PangoCairo: Create cairo_font_face_t using DirectWrite

...if Cairo is built with DirectWrite support.  With this, we can
support colored Emoji, a long-standing issue, on Windows without needing
to use FontConfig, on Windows 8.1 or later, since DirectWrite added support
for colored Emoji starting with Windows 8.1.

This will really fix issue !302 completely, regarding the Emoji not
shown in color!

1 files changed, 26 insertions, 0 deletions

diff --git a/pango/pangocairo-win32font.c b/pango/pangocairo-win32font.c
index 5b860bab..0141c414 100644
--- a/pango/pangocairo-win32font.c
+++ b/pango/pangocairo-win32font.c
@@ -75,6 +75,32 @@ pango_cairo_win32_font_create_font_face (PangoCairoFont *font)
 {
   PangoCairoWin32Font *cwfont = PANGO_CAIRO_WIN32_FONT (font);
   PangoWin32Font *win32font =  &cwfont->font;
+  void *dwrite_font_face = NULL;
+  gpointer dwrite_font = NULL;
+
+#ifdef HAVE_CAIRO_WIN32_DIRECTWRITE
+  dwrite_font_face = pango_win32_font_get_dwrite_font_face (win32font);
+  if (dwrite_font_face != NULL)
+    {
+      cairo_font_face_t *cairo_face = cairo_dwrite_font_face_create_for_dwrite_fontface (dwrite_font_face);
+
+      if (cairo_face != NULL)
+        {
+          static const cairo_user_data_key_t key;
+
+          cairo_font_face_set_user_data (cairo_face, &key,
+                                         dwrite_font_face,
+                                         (cairo_destroy_func_t) pango_win32_dwrite_font_face_release);
+
+          return cairo_face;
+        }
+      else
+        {
+          g_warning ("cairo_font_face creation failed with DirectWrite, fallback to GDI");
+          pango_win32_dwrite_font_face_release (dwrite_font_face);
+        }
+    }
+#endif
 
   return cairo_win32_font_face_create_for_logfontw (&win32font->logfontw);
 }