SkAAClip.h revision 202ab2a5cabaf25a1e6ec47c0003da3213a79864 
1
2/*
3 * Copyright 2011 Google Inc.
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#ifndef SkAAClip_DEFINED
10#define SkAAClip_DEFINED
11
12#include "SkBlitter.h"
13#include "SkRegion.h"
14
15class SkAAClip {
16public:
17    SkAAClip();
18    SkAAClip(const SkAAClip&);
19    ~SkAAClip();
20
21    SkAAClip& operator=(const SkAAClip&);
22    friend bool operator==(const SkAAClip&, const SkAAClip&);
23    friend bool operator!=(const SkAAClip& a, const SkAAClip& b) {
24        return !(a == b);
25    }
26
27    void swap(SkAAClip&);
28
29    bool isEmpty() const { return NULL == fRunHead; }
30    const SkIRect& getBounds() const { return fBounds; }
31
32    // Returns true iff the clip is not empty, and is just a hard-edged rect (no partial alpha).
33    // If true, getBounds() can be used in place of this clip.
34    bool isRect() const;
35
36    bool setEmpty();
37    bool setRect(const SkIRect&);
38    bool setRect(const SkRect&, bool doAA = true);
39    bool setPath(const SkPath&, const SkRegion* clip = NULL, bool doAA = true);
40    bool setRegion(const SkRegion&);
41    bool set(const SkAAClip&);
42
43    bool op(const SkAAClip&, const SkAAClip&, SkRegion::Op);
44
45    // Helpers for op()
46    bool op(const SkIRect&, SkRegion::Op);
47    bool op(const SkRect&, SkRegion::Op, bool doAA);
48    bool op(const SkAAClip&, SkRegion::Op);
49
50    bool translate(int dx, int dy, SkAAClip* dst) const;
51    bool translate(int dx, int dy) {
52        return this->translate(dx, dy, this);
53    }
54
55    /**
56     *  Allocates a mask the size of the aaclip, and expands its data into
57     *  the mask, using kA8_Format
58     */
59    void copyToMask(SkMask*) const;
60
61    // called internally
62
63    bool quickContains(int left, int top, int right, int bottom) const;
64    bool quickContains(const SkIRect& r) const {
65        return this->quickContains(r.fLeft, r.fTop, r.fRight, r.fBottom);
66    }
67
68    const uint8_t* findRow(int y, int* lastYForRow = NULL) const;
69    const uint8_t* findX(const uint8_t data[], int x, int* initialCount = NULL) const;
70
71    class Iter;
72    struct RunHead;
73    struct YOffset;
74    class Builder;
75
76#ifdef SK_DEBUG
77    void validate() const;
78#else
79    void validate() const {}
80#endif
81
82private:
83    SkIRect  fBounds;
84    RunHead* fRunHead;
85
86    void freeRuns();
87    bool trimBounds();
88    bool trimTopBottom();
89    bool trimLeftRight();
90
91    friend class Builder;
92    class BuilderBlitter;
93    friend class BuilderBlitter;
94};
95
96///////////////////////////////////////////////////////////////////////////////
97
98class SkAAClipBlitter : public SkBlitter {
99public:
100    SkAAClipBlitter() : fScanlineScratch(NULL) {}
101    virtual ~SkAAClipBlitter();
102
103    void init(SkBlitter* blitter, const SkAAClip* aaclip) {
104        SkASSERT(aaclip && !aaclip->isEmpty());
105        fBlitter = blitter;
106        fAAClip = aaclip;
107        fAAClipBounds = aaclip->getBounds();
108    }
109
110    virtual void blitH(int x, int y, int width) SK_OVERRIDE;
111    virtual void blitAntiH(int x, int y, const SkAlpha[],
112                           const int16_t runs[]) SK_OVERRIDE;
113    virtual void blitV(int x, int y, int height, SkAlpha alpha) SK_OVERRIDE;
114    virtual void blitRect(int x, int y, int width, int height) SK_OVERRIDE;
115    virtual void blitMask(const SkMask&, const SkIRect& clip) SK_OVERRIDE;
116    virtual const SkBitmap* justAnOpaqueColor(uint32_t* value) SK_OVERRIDE;
117
118private:
119    SkBlitter*      fBlitter;
120    const SkAAClip* fAAClip;
121    SkIRect         fAAClipBounds;
122
123    // point into fScanlineScratch
124    int16_t*        fRuns;
125    SkAlpha*        fAA;
126
127    enum {
128        kSize = 32 * 32
129    };
130    SkAutoSMalloc<kSize> fGrayMaskScratch;  // used for blitMask
131    void* fScanlineScratch;  // enough for a mask at 32bit, or runs+aa
132
133    void ensureRunsAndAA();
134};
135
136#endif
137