl-pango-display-list.c
index 8615402b9..e4bb1275d 100644
--- a/cogl/cogl-pango/cogl-pango-display-list.c
+++ b/cogl/cogl-pango/cogl-pango-display-list.c
@@ -81,6 +81,7 @@ struct _CoglPangoDisplayListNode
       GArray *rectangles;
       /* A primitive representing those vertices */
       CoglPrimitive *primitive;
+      guint has_color : 1;
     } texture;
 
     struct
diff --git a/cogl/cogl-pango/cogl-pango-glyph-cache.h b/cogl/cogl-pango/cogl-pango-glyph-cache.h
index ec0616acc..0e523184d 100644
--- a/cogl/cogl-pango/cogl-pango-glyph-cache.h
+++ b/cogl/cogl-pango/cogl-pango-glyph-cache.h
@@ -58,7 +58,9 @@ struct _CoglPangoGlyphCacheValue
 
   /* This will be set to TRUE when the glyph atlas is reorganized
      which means the glyph will need to be redrawn */
-  gboolean   dirty;
+  guint dirty : 1;
+  /* Set to TRUE if the glyph has colors (eg. emoji) */
+  guint has_color : 1;
 };
 
 typedef void (* CoglPangoGlyphCacheDirtyFunc) (PangoFont *font,
diff --git a/cogl/cogl-pango/cogl-pango-render.c b/cogl/cogl-pango/cogl-pango-render.c
index dedc0433f..d1ef39cb0 100644
--- a/cogl/cogl-pango/cogl-pango-render.c
+++ b/cogl/cogl-pango/cogl-pango-render.c
@@ -50,6 +50,7 @@
 #include <pango/pangocairo.h>
 #include <pango/pango-renderer.h>
 #include <cairo.h>
+#include <cairo-ft.h>
 
 #include "cogl/cogl-debug.h"
 #include "cogl/cogl-context-private.h"
@@ -526,6 +527,24 @@ cogl_pango_renderer_get_cached_glyph (PangoRenderer *renderer,
                                         create, font, glyph);
 }
 
+static gboolean
+font_has_color_glyphs (const PangoFont *font)
+{
+  cairo_scaled_font_t *scaled_font;
+  gboolean has_color = FALSE;
+
+  scaled_font = pango_cairo_font_get_scaled_font ((PangoCairoFont *) font);
+
+  if (cairo_scaled_font_get_type (scaled_font) == CAIRO_FONT_TYPE_FT)
+    {
+      FT_Face ft_face = cairo_ft_scaled_font_lock_face (scaled_font);
+      has_color = (FT_HAS_COLOR (ft_face) != 0);
+      cairo_ft_scaled_font_unlock_face (scaled_font);
+    }
+
+  return has_color;
+}
+
 static void
 cogl_pango_renderer_set_dirty_glyph (PangoFont *font,
                                      PangoGlyph glyph,
@@ -600,6 +619,8 @@ cogl_pango_renderer_set_dirty_glyph (PangoFont *font,
                            cairo_image_surface_get_data (surface));
 
   cairo_surface_destroy (surface);
+
+  value->has_color = font_has_color_glyphs (font);
 }
 
 static void