skia2/include/core/SkPerspIter.h

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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 SkPerspIter_DEFINED
#define SkPerspIter_DEFINED
#include "SkMatrix.h"
class SkPerspIter {
public:
/** Iterate a line through the matrix [x,y] ... [x+count-1, y].
@param m The matrix we will be iterating a line through
@param x The initial X coordinate to be mapped through the matrix
@param y The initial Y coordinate to be mapped through the matrix
@param count The number of points (x,y) (x+1,y) (x+2,y) ... we will eventually map
*/
SkPerspIter(const SkMatrix& m, SkScalar x, SkScalar y, int count);
/** Return the buffer of [x,y] fixed point values we will be filling.
This always returns the same value, so it can be saved across calls to
next().
*/
const SkFixed* getXY() const { return fStorage; }
/** Return the number of [x,y] pairs that have been filled in the getXY() buffer.
When this returns 0, the iterator is finished.
*/
int next();
private:
enum {
kShift = 4,
kCount = (1 << kShift)
};
const SkMatrix& fMatrix;
SkFixed fStorage[kCount * 2];
SkFixed fX, fY;
SkScalar fSX, fSY;
int fCount;
};
#endif