1 
2 /*
3  * Copyright 2006 The Android Open Source Project
4  *
5  * Use of this source code is governed by a BSD-style license that can be
6  * found in the LICENSE file.
7  */
8 
9 
10 #ifndef SkPerspIter_DEFINED
11 #define SkPerspIter_DEFINED
12 
13 #include "SkMatrix.h"
14 
15 class SkPerspIter {
16 public:
17     /** Iterate a line through the matrix [x,y] ... [x+count-1, y].
18         @param m    The matrix we will be iterating a line through
19         @param x    The initial X coordinate to be mapped through the matrix
20         @param y    The initial Y coordinate to be mapped through the matrix
21         @param count The number of points (x,y) (x+1,y) (x+2,y) ... we will eventually map
22     */
23     SkPerspIter(const SkMatrix& m, SkScalar x, SkScalar y, int count);
24 
25     /** Return the buffer of [x,y] fixed point values we will be filling.
26         This always returns the same value, so it can be saved across calls to
27         next().
28     */
getXY()29     const SkFixed* getXY() const { return fStorage; }
30 
31     /** Return the number of [x,y] pairs that have been filled in the getXY() buffer.
32         When this returns 0, the iterator is finished.
33     */
34     int next();
35 
36 private:
37     enum {
38         kShift  = 4,
39         kCount  = (1 << kShift)
40     };
41     const SkMatrix& fMatrix;
42     SkFixed         fStorage[kCount * 2];
43     SkFixed         fX, fY;
44     SkScalar        fSX, fSY;
45     int             fCount;
46 };
47 
48 #endif
49