SkSurface_Raster.cpp revision b64bcbdc3a5aa7b9e3ff216e4617ddc1db9260b5 
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 "SkSurface_Base.h"
9#include "SkImagePriv.h"
10#include "SkCanvas.h"
11#include "SkDevice.h"
12#include "SkMallocPixelRef.h"
13
14static const size_t kIgnoreRowBytesValue = (size_t)~0;
15
16class SkSurface_Raster : public SkSurface_Base {
17public:
18    static bool Valid(const SkImageInfo&, size_t rb = kIgnoreRowBytesValue);
19
20    SkSurface_Raster(const SkImageInfo&, void*, size_t rb,
21                     void (*releaseProc)(void* pixels, void* context), void* context,
22                     const SkSurfaceProps*);
23    SkSurface_Raster(sk_sp<SkPixelRef>, const SkSurfaceProps*);
24
25    SkCanvas* onNewCanvas() override;
26    sk_sp<SkSurface> onNewSurface(const SkImageInfo&) override;
27    sk_sp<SkImage> onNewImageSnapshot() override;
28    void onDraw(SkCanvas*, SkScalar x, SkScalar y, const SkPaint*) override;
29    void onCopyOnWrite(ContentChangeMode) override;
30    void onRestoreBackingMutability() override;
31
32private:
33    SkBitmap    fBitmap;
34    size_t      fRowBytes;
35    bool        fWeOwnThePixels;
36
37    typedef SkSurface_Base INHERITED;
38};
39
40///////////////////////////////////////////////////////////////////////////////
41
42bool SkSurface_Raster::Valid(const SkImageInfo& info, size_t rowBytes) {
43    if (info.isEmpty()) {
44        return false;
45    }
46
47    static const size_t kMaxTotalSize = SK_MaxS32;
48
49    int shift = 0;
50    switch (info.colorType()) {
51        case kAlpha_8_SkColorType:
52            if (info.colorSpace()) {
53                return false;
54            }
55            shift = 0;
56            break;
57        case kRGB_565_SkColorType:
58            if (info.colorSpace()) {
59                return false;
60            }
61            shift = 1;
62            break;
63        case kN32_SkColorType:
64            if (info.colorSpace() && !info.colorSpace()->gammaCloseToSRGB()) {
65                return false;
66            }
67            shift = 2;
68            break;
69        case kRGBA_F16_SkColorType:
70            if (info.colorSpace() && !info.colorSpace()->gammaIsLinear()) {
71                return false;
72            }
73            shift = 3;
74            break;
75        default:
76            return false;
77    }
78
79    if (kIgnoreRowBytesValue == rowBytes) {
80        return true;
81    }
82
83    uint64_t minRB = (uint64_t)info.width() << shift;
84    if (minRB > rowBytes) {
85        return false;
86    }
87
88    size_t alignedRowBytes = rowBytes >> shift << shift;
89    if (alignedRowBytes != rowBytes) {
90        return false;
91    }
92
93    uint64_t size = sk_64_mul(info.height(), rowBytes);
94    if (size > kMaxTotalSize) {
95        return false;
96    }
97
98    return true;
99}
100
101SkSurface_Raster::SkSurface_Raster(const SkImageInfo& info, void* pixels, size_t rb,
102                                   void (*releaseProc)(void* pixels, void* context), void* context,
103                                   const SkSurfaceProps* props)
104    : INHERITED(info, props)
105{
106    fBitmap.installPixels(info, pixels, rb, nullptr, releaseProc, context);
107    fRowBytes = 0;              // don't need to track the rowbytes
108    fWeOwnThePixels = false;    // We are "Direct"
109}
110
111SkSurface_Raster::SkSurface_Raster(sk_sp<SkPixelRef> pr, const SkSurfaceProps* props)
112    : INHERITED(pr->info().width(), pr->info().height(), props)
113{
114    const SkImageInfo& info = pr->info();
115
116    fBitmap.setInfo(info, pr->rowBytes());
117    fRowBytes = pr->rowBytes(); // we track this, so that subsequent re-allocs will match
118    fBitmap.setPixelRef(std::move(pr), 0, 0);
119    fWeOwnThePixels = true;
120}
121
122SkCanvas* SkSurface_Raster::onNewCanvas() { return new SkCanvas(fBitmap, this->props()); }
123
124sk_sp<SkSurface> SkSurface_Raster::onNewSurface(const SkImageInfo& info) {
125    return SkSurface::MakeRaster(info, &this->props());
126}
127
128void SkSurface_Raster::onDraw(SkCanvas* canvas, SkScalar x, SkScalar y,
129                              const SkPaint* paint) {
130    canvas->drawBitmap(fBitmap, x, y, paint);
131}
132
133sk_sp<SkImage> SkSurface_Raster::onNewImageSnapshot() {
134    SkCopyPixelsMode cpm = kIfMutable_SkCopyPixelsMode;
135    if (fWeOwnThePixels) {
136        // SkImage_raster requires these pixels are immutable for its full lifetime.
137        // We'll undo this via onRestoreBackingMutability() if we can avoid the COW.
138        if (SkPixelRef* pr = fBitmap.pixelRef()) {
139            pr->setTemporarilyImmutable();
140        }
141    } else {
142        cpm = kAlways_SkCopyPixelsMode;
143    }
144
145    // Our pixels are in memory, so read access on the snapshot SkImage could be cheap.
146    // Lock the shared pixel ref to ensure peekPixels() is usable.
147    return SkMakeImageFromRasterBitmap(fBitmap, cpm);
148}
149
150void SkSurface_Raster::onRestoreBackingMutability() {
151    SkASSERT(!this->hasCachedImage());  // Shouldn't be any snapshots out there.
152    if (SkPixelRef* pr = fBitmap.pixelRef()) {
153        pr->restoreMutability();
154    }
155}
156
157void SkSurface_Raster::onCopyOnWrite(ContentChangeMode mode) {
158    // are we sharing pixelrefs with the image?
159    sk_sp<SkImage> cached(this->refCachedImage());
160    SkASSERT(cached);
161    if (SkBitmapImageGetPixelRef(cached.get()) == fBitmap.pixelRef()) {
162        SkASSERT(fWeOwnThePixels);
163        if (kDiscard_ContentChangeMode == mode) {
164            fBitmap.allocPixels();
165        } else {
166            SkBitmap prev(fBitmap);
167            fBitmap.allocPixels();
168            prev.lockPixels();
169            SkASSERT(prev.info() == fBitmap.info());
170            SkASSERT(prev.rowBytes() == fBitmap.rowBytes());
171            memcpy(fBitmap.getPixels(), prev.getPixels(), fBitmap.getSafeSize());
172        }
173        SkASSERT(fBitmap.rowBytes() == fRowBytes);  // be sure we always use the same value
174
175        // Now fBitmap is a deep copy of itself (and therefore different from
176        // what is being used by the image. Next we update the canvas to use
177        // this as its backend, so we can't modify the image's pixels anymore.
178        SkASSERT(this->getCachedCanvas());
179        this->getCachedCanvas()->getDevice()->replaceBitmapBackendForRasterSurface(fBitmap);
180    }
181}
182
183///////////////////////////////////////////////////////////////////////////////
184
185sk_sp<SkSurface> SkSurface::MakeRasterDirectReleaseProc(const SkImageInfo& info, void* pixels,
186        size_t rb, void (*releaseProc)(void* pixels, void* context), void* context,
187        const SkSurfaceProps* props) {
188    if (nullptr == releaseProc) {
189        context = nullptr;
190    }
191    if (!SkSurface_Raster::Valid(info, rb)) {
192        return nullptr;
193    }
194    if (nullptr == pixels) {
195        return nullptr;
196    }
197
198    return sk_make_sp<SkSurface_Raster>(info, pixels, rb, releaseProc, context, props);
199}
200
201sk_sp<SkSurface> SkSurface::MakeRasterDirect(const SkImageInfo& info, void* pixels, size_t rowBytes,
202                                             const SkSurfaceProps* props) {
203    return MakeRasterDirectReleaseProc(info, pixels, rowBytes, nullptr, nullptr, props);
204}
205
206sk_sp<SkSurface> SkSurface::MakeRaster(const SkImageInfo& info, size_t rowBytes,
207                                       const SkSurfaceProps* props) {
208    if (!SkSurface_Raster::Valid(info)) {
209        return nullptr;
210    }
211
212    sk_sp<SkPixelRef> pr(SkMallocPixelRef::NewZeroed(info, rowBytes, nullptr));
213    if (!pr) {
214        return nullptr;
215    }
216    if (rowBytes) {
217        SkASSERT(pr->rowBytes() == rowBytes);
218    }
219    return sk_make_sp<SkSurface_Raster>(std::move(pr), props);
220}
221