1
2/*
3 * Copyright 2006 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 SkBounder_DEFINED
11#define SkBounder_DEFINED
12
13#include "SkTypes.h"
14#include "SkRefCnt.h"
15#include "SkPoint.h"
16
17struct SkGlyph;
18struct SkIRect;
19struct SkPoint;
20struct SkRect;
21class SkPaint;
22class SkPath;
23class SkRegion;
24
25/** \class SkBounder
26
27    Base class for intercepting the device bounds of shapes before they are drawn.
28    Install a subclass of this in your canvas.
29*/
30class SkBounder : public SkRefCnt {
31public:
32    SK_DECLARE_INST_COUNT(SkBounder)
33
34    SkBounder();
35
36    /* Call to perform a clip test before calling onIRect.
37       Returns the result from onIRect.
38    */
39    bool doIRect(const SkIRect&);
40    bool doIRectGlyph(const SkIRect& , int x, int y, const SkGlyph&);
41
42protected:
43    /** Override in your subclass. This is called with the device bounds of an
44        object (text, geometry, image) just before it is drawn. If your method
45        returns false, the drawing for that shape is aborted. If your method
46        returns true, drawing continues. The bounds your method receives have already
47        been transformed in to device coordinates, and clipped to the current clip.
48    */
49    virtual bool onIRect(const SkIRect&) {
50        return false;
51    }
52
53    /** Passed to onIRectGlyph with the information about the current glyph.
54        LSB and RSB are fixed-point (16.16) coordinates of the start and end
55        of the glyph's advance
56     */
57    struct GlyphRec {
58        SkIPoint    fLSB;   //!< fixed-point left-side-bearing of the glyph
59        SkIPoint    fRSB;   //!< fixed-point right-side-bearing of the glyph
60        uint16_t    fGlyphID;
61        uint16_t    fFlags; //!< currently set to 0
62    };
63
64    /** Optionally, override in your subclass to receive the glyph ID when
65        text drawing supplies the device bounds of the object.
66    */
67    virtual bool onIRectGlyph(const SkIRect& r, const GlyphRec&) {
68        return onIRect(r);
69    }
70
71    /** Called after each shape has been drawn. The default implementation does
72        nothing, but your override could use this notification to signal itself
73        that the offscreen being rendered into needs to be updated to the screen.
74    */
75    virtual void commit();
76
77private:
78    bool doHairline(const SkPoint&, const SkPoint&, const SkPaint&);
79    bool doRect(const SkRect&, const SkPaint&);
80    bool doPath(const SkPath&, const SkPaint&, bool doFill);
81    void setClip(const SkRegion* clip) { fClip = clip; }
82
83    const SkRegion* fClip;
84    friend class SkAutoBounderCommit;
85    friend class SkDraw;
86    friend class SkDrawIter;
87    friend struct Draw1Glyph;
88    friend class SkMaskFilter;
89
90    typedef SkRefCnt INHERITED;
91};
92
93#endif
94