1/*
2 * Copyright 2012 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 SkPictureUtils_DEFINED
9#define SkPictureUtils_DEFINED
10
11#include "SkPicture.h"
12#include "SkTDArray.h"
13
14class SkData;
15struct SkRect;
16
17class SK_API SkPictureUtils {
18public:
19    /**
20     *  Given a rectangular visible "window" into the picture, return an array
21     *  of SkPixelRefs that might intersect that area. To keep the call fast,
22     *  the returned list is not guaranteed to be exact, so it may miss some,
23     *  and it may return false positives.
24     *
25     *  The pixelrefs returned in the SkData are already owned by the picture,
26     *  so the returned pointers are only valid while the picture is in scope
27     *  and remains unchanged.
28     */
29    static SkData* GatherPixelRefs(SkPicture* pict, const SkRect& area);
30
31    /**
32     * SkPixelRefContainer provides a base class for more elaborate pixel ref
33     * query structures (e.g., rtrees, quad-trees, etc.)
34     */
35    class SkPixelRefContainer : public SkRefCnt {
36    public:
37        virtual void add(SkPixelRef* pr, const SkRect& rect) = 0;
38
39        // The returned array may contain duplicates
40        virtual void query(const SkRect& queryRect, SkTDArray<SkPixelRef*> *result) = 0;
41
42    private:
43        typedef SkRefCnt INHERITED;
44    };
45
46    // Simple query structure that just stores a linked list of pixel refs
47    // and rects.
48    class SkPixelRefsAndRectsList : public SkPixelRefContainer {
49    public:
50        virtual void add(SkPixelRef* pr, const SkRect& rect) SK_OVERRIDE {
51            PixelRefAndRect *dst = fArray.append();
52
53            dst->fPixelRef = pr;
54            dst->fRect = rect;
55        }
56
57        virtual void query(const SkRect& queryRect, SkTDArray<SkPixelRef*> *result) SK_OVERRIDE {
58            for (int i = 0; i < fArray.count(); ++i) {
59                if (SkRect::Intersects(fArray[i].fRect, queryRect)) {
60                    *result->append() = fArray[i].fPixelRef;
61                }
62            }
63        }
64
65    private:
66        struct PixelRefAndRect {
67            SkPixelRef* fPixelRef;
68            SkRect      fRect;
69        };
70
71        SkTDArray<PixelRefAndRect> fArray;
72
73        typedef SkPixelRefContainer INHERITED;
74    };
75
76    /**
77     *  Fill the provided pixel ref container with the picture's pixel ref
78     *  and rect information.
79     */
80    static void GatherPixelRefsAndRects(SkPicture* pict, SkPixelRefContainer* prCont);
81};
82
83#endif
84