skia2/include/effects/SkAvoidXfermode.h
reed@android.com 0db5a7fae5 update dox for SkAvoidXfermode (as best I could)
fix 565 and 4444 implementations



git-svn-id: http://skia.googlecode.com/svn/trunk@420 2bbb7eff-a529-9590-31e7-b0007b416f81
2009-11-09 16:01:36 +00:00

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2.7 KiB
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/*
* Copyright (C) 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 SkAvoidXfermode_DEFINED
#define SkAvoidXfermode_DEFINED
#include "SkXfermode.h"
/** \class SkAvoidXfermode
This xfermode will draw the src everywhere except on top of the specified
color.
*/
class SkAvoidXfermode : public SkXfermode {
public:
enum Mode {
kAvoidColor_Mode, //!< draw everywhere except on the opColor
kTargetColor_Mode //!< draw only on top of the opColor
};
/** This xfermode draws, or doesn't draw, based on the destination's
distance from an op-color.
There are two modes, and each mode interprets a tolerance value.
Avoid: In this mode, drawing is allowed only on destination pixels that
are different from the op-color.
Tolerance near 0: avoid anything close to the op-color
Tolerance near 255: avoid only colors very close to the op-color
Target: In this mode, drawing only occurs on destination pixels that
are similar to the op-color
Tolerance near 0: draw on colors that are very close to op-color
Tolerance near 255: draw on colors that to the op-color
*/
SkAvoidXfermode(SkColor opColor, U8CPU tolerance, Mode mode);
// overrides from SkXfermode
virtual void xfer32(SkPMColor dst[], const SkPMColor src[], int count,
const SkAlpha aa[]);
virtual void xfer16(uint16_t dst[], const SkPMColor src[], int count,
const SkAlpha aa[]);
virtual void xfer4444(uint16_t dst[], const SkPMColor src[], int count,
const SkAlpha aa[]);
virtual void xferA8(SkAlpha dst[], const SkPMColor src[], int count,
const SkAlpha aa[]);
// overrides from SkFlattenable
virtual Factory getFactory();
virtual void flatten(SkFlattenableWriteBuffer&);
protected:
SkAvoidXfermode(SkFlattenableReadBuffer&);
private:
SkColor fOpColor;
uint32_t fDistMul; // x.14
Mode fMode;
static SkFlattenable* Create(SkFlattenableReadBuffer&);
typedef SkXfermode INHERITED;
};
#endif