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 "include/core/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
29 /**
30 * Clips each segment from the path, and passes the result (in a clipper) to the
31 * consume proc.
32 */
33 static void ClipPath(const SkPath& path, const SkRect& clip, bool canCullToTheRight,
34 void (*consume)(SkEdgeClipper*, bool newCtr, void* ctx), void* ctx);
35
36private:
37 SkPoint* fCurrPoint;
38 SkPath::Verb* fCurrVerb;
39 const bool fCanCullToTheRight;
40
41 enum {
42 kMaxVerbs = 18, // max curvature in X and Y split cubic into 9 pieces, * (line + cubic)
43 kMaxPoints = 54 // 2 lines + 1 cubic require 6 points; times 9 pieces
44 };
45 SkPoint fPoints[kMaxPoints];
46 SkPath::Verb fVerbs[kMaxVerbs];
47
48 void clipMonoQuad(const SkPoint srcPts[3], const SkRect& clip);
49 void clipMonoCubic(const SkPoint srcPts[4], const SkRect& clip);
50 void appendLine(SkPoint p0, SkPoint p1);
51 void appendVLine(SkScalar x, SkScalar y0, SkScalar y1, bool reverse);
52 void appendQuad(const SkPoint pts[3], bool reverse);
53 void appendCubic(const SkPoint pts[4], bool reverse);
54};
55
56#ifdef SK_DEBUG
57 void sk_assert_monotonic_x(const SkPoint pts[], int count);
58 void sk_assert_monotonic_y(const SkPoint pts[], int count);
59#else
60 #define sk_assert_monotonic_x(pts, count)
61 #define sk_assert_monotonic_y(pts, count)
62#endif
63
64#endif
65