1/*
2 * Copyright 2017 Google Inc.
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#ifndef SkRasterClipStack_DEFINED
9#define SkRasterClipStack_DEFINED
10
11#include "include/core/SkClipOp.h"
12#include "src/core/SkRasterClip.h"
13#include "src/core/SkScan.h"
14#include "src/core/SkTBlockList.h"
15
16class SkRasterClipStack : SkNoncopyable {
17public:
18    SkRasterClipStack(int width, int height)
19            : fRootBounds(SkIRect::MakeWH(width, height))
20            , fDisableAA(SkScan::DowngradeClipAA(fRootBounds)) {
21        fStack.emplace_back(SkRasterClip(fRootBounds));
22        SkASSERT(fStack.count() == 1);
23    }
24
25    void setNewSize(int w, int h) {
26        fRootBounds.setXYWH(0, 0, w, h);
27
28        SkASSERT(fStack.count() == 1);
29        Rec& rec = fStack.back();
30        SkASSERT(rec.fDeferredCount == 0);
31        rec.fRC.setRect(fRootBounds);
32    }
33
34    const SkRasterClip& rc() const { return fStack.back().fRC; }
35
36    void save() {
37        SkDEBUGCODE(fCounter += 1);
38        SkASSERT(fStack.back().fDeferredCount >= 0);
39        fStack.back().fDeferredCount += 1;
40    }
41
42    void restore() {
43        SkDEBUGCODE(fCounter -= 1);
44        SkASSERT(fCounter >= 0);
45
46        if (--fStack.back().fDeferredCount < 0) {
47            SkASSERT(fStack.back().fDeferredCount == -1);
48            SkASSERT(fStack.count() > 1);
49            fStack.pop_back();
50        }
51    }
52
53    void clipRect(const SkMatrix& ctm, const SkRect& rect, SkClipOp op, bool aa) {
54        this->writable_rc().op(rect, ctm, op, this->finalAA(aa));
55        this->validate();
56    }
57
58    void clipRRect(const SkMatrix& ctm, const SkRRect& rrect, SkClipOp op, bool aa) {
59        this->writable_rc().op(rrect, ctm, op, this->finalAA(aa));
60        this->validate();
61    }
62
63    void clipPath(const SkMatrix& ctm, const SkPath& path, SkClipOp op, bool aa) {
64        this->writable_rc().op(path, ctm, op, this->finalAA(aa));
65        this->validate();
66    }
67
68    void clipShader(sk_sp<SkShader> sh) {
69        this->writable_rc().op(std::move(sh));
70        this->validate();
71    }
72
73    void clipRegion(const SkRegion& rgn, SkClipOp op) {
74        this->writable_rc().op(rgn, op);
75        this->validate();
76    }
77
78    void replaceClip(const SkIRect& rect) {
79        SkIRect devRect = rect;
80        if (!devRect.intersect(fRootBounds)) {
81            this->writable_rc().setEmpty();
82        } else {
83            this->writable_rc().setRect(devRect);
84        }
85    }
86
87    void validate() const {
88#ifdef SK_DEBUG
89        const SkRasterClip& clip = this->rc();
90        if (fRootBounds.isEmpty()) {
91            SkASSERT(clip.isEmpty());
92        } else if (!clip.isEmpty()) {
93            SkASSERT(fRootBounds.contains(clip.getBounds()));
94        }
95#endif
96    }
97
98private:
99    struct Rec {
100        SkRasterClip fRC;
101        int          fDeferredCount; // 0 for a "normal" entry
102
103        Rec(const SkRasterClip& rc) : fRC(rc), fDeferredCount(0) {}
104    };
105
106    SkTBlockList<Rec, 16> fStack;
107    SkIRect fRootBounds;
108    bool fDisableAA;
109    SkDEBUGCODE(int fCounter = 0);
110
111    SkRasterClip& writable_rc() {
112        SkASSERT(fStack.back().fDeferredCount >= 0);
113        if (fStack.back().fDeferredCount > 0) {
114            fStack.back().fDeferredCount -= 1;
115            fStack.emplace_back(fStack.back().fRC);
116        }
117        return fStack.back().fRC;
118    }
119
120    bool finalAA(bool aa) const { return aa && !fDisableAA; }
121};
122
123#endif
124