SkSurface_Raster.cpp revision b947625800a26194fcf63d7b57dadb1a63677f6a 
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 SkImage::Info&, size_t rb = kIgnoreRowBytesValue);
19
20    SkSurface_Raster(const SkImage::Info&, void*, size_t rb);
21    SkSurface_Raster(const SkImage::Info&, SkPixelRef*, size_t rb);
22
23    virtual SkCanvas* onNewCanvas() SK_OVERRIDE;
24    virtual SkSurface* onNewSurface(const SkImage::Info&) SK_OVERRIDE;
25    virtual SkImage* onNewImageShapshot() SK_OVERRIDE;
26    virtual void onDraw(SkCanvas*, SkScalar x, SkScalar y,
27                        const SkPaint*) SK_OVERRIDE;
28    virtual void onCopyOnWrite(SkImage*, SkCanvas*) SK_OVERRIDE;
29
30private:
31    SkBitmap    fBitmap;
32    bool        fWeOwnThePixels;
33
34    typedef SkSurface_Base INHERITED;
35};
36
37///////////////////////////////////////////////////////////////////////////////
38
39bool SkSurface_Raster::Valid(const SkImage::Info& info, size_t rowBytes) {
40    static const size_t kMaxTotalSize = SK_MaxS32;
41
42    bool isOpaque;
43    SkBitmap::Config config = SkImageInfoToBitmapConfig(info, &isOpaque);
44
45    int shift = 0;
46    switch (config) {
47        case SkBitmap::kA8_Config:
48            shift = 0;
49            break;
50        case SkBitmap::kRGB_565_Config:
51            shift = 1;
52            break;
53        case SkBitmap::kARGB_8888_Config:
54            shift = 2;
55            break;
56        default:
57            return false;
58    }
59
60    // TODO: examine colorspace
61
62    if (kIgnoreRowBytesValue == rowBytes) {
63        return true;
64    }
65
66    uint64_t minRB = (uint64_t)info.fWidth << shift;
67    if (minRB > rowBytes) {
68        return false;
69    }
70
71    size_t alignedRowBytes = rowBytes >> shift << shift;
72    if (alignedRowBytes != rowBytes) {
73        return false;
74    }
75
76    uint64_t size = (uint64_t)info.fHeight * rowBytes;
77    if (size > kMaxTotalSize) {
78        return false;
79    }
80
81    return true;
82}
83
84SkSurface_Raster::SkSurface_Raster(const SkImage::Info& info, void* pixels, size_t rb)
85        : INHERITED(info.fWidth, info.fHeight) {
86    bool isOpaque;
87    SkBitmap::Config config = SkImageInfoToBitmapConfig(info, &isOpaque);
88
89    fBitmap.setConfig(config, info.fWidth, info.fHeight, rb);
90    fBitmap.setPixels(pixels);
91    fBitmap.setIsOpaque(isOpaque);
92    fWeOwnThePixels = false;    // We are "Direct"
93}
94
95SkSurface_Raster::SkSurface_Raster(const SkImage::Info& info, SkPixelRef* pr, size_t rb)
96        : INHERITED(info.fWidth, info.fHeight) {
97    bool isOpaque;
98    SkBitmap::Config config = SkImageInfoToBitmapConfig(info, &isOpaque);
99
100    fBitmap.setConfig(config, info.fWidth, info.fHeight, rb);
101    fBitmap.setPixelRef(pr);
102    fBitmap.setIsOpaque(isOpaque);
103    fWeOwnThePixels = true;
104
105    if (!isOpaque) {
106        fBitmap.eraseColor(0);
107    }
108}
109
110SkCanvas* SkSurface_Raster::onNewCanvas() {
111    return SkNEW_ARGS(SkCanvas, (fBitmap));
112}
113
114SkSurface* SkSurface_Raster::onNewSurface(const SkImage::Info& info) {
115    return SkSurface::NewRaster(info);
116}
117
118void SkSurface_Raster::onDraw(SkCanvas* canvas, SkScalar x, SkScalar y,
119                              const SkPaint* paint) {
120    canvas->drawBitmap(fBitmap, x, y, paint);
121}
122
123SkImage* SkSurface_Raster::onNewImageShapshot() {
124    return SkNewImageFromBitmap(fBitmap, fWeOwnThePixels);
125}
126
127void SkSurface_Raster::onCopyOnWrite(SkImage* image, SkCanvas* canvas) {
128    // are we sharing pixelrefs with the image?
129    if (SkBitmapImageGetPixelRef(image) == fBitmap.pixelRef()) {
130        SkASSERT(fWeOwnThePixels);
131        SkBitmap prev(fBitmap);
132        prev.deepCopyTo(&fBitmap, prev.config());
133        // Now fBitmap is a deep copy of itself (and therefore different from
134        // what is being used by the image. Next we update the canvas to use
135        // this as its backend, so we can't modify the image's pixels anymore.
136        canvas->getDevice()->replaceBitmapBackendForRasterSurface(fBitmap);
137    }
138}
139
140///////////////////////////////////////////////////////////////////////////////
141
142SkSurface* SkSurface::NewRasterDirect(const SkImage::Info& info, void* pixels, size_t rowBytes) {
143    if (!SkSurface_Raster::Valid(info, rowBytes)) {
144        return NULL;
145    }
146    if (NULL == pixels) {
147        return NULL;
148    }
149
150    return SkNEW_ARGS(SkSurface_Raster, (info, pixels, rowBytes));
151}
152
153SkSurface* SkSurface::NewRaster(const SkImage::Info& info) {
154    if (!SkSurface_Raster::Valid(info)) {
155        return NULL;
156    }
157
158    static const size_t kMaxTotalSize = SK_MaxS32;
159    size_t rowBytes = SkImageMinRowBytes(info);
160    uint64_t size64 = (uint64_t)info.fHeight * rowBytes;
161    if (size64 > kMaxTotalSize) {
162        return NULL;
163    }
164
165    size_t size = (size_t)size64;
166    void* pixels = sk_malloc_throw(size);
167    if (NULL == pixels) {
168        return NULL;
169    }
170
171    SkAutoTUnref<SkPixelRef> pr(SkNEW_ARGS(SkMallocPixelRef, (pixels, size, NULL, true)));
172    return SkNEW_ARGS(SkSurface_Raster, (info, pr, rowBytes));
173}
174
175