skia2/include/core/SkAutoKern.h

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/* 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