1 
2 /*
3  * Copyright 2009 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 SkQuadClipper_DEFINED
11 #define SkQuadClipper_DEFINED
12 
13 #include "SkPath.h"
14 
15 /** This class is initialized with a clip rectangle, and then can be fed quads,
16     which must already be monotonic in Y.
17 
18     In the future, it might return a series of segments, allowing it to clip
19     also in X, to ensure that all segments fit in a finite coordinate system.
20  */
21 class SkQuadClipper {
22 public:
23     SkQuadClipper();
24 
25     void setClip(const SkIRect& clip);
26 
27     bool clipQuad(const SkPoint src[3], SkPoint dst[3]);
28 
29 private:
30     SkRect      fClip;
31 };
32 
33 /** Iterator that returns the clipped segements of a quad clipped to a rect.
34     The segments will be either lines or quads (based on SkPath::Verb), and
35     will all be monotonic in Y
36  */
37 class SkQuadClipper2 {
38 public:
39     bool clipQuad(const SkPoint pts[3], const SkRect& clip);
40     bool clipCubic(const SkPoint pts[4], const SkRect& clip);
41 
42     SkPath::Verb next(SkPoint pts[]);
43 
44 private:
45     SkPoint*        fCurrPoint;
46     SkPath::Verb*   fCurrVerb;
47 
48     enum {
49         kMaxVerbs = 13,
50         kMaxPoints = 32
51     };
52     SkPoint         fPoints[kMaxPoints];
53     SkPath::Verb    fVerbs[kMaxVerbs];
54 
55     void clipMonoQuad(const SkPoint srcPts[3], const SkRect& clip);
56     void clipMonoCubic(const SkPoint srcPts[4], const SkRect& clip);
57     void appendVLine(SkScalar x, SkScalar y0, SkScalar y1, bool reverse);
58     void appendQuad(const SkPoint pts[3], bool reverse);
59     void appendCubic(const SkPoint pts[4], bool reverse);
60 };
61 
62 #ifdef SK_DEBUG
63     void sk_assert_monotonic_x(const SkPoint pts[], int count);
64     void sk_assert_monotonic_y(const SkPoint pts[], int count);
65 #else
66     #define sk_assert_monotonic_x(pts, count)
67     #define sk_assert_monotonic_y(pts, count)
68 #endif
69 
70 #endif
71