Revert usage of CoreText in ATSUI backend

Next to CGFontRef we also store an ATSFontRef now.  This required
the addition of the public for backends function
pango_atsui_font_get_atsfont().  I have marked this call to be available
starting version 1.27, as Pango is now in the midst of the 1.26 series.

Since we now store the ATSFontRef next to CGFontRef, we can continue to
make use of the ATS API in
pango_cairo_atsui_font_create_metrics_for_context().  The CoreText calls
have been removed.  Both Tiger and earlier, and Leopard and later machines
will now use the ATS API.

It is well known that the ATS API has been deprecated in Leopard.  In the
near future a brand-new CoreText backend has to be written (from scratch)
that should be installed and used on Macs running Leopard and later.

This patch has been tested on 32-bit Tiger and 64-bit Snow Leopard and
found to be functioning correctly.  The build should now work again fine
on Tiger machines, as it has been broken since the introduction of the
CoreText calls.

4 files changed, 44 insertions, 14 deletions

diff --git a/pango/pangoatsui-private.h b/pango/pangoatsui-private.h
index 8c734f00..a5ab0cb7 100644
--- a/pango/pangoatsui-private.h
+++ b/pango/pangoatsui-private.h
@@ -95,6 +95,8 @@ void                  _pango_atsui_font_set_context_key      (PangoATSUIFont
                                                               gpointer           context_key);
 void                  _pango_atsui_font_set_cgfont           (PangoATSUIFont    *font,
                                                               CGFontRef         font_id);
+void                  _pango_atsui_font_set_atsfont          (PangoATSUIFont    *font,
+                                                              ATSFontRef        font_ref);
 
 G_END_DECLS
 
diff --git a/pango/pangoatsui.c b/pango/pangoatsui.c
index 6aa970ed..e8029559 100644
--- a/pango/pangoatsui.c
+++ b/pango/pangoatsui.c
@@ -33,6 +33,7 @@ struct _PangoATSUIFontPrivate
   gpointer context_key;
 
   CGFontRef font_id;
+  ATSFontRef font_ref;
 
   PangoFontMap *fontmap;
 };
@@ -177,13 +178,22 @@ _pango_atsui_font_set_context_key (PangoATSUIFont *afont,
 
 void
 _pango_atsui_font_set_cgfont (PangoATSUIFont *font,
-                                    CGFontRef      font_id)
+                              CGFontRef      font_id)
 {
   PangoATSUIFontPrivate *priv = font->priv;
 
   priv->font_id = font_id;
 }
 
+void
+_pango_atsui_font_set_atsfont (PangoATSUIFont *font,
+                               ATSFontRef      font_ref)
+{
+  PangoATSUIFontPrivate *priv = font->priv;
+
+  priv->font_ref = font_ref;
+}
+
 /**
  * pango_atsui_font_get_cgfont:
  * @font: A #PangoATSUIFont
@@ -201,3 +211,21 @@ pango_atsui_font_get_cgfont (PangoATSUIFont *font)
 
   return priv->font_id;
 }
+
+/**
+ * pango_atsui_font_get_atsfont:
+ * @font: A #PangoATSUIFont
+ *
+ * Returns the ATSFontRef of a font.
+ *
+ * Return value: the ATSFontRef associated to @font.
+ *
+ * Since: 1.27
+ */
+ATSFontRef
+pango_atsui_font_get_atsfont (PangoATSUIFont *font)
+{
+  PangoATSUIFontPrivate *priv = font->priv;
+
+  return priv->font_ref;
+}
diff --git a/pango/pangoatsui.h b/pango/pangoatsui.h
index 12db6de3..3ca558e2 100644
--- a/pango/pangoatsui.h
+++ b/pango/pangoatsui.h
@@ -68,7 +68,8 @@ struct _PangoATSUIFontClass
 
 #endif /* PANGO_ENABLE_BACKEND */
 
-CGFontRef pango_atsui_font_get_cgfont (PangoATSUIFont *font);
+CGFontRef  pango_atsui_font_get_cgfont  (PangoATSUIFont *font);
+ATSFontRef pango_atsui_font_get_atsfont (PangoATSUIFont *font);
 
 #endif /* PANGO_ENABLE_ENGINE || PANGO_ENABLE_BACKEND */
 
diff --git a/pango/pangocairo-atsuifont.c b/pango/pangocairo-atsuifont.c
index 91391e7e..057cc76c 100644
--- a/pango/pangocairo-atsuifont.c
+++ b/pango/pangocairo-atsuifont.c
@@ -119,8 +119,8 @@ pango_cairo_atsui_font_create_metrics_for_context (PangoCairoFont *font,
 {
   PangoCairoATSUIFont *cafont = (PangoCairoATSUIFont *) font;
   PangoATSUIFont *afont = (PangoATSUIFont *) font;
-  CGFontRef cg_font;
-  CTFontRef ct_font;
+  ATSFontRef ats_font;
+  ATSFontMetrics ats_metrics;
   PangoFontMetrics *metrics;
   PangoFontDescription *font_desc;
   PangoLayout *layout;
@@ -128,19 +128,19 @@ pango_cairo_atsui_font_create_metrics_for_context (PangoCairoFont *font,
   PangoLanguage *language = pango_context_get_language (context);
   const char *sample_str = pango_language_get_sample_string (language);
 
-  cg_font = pango_atsui_font_get_cgfont (afont);
-  ct_font = CTFontCreateWithGraphicsFont(cg_font, cafont->size, NULL, NULL);
-
   metrics = pango_font_metrics_new ();
 
-  metrics->ascent = CTFontGetAscent(ct_font) * PANGO_SCALE;
-  metrics->descent = CTFontGetDescent(ct_font) * PANGO_SCALE;
+  ats_font = pango_atsui_font_get_atsfont (afont);
+  ATSFontGetHorizontalMetrics (ats_font, kATSOptionFlagsDefault, &ats_metrics);
+
+  metrics->ascent = ats_metrics.ascent * cafont->size * PANGO_SCALE;
+  metrics->descent = -ats_metrics.descent * cafont->size * PANGO_SCALE;
 
-  metrics->underline_position = CTFontGetUnderlinePosition(ct_font) * PANGO_SCALE;
-  metrics->underline_thickness = CTFontGetUnderlineThickness(ct_font) * PANGO_SCALE;
+  metrics->underline_position = ats_metrics.underlinePosition * cafont->size * PANGO_SCALE;
+  metrics->underline_thickness = ats_metrics.underlineThickness * cafont->size * PANGO_SCALE;
 
   metrics->strikethrough_position = metrics->ascent / 3;
-  metrics->strikethrough_thickness = metrics->underline_thickness * PANGO_SCALE;
+  metrics->strikethrough_thickness = ats_metrics.underlineThickness * cafont->size * PANGO_SCALE;
 
   layout = pango_layout_new (context);
   font_desc = pango_font_describe_with_absolute_size ((PangoFont *) font);
@@ -155,8 +155,6 @@ pango_cairo_atsui_font_create_metrics_for_context (PangoCairoFont *font,
 
   pango_font_description_free (font_desc);
   g_object_unref (layout);
-  
-  
 
   return metrics;
 }
@@ -270,6 +268,7 @@ _pango_cairo_atsui_font_new (PangoCairoATSUIFontMap     *cafontmap,
 
   size = (double) pango_font_description_get_size (desc) / PANGO_SCALE;
   _pango_atsui_font_set_cgfont (afont, font_id);
+  _pango_atsui_font_set_atsfont (afont, font_ref);
 
   if (context)
     {