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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 #include "include/core/SkCanvas.h"
9 #include "include/core/SkMallocPixelRef.h"
10 #include "include/private/SkImageInfoPriv.h"
11 #include "src/core/SkDevice.h"
12 #include "src/core/SkImagePriv.h"
13 #include "src/image/SkSurface_Base.h"
14 
15 class SkSurface_Raster : public SkSurface_Base {
16 public:
17     SkSurface_Raster(const SkImageInfo&, void*, size_t rb,
18                      void (*releaseProc)(void* pixels, void* context), void* context,
19                      const SkSurfaceProps*);
20     SkSurface_Raster(const SkImageInfo& info, sk_sp<SkPixelRef>, const SkSurfaceProps*);
21 
22     SkCanvas* onNewCanvas() override;
23     sk_sp<SkSurface> onNewSurface(const SkImageInfo&) override;
24     sk_sp<SkImage> onNewImageSnapshot(const SkIRect* subset) override;
25     void onWritePixels(const SkPixmap&, int x, int y) override;
26     void onDraw(SkCanvas*, SkScalar x, SkScalar y, const SkPaint*) override;
27     void onCopyOnWrite(ContentChangeMode) override;
28     void onRestoreBackingMutability() override;
29 
30 private:
31     SkBitmap    fBitmap;
32     size_t      fRowBytes;
33     bool        fWeOwnThePixels;
34 
35     typedef SkSurface_Base INHERITED;
36 };
37 
38 ///////////////////////////////////////////////////////////////////////////////
39 
SkSurfaceValidateRasterInfo(const SkImageInfo & info,size_t rowBytes)40 bool SkSurfaceValidateRasterInfo(const SkImageInfo& info, size_t rowBytes) {
41     if (!SkImageInfoIsValid(info)) {
42         return false;
43     }
44 
45     if (kIgnoreRowBytesValue == rowBytes) {
46         return true;
47     }
48 
49     int shift = info.shiftPerPixel();
50 
51     uint64_t minRB = (uint64_t)info.width() << shift;
52     if (minRB > rowBytes) {
53         return false;
54     }
55 
56     size_t alignedRowBytes = rowBytes >> shift << shift;
57     if (alignedRowBytes != rowBytes) {
58         return false;
59     }
60 
61     uint64_t size = sk_64_mul(info.height(), rowBytes);
62     static const size_t kMaxTotalSize = SK_MaxS32;
63     if (size > kMaxTotalSize) {
64         return false;
65     }
66 
67     return true;
68 }
69 
SkSurface_Raster(const SkImageInfo & info,void * pixels,size_t rb,void (* releaseProc)(void * pixels,void * context),void * context,const SkSurfaceProps * props)70 SkSurface_Raster::SkSurface_Raster(const SkImageInfo& info, void* pixels, size_t rb,
71                                    void (*releaseProc)(void* pixels, void* context), void* context,
72                                    const SkSurfaceProps* props)
73     : INHERITED(info, props)
74 {
75     fBitmap.installPixels(info, pixels, rb, releaseProc, context);
76     fRowBytes = 0;              // don't need to track the rowbytes
77     fWeOwnThePixels = false;    // We are "Direct"
78 }
79 
SkSurface_Raster(const SkImageInfo & info,sk_sp<SkPixelRef> pr,const SkSurfaceProps * props)80 SkSurface_Raster::SkSurface_Raster(const SkImageInfo& info, sk_sp<SkPixelRef> pr,
81                                    const SkSurfaceProps* props)
82     : INHERITED(pr->width(), pr->height(), props)
83 {
84     fBitmap.setInfo(info, pr->rowBytes());
85     fRowBytes = pr->rowBytes(); // we track this, so that subsequent re-allocs will match
86     fBitmap.setPixelRef(std::move(pr), 0, 0);
87     fWeOwnThePixels = true;
88 }
89 
onNewCanvas()90 SkCanvas* SkSurface_Raster::onNewCanvas() { return new SkCanvas(fBitmap, this->props()); }
91 
onNewSurface(const SkImageInfo & info)92 sk_sp<SkSurface> SkSurface_Raster::onNewSurface(const SkImageInfo& info) {
93     return SkSurface::MakeRaster(info, &this->props());
94 }
95 
onDraw(SkCanvas * canvas,SkScalar x,SkScalar y,const SkPaint * paint)96 void SkSurface_Raster::onDraw(SkCanvas* canvas, SkScalar x, SkScalar y,
97                               const SkPaint* paint) {
98     canvas->drawBitmap(fBitmap, x, y, paint);
99 }
100 
onNewImageSnapshot(const SkIRect * subset)101 sk_sp<SkImage> SkSurface_Raster::onNewImageSnapshot(const SkIRect* subset) {
102     if (subset) {
103         SkASSERT(SkIRect::MakeWH(fBitmap.width(), fBitmap.height()).contains(*subset));
104         SkBitmap dst;
105         dst.allocPixels(fBitmap.info().makeWH(subset->width(), subset->height()));
106         SkAssertResult(fBitmap.readPixels(dst.pixmap(), subset->left(), subset->top()));
107         dst.setImmutable(); // key, so MakeFromBitmap doesn't make a copy of the buffer
108         return SkImage::MakeFromBitmap(dst);
109     }
110 
111     SkCopyPixelsMode cpm = kIfMutable_SkCopyPixelsMode;
112     if (fWeOwnThePixels) {
113         // SkImage_raster requires these pixels are immutable for its full lifetime.
114         // We'll undo this via onRestoreBackingMutability() if we can avoid the COW.
115         if (SkPixelRef* pr = fBitmap.pixelRef()) {
116             pr->setTemporarilyImmutable();
117         }
118     } else {
119         cpm = kAlways_SkCopyPixelsMode;
120     }
121 
122     // Our pixels are in memory, so read access on the snapshot SkImage could be cheap.
123     // Lock the shared pixel ref to ensure peekPixels() is usable.
124     return SkMakeImageFromRasterBitmap(fBitmap, cpm);
125 }
126 
onWritePixels(const SkPixmap & src,int x,int y)127 void SkSurface_Raster::onWritePixels(const SkPixmap& src, int x, int y) {
128     fBitmap.writePixels(src, x, y);
129 }
130 
onRestoreBackingMutability()131 void SkSurface_Raster::onRestoreBackingMutability() {
132     SkASSERT(!this->hasCachedImage());  // Shouldn't be any snapshots out there.
133     if (SkPixelRef* pr = fBitmap.pixelRef()) {
134         pr->restoreMutability();
135     }
136 }
137 
onCopyOnWrite(ContentChangeMode mode)138 void SkSurface_Raster::onCopyOnWrite(ContentChangeMode mode) {
139     // are we sharing pixelrefs with the image?
140     sk_sp<SkImage> cached(this->refCachedImage());
141     SkASSERT(cached);
142     if (SkBitmapImageGetPixelRef(cached.get()) == fBitmap.pixelRef()) {
143         SkASSERT(fWeOwnThePixels);
144         if (kDiscard_ContentChangeMode == mode) {
145             fBitmap.allocPixels();
146         } else {
147             SkBitmap prev(fBitmap);
148             fBitmap.allocPixels();
149             SkASSERT(prev.info() == fBitmap.info());
150             SkASSERT(prev.rowBytes() == fBitmap.rowBytes());
151             memcpy(fBitmap.getPixels(), prev.getPixels(), fBitmap.computeByteSize());
152         }
153         SkASSERT(fBitmap.rowBytes() == fRowBytes);  // be sure we always use the same value
154 
155         // Now fBitmap is a deep copy of itself (and therefore different from
156         // what is being used by the image. Next we update the canvas to use
157         // this as its backend, so we can't modify the image's pixels anymore.
158         SkASSERT(this->getCachedCanvas());
159         this->getCachedCanvas()->getDevice()->replaceBitmapBackendForRasterSurface(fBitmap);
160     }
161 }
162 
163 ///////////////////////////////////////////////////////////////////////////////
164 
MakeRasterDirectReleaseProc(const SkImageInfo & info,void * pixels,size_t rb,void (* releaseProc)(void * pixels,void * context),void * context,const SkSurfaceProps * props)165 sk_sp<SkSurface> SkSurface::MakeRasterDirectReleaseProc(const SkImageInfo& info, void* pixels,
166         size_t rb, void (*releaseProc)(void* pixels, void* context), void* context,
167         const SkSurfaceProps* props) {
168     if (nullptr == releaseProc) {
169         context = nullptr;
170     }
171     if (!SkSurfaceValidateRasterInfo(info, rb)) {
172         return nullptr;
173     }
174     if (nullptr == pixels) {
175         return nullptr;
176     }
177 
178     return sk_make_sp<SkSurface_Raster>(info, pixels, rb, releaseProc, context, props);
179 }
180 
MakeRasterDirect(const SkImageInfo & info,void * pixels,size_t rowBytes,const SkSurfaceProps * props)181 sk_sp<SkSurface> SkSurface::MakeRasterDirect(const SkImageInfo& info, void* pixels, size_t rowBytes,
182                                              const SkSurfaceProps* props) {
183     return MakeRasterDirectReleaseProc(info, pixels, rowBytes, nullptr, nullptr, props);
184 }
185 
MakeRaster(const SkImageInfo & info,size_t rowBytes,const SkSurfaceProps * props)186 sk_sp<SkSurface> SkSurface::MakeRaster(const SkImageInfo& info, size_t rowBytes,
187                                        const SkSurfaceProps* props) {
188     if (!SkSurfaceValidateRasterInfo(info)) {
189         return nullptr;
190     }
191 
192     sk_sp<SkPixelRef> pr = SkMallocPixelRef::MakeAllocate(info, rowBytes);
193     if (!pr) {
194         return nullptr;
195     }
196     if (rowBytes) {
197         SkASSERT(pr->rowBytes() == rowBytes);
198     }
199     return sk_make_sp<SkSurface_Raster>(info, std::move(pr), props);
200 }
201 
MakeRasterN32Premul(int width,int height,const SkSurfaceProps * surfaceProps)202 sk_sp<SkSurface> SkSurface::MakeRasterN32Premul(int width, int height,
203                                                 const SkSurfaceProps* surfaceProps) {
204     return MakeRaster(SkImageInfo::MakeN32Premul(width, height), surfaceProps);
205 }
206