prototype for kerning api

src/ports/SkFontHost_FreeType.cpp

Index: src/ports/SkFontHost_FreeType.cpp
diff --git a/src/ports/SkFontHost_FreeType.cpp b/src/ports/SkFontHost_FreeType.cpp
index eb2f28a59dd8567f0fc71e970cc80620ed6830ba..fc14bd36443053772196d8fa5e3c70e22b5f20c6 100644
--- a/src/ports/SkFontHost_FreeType.cpp
+++ b/src/ports/SkFontHost_FreeType.cpp
@@ -729,6 +729,25 @@ int SkTypeface_FreeType::onGetUPEM() const {
     return face ? face->units_per_EM : 0;
 }
 
+bool SkTypeface_FreeType::onGetKerningPairAdjustments(const uint16_t glyphs[],
+                                      int count, int32_t adjustments[]) const {
+    AutoFTAccess fta(this);
+    FT_Face face = fta.face();

[bungeman-skia, 2013/10/29 21:38:41]

I think you want a test around FT_HAS_KERNING(face) here and return false if if
it evaluates to false.

[reed1, 2013/10/30 13:59:37]

Done.

+    
+    for (int i = 0; i < count - 1; ++i) {
+        FT_Vector delta;
+        FT_Error err = FT_Get_Kerning(face, glyphs[i], glyphs[i+1],
+                                      FT_KERNING_UNSCALED, &delta);
+        if (err) {
+            return false;

[bungeman-skia, 2013/10/29 21:38:41]

Hey, the documentation implies that adjustments won't be touched if this returns
false. The documentation should probably be tweaked to say that this will return
false also on failure.

[reed1, 2013/10/30 13:59:37]

Done.

+        }
+        if (adjustments) {
+            adjustments[i] = delta.x;
+        }
+    }
+    return true;
+}
+
 SkScalerContext_FreeType::SkScalerContext_FreeType(SkTypeface* typeface,
                                                    const SkDescriptor* desc)
         : SkScalerContext_FreeType_Base(typeface, desc) {