prototype for kerning api

src/ports/SkFontHost_FreeType.cpp

 
 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBitmap.h"
 #include "SkCanvas.h"
@@ skipping 711 matching lines @@
     }
 #endif
 }
 
 int SkTypeface_FreeType::onGetUPEM() const {
     AutoFTAccess fta(this);
     FT_Face face = fta.face();
     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) {
     SkAutoMutexAcquire  ac(gFTMutex);
 
     if (gFTCount == 0) {
         if (!InitFreetype()) {
             sk_throw();
         }
     }
@@ skipping 759 matching lines @@
         *style = (SkTypeface::Style) tempStyle;
     }
     if (isFixedPitch) {
         *isFixedPitch = FT_IS_FIXED_WIDTH(face);
     }
 
     FT_Done_Face(face);
     FT_Done_FreeType(library);
     return true;
 }