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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 SkTileGridPicture_DEFINED
9 #define SkTileGridPicture_DEFINED
10 
11 #include "SkPicture.h"
12 #include "SkPoint.h"
13 #include "SkSize.h"
14 
15 /**
16  * Subclass of SkPicture that override the behavior of the
17  * kOptimizeForClippedPlayback_RecordingFlag by creating an SkTileGrid
18  * structure rather than an R-Tree. The tile grid has lower recording
19  * and playback costs, but is less effective at eliminating extraneous
20  * primitives for arbitrary query rectangles. It is most effective for
21  * tiled playback when the tile structure is known at record time.
22  */
23 class SK_API SkTileGridPicture : public SkPicture {
24 public:
25     struct TileGridInfo {
26         /** Tile placement interval */
27         SkISize  fTileInterval;
28 
29         /** Pixel coverage overlap between adjacent tiles */
30         SkISize  fMargin;
31 
32         /** Offset added to device-space bounding box positions to convert
33           * them to tile-grid space. This can be used to adjust the "phase"
34           * of the tile grid to match probable query rectangles that will be
35           * used to search into the tile grid. As long as the offset is smaller
36           * or equal to the margin, there is no need to extend the domain of
37           * the tile grid to prevent data loss.
38           */
39         SkIPoint fOffset;
40     };
41     /**
42      * Constructor
43      * @param width recording canvas width in device pixels
44      * @param height recording canvas height in device pixels
45      * @param info description of the tiling layout
46      */
47     SkTileGridPicture(int width, int height, const TileGridInfo& info);
48 
49     virtual SkBBoxHierarchy* createBBoxHierarchy() const SK_OVERRIDE;
50 
51 private:
52     int fXTileCount, fYTileCount;
53     TileGridInfo fInfo;
54 };
55 
56 #endif
57