grab from latest android

git-svn-id: http://skia.googlecode.com/svn/trunk@27 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 62 insertions, 0 deletions

diff --git a/src/core/SkAutoKern.h b/src/core/SkAutoKern.h
new file mode 100644
index 0000000000..023cb6b2fe
--- /dev/null
+++ b/src/core/SkAutoKern.h
@@ -0,0 +1,62 @@
+/* libs/graphics/sgl/SkAutoKern.h
+**
+** Copyright 2006, The Android Open Source Project
+**
+** Licensed under the Apache License, Version 2.0 (the "License"); 
+** you may not use this file except in compliance with the License. 
+** You may obtain a copy of the License at 
+**
+**     http://www.apache.org/licenses/LICENSE-2.0 
+**
+** Unless required by applicable law or agreed to in writing, software 
+** distributed under the License is distributed on an "AS IS" BASIS, 
+** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
+** See the License for the specific language governing permissions and 
+** limitations under the License.
+*/
+
+#ifndef SkAutoKern_DEFINED
+#define SkAutoKern_DEFINED
+
+#include "SkScalerContext.h"
+
+#define SkAutoKern_AdjustF(prev, next)    (((next) - (prev) + 32) >> 6 << 16)
+#define SkAutoKern_AdjustS(prev, next)    SkIntToScalar(((next) - (prev) + 32) >> 6)
+
+/* this is a helper class to perform auto-kerning
+ * the adjust() method returns a SkFixed corresponding
+ * to a +1/0/-1 pixel adjustment
+ */
+
+class SkAutoKern {
+public:
+    SkAutoKern() : fPrevRsbDelta(0) {}
+
+    SkFixed  adjust(const SkGlyph&  glyph) 
+    {
+//        if (SkAbs32(glyph.fLsbDelta) > 47 || SkAbs32(glyph.fRsbDelta) > 47)
+//            printf("------- %d> L %d R %d\n", glyph.f_GlyphID, glyph.fLsbDelta, glyph.fRsbDelta);
+
+#if 0
+        int  distort = fPrevRsbDelta - glyph.fLsbDelta;
+
+        fPrevRsbDelta = glyph.fRsbDelta;
+
+        if (distort >= 32)
+            return -SK_Fixed1;
+        else if (distort < -32)
+            return +SK_Fixed1;
+        else
+            return 0;
+#else
+        SkFixed adjust = SkAutoKern_AdjustF(fPrevRsbDelta, glyph.fLsbDelta);
+        fPrevRsbDelta = glyph.fRsbDelta;
+        return adjust;
+#endif
+    }
+private:
+    int   fPrevRsbDelta;
+};
+
+#endif
+