Use faces as fonts dictionary keys

Pango faces are just Pango fonts without the size information, it thus avoids
duplication for different sizes. Fortunately, it includes the variant
information.

Author: liZe

weasyprint/pdf/stream.py

@@ -311,11 +311,12 @@ def set_blend_mode(self, mode):
         }))
 
     def add_font(self, pango_font):
-        hb_font = pango.pango_font_get_hb_font(pango_font)
-        hb_face = harfbuzz.hb_font_get_face(hb_font)
-        if pango_font not in self._fonts:
-            self._fonts[pango_font] = Font(pango_font, hb_face)
-        return self._fonts[pango_font]
+        pango_face = pango.pango_font_get_face(pango_font)
+        if pango_face not in self._fonts:
+            hb_font = pango.pango_font_get_hb_font(pango_font)
+            hb_face = harfbuzz.hb_font_get_face(hb_font)
+            self._fonts[pango_face] = Font(pango_font, hb_face)
+        return self._fonts[pango_face]
 
     def add_group(self, bounding_box):
         states = pydyf.Dictionary()

weasyprint/text/ffi.py

@@ -44,6 +44,7 @@
     typedef ... PangoAttrList;
     typedef ... PangoAttrClass;
     typedef ... PangoFont;
+    typedef ... PangoFontFace;
     typedef guint PangoGlyph;
     typedef gint PangoGlyphUnit;
 
@@ -257,6 +258,8 @@
     PangoFontMetrics * pango_context_get_metrics (
         PangoContext *context, const PangoFontDescription *desc,
         PangoLanguage *language);
+    PangoFontMetrics * pango_font_get_metrics (
+        PangoFont *font, PangoLanguage *language);
     void pango_font_metrics_unref (PangoFontMetrics *metrics);
     int pango_font_metrics_get_ascent (PangoFontMetrics *metrics);
     int pango_font_metrics_get_descent (PangoFontMetrics *metrics);
@@ -268,16 +271,12 @@
         PangoFontMetrics *metrics);
     int pango_font_metrics_get_strikethrough_position (
         PangoFontMetrics *metrics);
-
-    void pango_context_set_round_glyph_positions (
-        PangoContext *context, gboolean round_positions);
-
-    PangoFontMetrics * pango_font_get_metrics (
-        PangoFont *font, PangoLanguage *language);
-
     void pango_font_get_glyph_extents (
         PangoFont *font, PangoGlyph glyph, PangoRectangle *ink_rect,
         PangoRectangle *logical_rect);
+    PangoFontFace* pango_font_get_face (PangoFont* font);
+    void pango_context_set_round_glyph_positions (
+        PangoContext *context, gboolean round_positions);
 
     PangoAttrList * pango_attr_list_new (void);
     void pango_attr_list_unref (PangoAttrList *list);