Restored binary compatibility for TTF_GetFontKerningSize().

The (corrected) behavior of this function has been moved to a new API, named TTF_GetFontKerningSizeGlyphs(), and the original function has been restored to its wrong behavior and marked as deprecated.
libsdl-org · Jan 29, 2016 · 2b0fd50 · 2b0fd50
1 parent 96a6be4
commit 2b0fd50
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Showing 2 changed files with 23 additions and 2 deletions.
diff --git a/SDL_ttf.c b/SDL_ttf.c
@@ -2196,7 +2196,15 @@ int TTF_WasInit( void )
     return TTF_initialized;
 }
 
-int TTF_GetFontKerningSize(TTF_Font *font, Uint16 previous_ch, Uint16 ch)
+/* don't use this function. It's just here for binary compatibility. */
+int TTF_GetFontKerningSize(TTF_Font* font, int prev_index, int index)
+{
+    FT_Vector delta;
+    FT_Get_Kerning( font->face, prev_index, index, ft_kerning_default, &delta );
+    return (delta.x >> 6);
+}
+
+int TTF_GetFontKerningSizeGlyphs(TTF_Font *font, Uint16 previous_ch, Uint16 ch)
 {
     int error;
     int glyph_index, prev_index;
@@ -2231,3 +2239,4 @@ int TTF_GetFontKerningSize(TTF_Font *font, Uint16 previous_ch, Uint16 ch)
     }
     return (delta.x >> 6);
 }
+
diff --git a/SDL_ttf.h b/SDL_ttf.h
@@ -24,6 +24,10 @@
     http://www.freetype.org/
 */
 
+/* Note: In many places, SDL_ttf will say "glyph" when it means "code point."
+   Unicode is hard, we learn as we go, and we apologize for adding to the
+   confusion. */
+
 #ifndef _SDL_TTF_H
 #define _SDL_TTF_H
 
@@ -247,8 +251,16 @@ extern DECLSPEC void SDLCALL TTF_Quit(void);
 /* Check if the TTF engine is initialized */
 extern DECLSPEC int SDLCALL TTF_WasInit(void);
 
+/* Get the kerning size of two glyphs indices */
+/* DEPRECATED: this function requires FreeType font indexes, not glyphs,
+   by accident, which we don't expose through this API, so it could give
+   wildly incorrect results, especially with non-ASCII values.
+   Going forward, please use TTF_GetFontKerningSizeGlyphs() instead, which
+   does what you probably expected this function to do. */
+extern DECLSPEC int TTF_GetFontKerningSize(TTF_Font *font, int prev_index, int index) SDL_DEPRECATED;
+
 /* Get the kerning size of two glyphs */
-extern DECLSPEC int TTF_GetFontKerningSize(TTF_Font *font, Uint16 previous_ch, Uint16 ch);
+extern DECLSPEC int TTF_GetFontKerningSizeGlyphs(TTF_Font *font, Uint16 previous_ch, Uint16 ch);
 
 /* We'll use SDL for reporting errors */
 #define TTF_SetError    SDL_SetError