[pango/sort-faces] fc: Sort faces of a family

[Matthias Clasen <matthiasc src gnome org>]

commit c36b573fda672434d8a6c8a2a64a771212c4eead
Author: Matthias Clasen <mclasen redhat com>
Date:   Mon Sep 21 12:52:42 2020 -0400

    fc: Sort faces of a family
    
    Make pango_font_family_list_faces() return faces
    sorted by slant and weight. This makes the font
    chooser look much less random.

 pango/pangofc-fontmap.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)
---
diff --git a/pango/pangofc-fontmap.c b/pango/pangofc-fontmap.c
index e120d305..0f211c46 100644
--- a/pango/pangofc-fontmap.c
+++ b/pango/pangofc-fontmap.c
@@ -2805,6 +2805,32 @@ create_face (PangoFcFamily *fcfamily,
   return face;
 }
 
+static int
+compare_face (const void *p1, const void *p2)
+{
+  const PangoFcFace *f1 = *(const void **)p1;
+  const PangoFcFace *f2 = *(const void **)p2;
+  int w1, w2;
+  int s1, s2;
+
+  if (FcPatternGetInteger (f1->pattern, FC_WEIGHT, 0, &w1) != FcResultMatch)
+    w1 = FC_WEIGHT_MEDIUM;
+
+  if (FcPatternGetInteger (f1->pattern, FC_SLANT, 0, &s1) != FcResultMatch)
+    s1 = FC_SLANT_ROMAN;
+
+  if (FcPatternGetInteger (f2->pattern, FC_WEIGHT, 0, &w2) != FcResultMatch)
+    w2 = FC_WEIGHT_MEDIUM;
+
+  if (FcPatternGetInteger (f2->pattern, FC_SLANT, 0, &s2) != FcResultMatch)
+    s2 = FC_SLANT_ROMAN;
+
+  if (s1 != s2)
+    return s1 - s2; /* roman < italic < oblique */
+
+  return w1 - w2; /* from light to heavy */
+}
+
 static void
 ensure_faces (PangoFcFamily *fcfamily)
 {
@@ -2914,6 +2940,8 @@ ensure_faces (PangoFcFamily *fcfamily)
 
          faces = g_renew (PangoFcFace *, faces, num);
 
+          qsort (faces, num, sizeof (PangoFcFace *), compare_face);
+
          fcfamily->n_faces = num;
          fcfamily->faces = faces;
        }