1/*
2 * Copyright 2009 The Android Open Source Project
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8
9#ifndef SkEdgeClipper_DEFINED
10#define SkEdgeClipper_DEFINED
11
12#include "SkPath.h"
13
14/** This is basically an iterator. It is initialized with an edge and a clip,
15    and then next() is called until it returns kDone_Verb.
16 */
17class SkEdgeClipper {
18public:
19    SkEdgeClipper(bool canCullToTheRight) : fCanCullToTheRight(canCullToTheRight) {}
20
21    bool clipLine(SkPoint p0, SkPoint p1, const SkRect& clip);
22    bool clipQuad(const SkPoint pts[3], const SkRect& clip);
23    bool clipCubic(const SkPoint pts[4], const SkRect& clip);
24
25    SkPath::Verb next(SkPoint pts[]);
26
27    bool canCullToTheRight() const { return fCanCullToTheRight; }
28
29private:
30    SkPoint*        fCurrPoint;
31    SkPath::Verb*   fCurrVerb;
32    const bool      fCanCullToTheRight;
33
34    enum {
35        kMaxVerbs = 18,  // max curvature in X and Y split cubic into 9 pieces, * (line + cubic)
36        kMaxPoints = 54  // 2 lines + 1 cubic require 6 points; times 9 pieces
37    };
38    SkPoint         fPoints[kMaxPoints];
39    SkPath::Verb    fVerbs[kMaxVerbs];
40
41    void clipMonoQuad(const SkPoint srcPts[3], const SkRect& clip);
42    void clipMonoCubic(const SkPoint srcPts[4], const SkRect& clip);
43    void appendLine(SkPoint p0, SkPoint p1);
44    void appendVLine(SkScalar x, SkScalar y0, SkScalar y1, bool reverse);
45    void appendQuad(const SkPoint pts[3], bool reverse);
46    void appendCubic(const SkPoint pts[4], bool reverse);
47};
48
49#ifdef SK_DEBUG
50    void sk_assert_monotonic_x(const SkPoint pts[], int count);
51    void sk_assert_monotonic_y(const SkPoint pts[], int count);
52#else
53    #define sk_assert_monotonic_x(pts, count)
54    #define sk_assert_monotonic_y(pts, count)
55#endif
56
57#endif
58