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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 GrSWMaskHelper_DEFINED
9 #define GrSWMaskHelper_DEFINED
10 
11 #include "GrTypesPriv.h"
12 #include "SkAutoPixmapStorage.h"
13 #include "SkDraw.h"
14 #include "SkMatrix.h"
15 #include "SkRasterClip.h"
16 #include "SkRegion.h"
17 #include "SkTypes.h"
18 
19 class GrShape;
20 class GrTextureProxy;
21 
22 /**
23  * The GrSWMaskHelper helps generate clip masks using the software rendering
24  * path. It is intended to be used as:
25  *
26  *   GrSWMaskHelper helper(context);
27  *   helper.init(...);
28  *
29  *      draw one or more paths/rects specifying the required boolean ops
30  *
31  *   toTextureProxy();   // to get it from the internal bitmap to the GPU
32  *
33  * The result of this process will be the final mask (on the GPU) in the
34  * upper left hand corner of the texture.
35  */
36 class GrSWMaskHelper : SkNoncopyable {
37 public:
38     GrSWMaskHelper(SkAutoPixmapStorage* pixels = nullptr)
39             : fPixels(pixels ? pixels : &fPixelsStorage) { }
40 
41     // set up the internal state in preparation for draws. Since many masks
42     // may be accumulated in the helper during creation, "resultBounds"
43     // allows the caller to specify the region of interest - to limit the
44     // amount of work.
45     bool init(const SkIRect& resultBounds);
46 
47     // Draw a single rect into the accumulation bitmap using the specified op
48     void drawRect(const SkRect& rect, const SkMatrix& matrix, SkRegion::Op op, GrAA, uint8_t alpha);
49 
50     // Draw a single path into the accumuation bitmap using the specified op
51     void drawShape(const GrShape&, const SkMatrix& matrix, SkRegion::Op op, GrAA, uint8_t alpha);
52 
53     sk_sp<GrTextureProxy> toTextureProxy(GrContext*, SkBackingFit fit);
54 
55     // Reset the internal bitmap
clear(uint8_t alpha)56     void clear(uint8_t alpha) {
57         fPixels->erase(SkColorSetARGB(alpha, 0xFF, 0xFF, 0xFF));
58     }
59 
60 private:
61     SkVector             fTranslate;
62     SkAutoPixmapStorage* fPixels;
63     SkAutoPixmapStorage  fPixelsStorage;
64     SkDraw               fDraw;
65     SkRasterClip         fRasterClip;
66 
67     typedef SkNoncopyable INHERITED;
68 };
69 
70 #endif // GrSWMaskHelper_DEFINED
71