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