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/SkDeferredDisplayList.h"
13 #include "include/core/SkSurface.h"
14 #include "src/core/SkImagePriv.h"
15 #include "src/core/SkSurfacePriv.h"
16
17 class SkSurface_Base : public SkSurface {
18 public:
19 SkSurface_Base(int width, int height, const SkSurfaceProps*);
20 SkSurface_Base(const SkImageInfo&, const SkSurfaceProps*);
21 ~SkSurface_Base() override;
22
23 virtual GrRecordingContext* onGetRecordingContext();
24
25 #if SK_SUPPORT_GPU
26 virtual GrBackendTexture onGetBackendTexture(BackendHandleAccess);
27 virtual GrBackendRenderTarget onGetBackendRenderTarget(BackendHandleAccess);
28 virtual bool onReplaceBackendTexture(const GrBackendTexture&,
29 GrSurfaceOrigin,
30 ContentChangeMode,
31 TextureReleaseProc,
32 ReleaseContext);
33
onResolveMSAA()34 virtual void onResolveMSAA() {}
35
36 /**
37 * Issue any pending surface IO to the current backend 3D API and resolve any surface MSAA.
38 * Inserts the requested number of semaphores for the gpu to signal when work is complete on the
39 * gpu and inits the array of GrBackendSemaphores with the signaled semaphores.
40 */
onFlush(BackendSurfaceAccess access,const GrFlushInfo &,const GrBackendSurfaceMutableState *)41 virtual GrSemaphoresSubmitted onFlush(BackendSurfaceAccess access, const GrFlushInfo&,
42 const GrBackendSurfaceMutableState*) {
43 return GrSemaphoresSubmitted::kNo;
44 }
45 #endif
46
47 /**
48 * Allocate a canvas that will draw into this surface. We will cache this
49 * canvas, to return the same object to the caller multiple times. We
50 * take ownership, and will call unref() on the canvas when we go out of
51 * scope.
52 */
53 virtual SkCanvas* onNewCanvas() = 0;
54
55 virtual sk_sp<SkSurface> onNewSurface(const SkImageInfo&) = 0;
56
57 /**
58 * Allocate an SkImage that represents the current contents of the surface.
59 * This needs to be able to outlive the surface itself (if need be), and
60 * must faithfully represent the current contents, even if the surface
61 * is changed after this called (e.g. it is drawn to via its canvas).
62 *
63 * If a subset is specified, the the impl must make a copy, rather than try to wait
64 * on copy-on-write.
65 */
66 virtual sk_sp<SkImage> onNewImageSnapshot(const SkIRect* subset = nullptr) { return nullptr; }
67
68 virtual void onWritePixels(const SkPixmap&, int x, int y) = 0;
69
70 /**
71 * Default implementation does a rescale/read and then calls the callback.
72 */
73 virtual void onAsyncRescaleAndReadPixels(const SkImageInfo&,
74 const SkIRect& srcRect,
75 RescaleGamma,
76 RescaleMode,
77 ReadPixelsCallback,
78 ReadPixelsContext);
79 /**
80 * Default implementation does a rescale/read/yuv conversion and then calls the callback.
81 */
82 virtual void onAsyncRescaleAndReadPixelsYUV420(SkYUVColorSpace,
83 sk_sp<SkColorSpace> dstColorSpace,
84 const SkIRect& srcRect,
85 const SkISize& dstSize,
86 RescaleGamma,
87 RescaleMode,
88 ReadPixelsCallback,
89 ReadPixelsContext);
90
91 /**
92 * Default implementation:
93 *
94 * image = this->newImageSnapshot();
95 * if (image) {
96 * image->draw(canvas, ...);
97 * image->unref();
98 * }
99 */
100 virtual void onDraw(SkCanvas*, SkScalar x, SkScalar y, const SkSamplingOptions&,const SkPaint*);
101
102 /**
103 * Called as a performance hint when the Surface is allowed to make it's contents
104 * undefined.
105 */
onDiscard()106 virtual void onDiscard() {}
107
108 /**
109 * If the surface is about to change, we call this so that our subclass
110 * can optionally fork their backend (copy-on-write) in case it was
111 * being shared with the cachedImage.
112 *
113 * Returns false if the backing cannot be un-shared.
114 */
115 virtual bool SK_WARN_UNUSED_RESULT onCopyOnWrite(ContentChangeMode) = 0;
116
117 /**
118 * Signal the surface to remind its backing store that it's mutable again.
119 * Called only when we _didn't_ copy-on-write; we assume the copies start mutable.
120 */
onRestoreBackingMutability()121 virtual void onRestoreBackingMutability() {}
122
123 /**
124 * Caused the current backend 3D API to wait on the passed in semaphores before executing new
125 * commands on the gpu. Any previously submitting commands will not be blocked by these
126 * semaphores.
127 */
onWait(int numSemaphores,const GrBackendSemaphore * waitSemaphores,bool deleteSemaphoresAfterWait)128 virtual bool onWait(int numSemaphores, const GrBackendSemaphore* waitSemaphores,
129 bool deleteSemaphoresAfterWait) {
130 return false;
131 }
132
onCharacterize(SkSurfaceCharacterization *)133 virtual bool onCharacterize(SkSurfaceCharacterization*) const { return false; }
onIsCompatible(const SkSurfaceCharacterization &)134 virtual bool onIsCompatible(const SkSurfaceCharacterization&) const { return false; }
onDraw(sk_sp<const SkDeferredDisplayList>,SkIPoint offset)135 virtual bool onDraw(sk_sp<const SkDeferredDisplayList>, SkIPoint offset) {
136 return false;
137 }
138
139 inline SkCanvas* getCachedCanvas();
140 inline sk_sp<SkImage> refCachedImage();
141
hasCachedImage()142 bool hasCachedImage() const { return fCachedImage != nullptr; }
143
144 // called by SkSurface to compute a new genID
145 uint32_t newGenerationID();
146
147 private:
148 std::unique_ptr<SkCanvas> fCachedCanvas;
149 sk_sp<SkImage> fCachedImage;
150
151 // Returns false if drawing should not take place (allocation failure).
152 bool SK_WARN_UNUSED_RESULT aboutToDraw(ContentChangeMode mode);
153
154 // Returns true if there is an outstanding image-snapshot, indicating that a call to aboutToDraw
155 // would trigger a copy-on-write.
156 bool outstandingImageSnapshot() const;
157
158 friend class SkCanvas;
159 friend class SkSurface;
160
161 using INHERITED = SkSurface;
162 };
163
getCachedCanvas()164 SkCanvas* SkSurface_Base::getCachedCanvas() {
165 if (nullptr == fCachedCanvas) {
166 fCachedCanvas = std::unique_ptr<SkCanvas>(this->onNewCanvas());
167 if (fCachedCanvas) {
168 fCachedCanvas->setSurfaceBase(this);
169 }
170 }
171 return fCachedCanvas.get();
172 }
173
refCachedImage()174 sk_sp<SkImage> SkSurface_Base::refCachedImage() {
175 if (fCachedImage) {
176 return fCachedImage;
177 }
178
179 fCachedImage = this->onNewImageSnapshot();
180
181 SkASSERT(!fCachedCanvas || fCachedCanvas->getSurfaceBase() == this);
182 return fCachedImage;
183 }
184
185 #endif
186