fontselect: expose a fontprovider selection API

Allow the user of libass to select the font provider from ass_set_fonts. This
API change actually doesn't break client code which was passing `fc=1`; now
the same value will autodetect a usable font provider.

Also add an api to list available font providers as that is useful for client
code to show drop down menus with a font provider to choose from.

1 files changed, 19 insertions, 2 deletions

diff --git a/libass/ass.h b/libass/ass.h
index 1f8a506..a3feb0b 100644
--- a/libass/ass.h
+++ b/libass/ass.h
@@ -176,6 +176,23 @@ typedef enum {
 int ass_library_version(void);
 
 /**
+ * \brief Default Font provider to load fonts in libass' database
+ *
+ * NONE don't use any default font provider for font lookup
+ * AUTODETECT use the first available font provider
+ * CORETEXT force a CoreText based font provider (OS X only)
+ * FONTCONFIG force a Fontconfig based font provider
+ *
+ * libass uses the best shaper available by default.
+ */
+typedef enum {
+    ASS_FONTPROVIDER_NONE       = 0,
+    ASS_FONTPROVIDER_AUTODETECT = 1,
+    ASS_FONTPROVIDER_CORETEXT,
+    ASS_FONTPROVIDER_FONTCONFIG,
+} ASS_DefaultFontProvider;
+
+/**
  * \brief Initialize the library.
  * \return library handle or NULL if failed
  */
@@ -397,8 +414,8 @@ void ass_set_line_position(ASS_Renderer *priv, double line_position);
  * NOTE: font lookup must be configured before an ASS_Renderer can be used.
  */
 void ass_set_fonts(ASS_Renderer *priv, const char *default_font,
-                   const char *default_family, int fc, const char *config,
-                   int update);
+                   const char *default_family, ASS_DefaultFontProvider dfp,
+                   const char *config, int update);
 
 /**
  * \brief Set selective style override mode.