Implement the get_variation_glyphs method for FreeType >= 2.3.6

* configure.ac: Check availability of FT_Face_GetCharVariantIndex.

* src/ftfont.c (ftfont_variation_glyphs) [HAVE_FT_FACE_GETCHARVARIANTINDEX]:
Add function implementation.

* src/ftcrfont.c (ftcrfont_variation_glyphs)
[HAVE_FT_FACE_GETCHARVARIANTINDEX]: Use function implementation for
HAVE_OTF_GET_VARIATION_GLYPHS.

* src/ftfont.c (ftfont_driver) [HAVE_FT_FACE_GETCHARVARIANTINDEX]:
* src/xftfont.c (xftfont_driver) [HAVE_FT_FACE_GETCHARVARIANTINDEX]:
* src/ftxfont.c (ftxfont_driver) [HAVE_FT_FACE_GETCHARVARIANTINDEX]:
* src/ftcrfont.c (ftcrfont_driver) [HAVE_FT_FACE_GETCHARVARIANTINDEX]:
Populate the get_variation_glyphs method.

4 files changed, 30 insertions, 10 deletions

diff --git a/src/ftcrfont.c b/src/ftcrfont.c
index 0c3b74ff289..1c28a7ceb67 100644
--- a/src/ftcrfont.c
+++ b/src/ftcrfont.c
@@ -455,7 +455,7 @@ ftcrfont_shape (Lisp_Object lgstring, Lisp_Object direction)
 }
 #endif
 
-#ifdef HAVE_OTF_GET_VARIATION_GLYPHS
+#if defined HAVE_OTF_GET_VARIATION_GLYPHS || defined HAVE_FT_FACE_GETCHARVARIANTINDEX
 static int
 ftcrfont_variation_glyphs (struct font *font, int c, unsigned variations[256])
 {
@@ -470,7 +470,7 @@ ftcrfont_variation_glyphs (struct font *font, int c, unsigned variations[256])
 
   return result;
 }
-#endif  /* HAVE_OTF_GET_VARIATION_GLYPHS */
+#endif  /* HAVE_OTF_GET_VARIATION_GLYPHS || HAVE_FT_FACE_GETCHARVARIANTINDEX */
 
 static int
 ftcrfont_draw (struct glyph_string *s,
@@ -583,7 +583,7 @@ struct font_driver const ftcrfont_driver =
 #if defined HAVE_M17N_FLT && defined HAVE_LIBOTF
   .shape = ftcrfont_shape,
 #endif
-#ifdef HAVE_OTF_GET_VARIATION_GLYPHS
+#if defined HAVE_OTF_GET_VARIATION_GLYPHS || defined HAVE_FT_FACE_GETCHARVARIANTINDEX
   .get_variation_glyphs = ftcrfont_variation_glyphs,
 #endif
   .filter_properties = ftfont_filter_properties,
diff --git a/src/ftfont.c b/src/ftfont.c
index 97ab4d0e377..efd0fcbd8c0 100644
--- a/src/ftfont.c
+++ b/src/ftfont.c
@@ -2820,21 +2820,41 @@ ftfont_shape (Lisp_Object lgstring, Lisp_Object direction)
 
 #endif  /* HAVE_M17N_FLT */
 
-#ifdef HAVE_OTF_GET_VARIATION_GLYPHS
+#endif  /* HAVE_LIBOTF */
 
+#if defined HAVE_OTF_GET_VARIATION_GLYPHS || defined HAVE_FT_FACE_GETCHARVARIANTINDEX
 int
 ftfont_variation_glyphs (struct font *font, int c, unsigned variations[256])
 {
   struct font_info *ftfont_info = (struct font_info *) font;
+#ifdef HAVE_OTF_GET_VARIATION_GLYPHS
   OTF *otf = ftfont_get_otf (ftfont_info);
 
   if (! otf)
     return 0;
   return OTF_get_variation_glyphs (otf, c, variations);
-}
+#else  /* !HAVE_OTF_GET_VARIATION_GLYPHS */
+  FT_Face ft_face = ftfont_info->ft_size->face;
+  int i, n = 0;
 
-#endif  /* HAVE_OTF_GET_VARIATION_GLYPHS */
-#endif  /* HAVE_LIBOTF */
+  for (i = 0; i < 16; i++)
+    {
+      variations[i] = FT_Face_GetCharVariantIndex (ft_face, c, 0xFE00 + i);
+      if (variations[i])
+        n++;
+    }
+  for (; i < 256; i++)
+    {
+      variations[i] = FT_Face_GetCharVariantIndex (ft_face, c,
+                                                   0xE0100 + (i - 16));
+      if (variations[i])
+        n++;
+    }
+
+  return n;
+#endif  /* !HAVE_OTF_GET_VARIATION_GLYPHS */
+}
+#endif /* HAVE_OTF_GET_VARIATION_GLYPHS || HAVE_FT_FACE_GETCHARVARIANTINDEX */
 
 #ifdef HAVE_HARFBUZZ
 
@@ -2936,7 +2956,7 @@ static struct font_driver const ftfont_driver =
 #if defined HAVE_M17N_FLT && defined HAVE_LIBOTF
   .shape = ftfont_shape,
 #endif
-#ifdef HAVE_OTF_GET_VARIATION_GLYPHS
+#if defined HAVE_OTF_GET_VARIATION_GLYPHS || defined HAVE_FT_FACE_GETCHARVARIANTINDEX
   .get_variation_glyphs = ftfont_variation_glyphs,
 #endif
   .filter_properties = ftfont_filter_properties,
diff --git a/src/ftxfont.c b/src/ftxfont.c
index da3e3fbae10..b1467360ad6 100644
--- a/src/ftxfont.c
+++ b/src/ftxfont.c
@@ -351,7 +351,7 @@ struct font_driver const ftxfont_driver =
 #if defined HAVE_M17N_FLT && defined HAVE_LIBOTF
   .shape = ftfont_shape,
 #endif
-#ifdef HAVE_OTF_GET_VARIATION_GLYPHS
+#if defined HAVE_OTF_GET_VARIATION_GLYPHS || defined HAVE_FT_FACE_GETCHARVARIANTINDEX
   .get_variation_glyphs = ftfont_variation_glyphs,
 #endif
   .filter_properties = ftfont_filter_properties,
diff --git a/src/xftfont.c b/src/xftfont.c
index c1b93b76f57..04cda12fb52 100644
--- a/src/xftfont.c
+++ b/src/xftfont.c
@@ -661,7 +661,7 @@ struct font_driver const xftfont_driver =
 #if defined HAVE_M17N_FLT && defined HAVE_LIBOTF
   .shape = xftfont_shape,
 #endif
-#ifdef HAVE_OTF_GET_VARIATION_GLYPHS
+#if defined HAVE_OTF_GET_VARIATION_GLYPHS || defined HAVE_FT_FACE_GETCHARVARIANTINDEX
   .get_variation_glyphs = ftfont_variation_glyphs,
 #endif
   .filter_properties = ftfont_filter_properties,