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 SkSurface_Base_DEFINED
9 #define SkSurface_Base_DEFINED
10
11 #include "include/core/SkCanvas.h"
12 #include "include/core/SkSurface.h"
13 #include "src/core/SkImagePriv.h"
14 #include "src/core/SkSurfacePriv.h"
15
16 class SkSurface_Base : public SkSurface {
17 public:
18 SkSurface_Base(int width, int height, const SkSurfaceProps*);
19 SkSurface_Base(const SkImageInfo&, const SkSurfaceProps*);
20 virtual ~SkSurface_Base();
21
22 virtual GrBackendTexture onGetBackendTexture(BackendHandleAccess);
23 virtual GrBackendRenderTarget onGetBackendRenderTarget(BackendHandleAccess);
24 virtual bool onReplaceBackendTexture(const GrBackendTexture&,
25 GrSurfaceOrigin,
26 ContentChangeMode,
27 TextureReleaseProc,
28 ReleaseContext);
29 /**
30 * Allocate a canvas that will draw into this surface. We will cache this
31 * canvas, to return the same object to the caller multiple times. We
32 * take ownership, and will call unref() on the canvas when we go out of
33 * scope.
34 */
35 virtual SkCanvas* onNewCanvas() = 0;
36
37 virtual sk_sp<SkSurface> onNewSurface(const SkImageInfo&) = 0;
38
39 /**
40 * Allocate an SkImage that represents the current contents of the surface.
41 * This needs to be able to outlive the surface itself (if need be), and
42 * must faithfully represent the current contents, even if the surface
43 * is changed after this called (e.g. it is drawn to via its canvas).
44 *
45 * If a subset is specified, the the impl must make a copy, rather than try to wait
46 * on copy-on-write.
47 */
48 virtual sk_sp<SkImage> onNewImageSnapshot(const SkIRect* subset = nullptr) { return nullptr; }
49
50 virtual void onWritePixels(const SkPixmap&, int x, int y) = 0;
51
52 /**
53 * Default implementation does a rescale/read and then calls the callback.
54 */
55 virtual void onAsyncRescaleAndReadPixels(const SkImageInfo&,
56 const SkIRect& srcRect,
57 RescaleGamma,
58 SkFilterQuality,
59 ReadPixelsCallback,
60 ReadPixelsContext);
61 /**
62 * Default implementation does a rescale/read/yuv conversion and then calls the callback.
63 */
64 virtual void onAsyncRescaleAndReadPixelsYUV420(SkYUVColorSpace,
65 sk_sp<SkColorSpace> dstColorSpace,
66 const SkIRect& srcRect,
67 const SkISize& dstSize,
68 RescaleGamma,
69 SkFilterQuality,
70 ReadPixelsCallback,
71 ReadPixelsContext);
72
73 /**
74 * Default implementation:
75 *
76 * image = this->newImageSnapshot();
77 * if (image) {
78 * image->draw(canvas, ...);
79 * image->unref();
80 * }
81 */
82 virtual void onDraw(SkCanvas*, SkScalar x, SkScalar y, const SkPaint*);
83
84 /**
85 * Called as a performance hint when the Surface is allowed to make it's contents
86 * undefined.
87 */
onDiscard()88 virtual void onDiscard() {}
89
90 /**
91 * If the surface is about to change, we call this so that our subclass
92 * can optionally fork their backend (copy-on-write) in case it was
93 * being shared with the cachedImage.
94 */
95 virtual void onCopyOnWrite(ContentChangeMode) = 0;
96
97 /**
98 * Signal the surface to remind its backing store that it's mutable again.
99 * Called only when we _didn't_ copy-on-write; we assume the copies start mutable.
100 */
onRestoreBackingMutability()101 virtual void onRestoreBackingMutability() {}
102
103 /**
104 * Issue any pending surface IO to the current backend 3D API and resolve any surface MSAA.
105 * Inserts the requested number of semaphores for the gpu to signal when work is complete on the
106 * gpu and inits the array of GrBackendSemaphores with the signaled semaphores.
107 */
onFlush(BackendSurfaceAccess access,const GrFlushInfo &)108 virtual GrSemaphoresSubmitted onFlush(BackendSurfaceAccess access, const GrFlushInfo&) {
109 return GrSemaphoresSubmitted::kNo;
110 }
111
112 /**
113 * Caused the current backend 3D API to wait on the passed in semaphores before executing new
114 * commands on the gpu. Any previously submitting commands will not be blocked by these
115 * semaphores.
116 */
onWait(int numSemaphores,const GrBackendSemaphore * waitSemaphores)117 virtual bool onWait(int numSemaphores, const GrBackendSemaphore* waitSemaphores) {
118 return false;
119 }
120
onCharacterize(SkSurfaceCharacterization *)121 virtual bool onCharacterize(SkSurfaceCharacterization*) const { return false; }
onIsCompatible(const SkSurfaceCharacterization &)122 virtual bool onIsCompatible(const SkSurfaceCharacterization&) const { return false; }
onDraw(const SkDeferredDisplayList *)123 virtual bool onDraw(const SkDeferredDisplayList*) { return false; }
124
125 inline SkCanvas* getCachedCanvas();
126 inline sk_sp<SkImage> refCachedImage();
127
hasCachedImage()128 bool hasCachedImage() const { return fCachedImage != nullptr; }
129
130 // called by SkSurface to compute a new genID
131 uint32_t newGenerationID();
132
133 private:
134 std::unique_ptr<SkCanvas> fCachedCanvas;
135 sk_sp<SkImage> fCachedImage;
136
137 void aboutToDraw(ContentChangeMode mode);
138
139 // Returns true if there is an outstanding image-snapshot, indicating that a call to aboutToDraw
140 // would trigger a copy-on-write.
141 bool outstandingImageSnapshot() const;
142
143 friend class SkCanvas;
144 friend class SkSurface;
145
146 typedef SkSurface INHERITED;
147 };
148
getCachedCanvas()149 SkCanvas* SkSurface_Base::getCachedCanvas() {
150 if (nullptr == fCachedCanvas) {
151 fCachedCanvas = std::unique_ptr<SkCanvas>(this->onNewCanvas());
152 if (fCachedCanvas) {
153 fCachedCanvas->setSurfaceBase(this);
154 }
155 }
156 return fCachedCanvas.get();
157 }
158
refCachedImage()159 sk_sp<SkImage> SkSurface_Base::refCachedImage() {
160 if (fCachedImage) {
161 return fCachedImage;
162 }
163
164 fCachedImage = this->onNewImageSnapshot();
165
166 SkASSERT(!fCachedCanvas || fCachedCanvas->getSurfaceBase() == this);
167 return fCachedImage;
168 }
169
170 #endif
171