michael@0: 
michael@0: /*
michael@0:  * Copyright 2006 The Android Open Source Project
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: 
michael@0: 
michael@0: #ifndef SkPerspIter_DEFINED
michael@0: #define SkPerspIter_DEFINED
michael@0: 
michael@0: #include "SkMatrix.h"
michael@0: 
michael@0: class SkPerspIter {
michael@0: public:
michael@0:     /** Iterate a line through the matrix [x,y] ... [x+count-1, y].
michael@0:         @param m    The matrix we will be iterating a line through
michael@0:         @param x    The initial X coordinate to be mapped through the matrix
michael@0:         @param y    The initial Y coordinate to be mapped through the matrix
michael@0:         @param count The number of points (x,y) (x+1,y) (x+2,y) ... we will eventually map
michael@0:     */
michael@0:     SkPerspIter(const SkMatrix& m, SkScalar x, SkScalar y, int count);
michael@0: 
michael@0:     /** Return the buffer of [x,y] fixed point values we will be filling.
michael@0:         This always returns the same value, so it can be saved across calls to
michael@0:         next().
michael@0:     */
michael@0:     const SkFixed* getXY() const { return fStorage; }
michael@0: 
michael@0:     /** Return the number of [x,y] pairs that have been filled in the getXY() buffer.
michael@0:         When this returns 0, the iterator is finished.
michael@0:     */
michael@0:     int next();
michael@0: 
michael@0: private:
michael@0:     enum {
michael@0:         kShift  = 4,
michael@0:         kCount  = (1 << kShift)
michael@0:     };
michael@0:     const SkMatrix& fMatrix;
michael@0:     SkFixed         fStorage[kCount * 2];
michael@0:     SkFixed         fX, fY;
michael@0:     SkScalar        fSX, fSY;
michael@0:     int             fCount;
michael@0: };
michael@0: 
michael@0: #endif