1
2/*
3 * Copyright 2010 Google Inc.
4 *
5 * Use of this source code is governed by a BSD-style license that can be
6 * found in the LICENSE file.
7 */
8
9
10
11#include "SkGrPixelRef.h"
12
13#include "GrContext.h"
14#include "GrTexture.h"
15#include "SkBitmapCache.h"
16#include "SkGr.h"
17#include "SkRect.h"
18
19// since we call lockPixels recursively on fBitmap, we need a distinct mutex,
20// to avoid deadlock with the default one provided by SkPixelRef.
21SK_DECLARE_STATIC_MUTEX(gROLockPixelsPixelRefMutex);
22
23SkROLockPixelsPixelRef::SkROLockPixelsPixelRef(const SkImageInfo& info)
24    : INHERITED(info, &gROLockPixelsPixelRefMutex) {}
25
26SkROLockPixelsPixelRef::~SkROLockPixelsPixelRef() {}
27
28bool SkROLockPixelsPixelRef::onNewLockPixels(LockRec* rec) {
29    fBitmap.reset();
30//    SkDebugf("---------- calling readpixels in support of lockpixels\n");
31    if (!this->onReadPixels(&fBitmap, NULL)) {
32        SkDebugf("SkROLockPixelsPixelRef::onLockPixels failed!\n");
33        return false;
34    }
35    fBitmap.lockPixels();
36    if (NULL == fBitmap.getPixels()) {
37        return false;
38    }
39
40    rec->fPixels = fBitmap.getPixels();
41    rec->fColorTable = NULL;
42    rec->fRowBytes = fBitmap.rowBytes();
43    return true;
44}
45
46void SkROLockPixelsPixelRef::onUnlockPixels() {
47    fBitmap.unlockPixels();
48}
49
50bool SkROLockPixelsPixelRef::onLockPixelsAreWritable() const {
51    return false;
52}
53
54///////////////////////////////////////////////////////////////////////////////
55
56static SkGrPixelRef* copy_to_new_texture_pixelref(GrTexture* texture, SkColorType dstCT,
57                                                  SkColorProfileType dstPT, const SkIRect* subset) {
58    if (NULL == texture || kUnknown_SkColorType == dstCT) {
59        return NULL;
60    }
61    GrContext* context = texture->getContext();
62    if (NULL == context) {
63        return NULL;
64    }
65    GrSurfaceDesc desc;
66
67    SkIRect srcRect;
68
69    if (!subset) {
70        desc.fWidth  = texture->width();
71        desc.fHeight = texture->height();
72        srcRect = SkIRect::MakeWH(texture->width(), texture->height());
73    } else {
74        SkASSERT(SkIRect::MakeWH(texture->width(), texture->height()).contains(*subset));
75        // Create a new texture that is the size of subset.
76        desc.fWidth = subset->width();
77        desc.fHeight = subset->height();
78        srcRect = *subset;
79    }
80    desc.fFlags = kRenderTarget_GrSurfaceFlag;
81    desc.fConfig = SkImageInfo2GrPixelConfig(dstCT, kPremul_SkAlphaType, dstPT);
82
83    GrTexture* dst = context->textureProvider()->createTexture(desc, false, NULL, 0);
84    if (NULL == dst) {
85        return NULL;
86    }
87
88    // Blink is relying on the above copy being sent to GL immediately in the case when the source
89    // is a WebGL canvas backing store. We could have a TODO to remove this flush flag, but we have
90    // a larger TODO to remove SkGrPixelRef entirely.
91    context->copySurface(dst->asRenderTarget(), texture, srcRect, SkIPoint::Make(0,0),
92                         GrContext::kFlushWrites_PixelOp);
93
94    SkImageInfo info = SkImageInfo::Make(desc.fWidth, desc.fHeight, dstCT, kPremul_SkAlphaType,
95                                         dstPT);
96    SkGrPixelRef* pixelRef = SkNEW_ARGS(SkGrPixelRef, (info, dst));
97    SkSafeUnref(dst);
98    return pixelRef;
99}
100
101///////////////////////////////////////////////////////////////////////////////
102
103SkGrPixelRef::SkGrPixelRef(const SkImageInfo& info, GrSurface* surface) : INHERITED(info) {
104    // For surfaces that are both textures and render targets, the texture owns the
105    // render target but not vice versa. So we ref the texture to keep both alive for
106    // the lifetime of this pixel ref.
107    fSurface = SkSafeRef(surface->asTexture());
108    if (NULL == fSurface) {
109        fSurface = SkSafeRef(surface);
110    }
111
112    if (fSurface) {
113        SkASSERT(info.width() <= fSurface->width());
114        SkASSERT(info.height() <= fSurface->height());
115    }
116}
117
118SkGrPixelRef::~SkGrPixelRef() {
119    SkSafeUnref(fSurface);
120}
121
122GrTexture* SkGrPixelRef::getTexture() {
123    if (fSurface) {
124        return fSurface->asTexture();
125    }
126    return NULL;
127}
128
129SkPixelRef* SkGrPixelRef::deepCopy(SkColorType dstCT, SkColorProfileType dstPT,
130                                   const SkIRect* subset) {
131    if (NULL == fSurface) {
132        return NULL;
133    }
134
135    // Note that when copying a render-target-backed pixel ref, we
136    // return a texture-backed pixel ref instead.  This is because
137    // render-target pixel refs are usually created in conjunction with
138    // a GrTexture owned elsewhere (e.g., SkGpuDevice), and cannot live
139    // independently of that texture.  Texture-backed pixel refs, on the other
140    // hand, own their GrTextures, and are thus self-contained.
141    return copy_to_new_texture_pixelref(fSurface->asTexture(), dstCT, dstPT, subset);
142}
143
144static bool tryAllocBitmapPixels(SkBitmap* bitmap) {
145    SkBitmap::Allocator* allocator = SkBitmapCache::GetAllocator();
146    if (NULL != allocator) {
147        return allocator->allocPixelRef(bitmap, 0);
148    } else {
149        // DiscardableMemory is not available, fallback to default allocator
150        return bitmap->tryAllocPixels();
151    }
152}
153
154bool SkGrPixelRef::onReadPixels(SkBitmap* dst, const SkIRect* subset) {
155    if (NULL == fSurface || fSurface->wasDestroyed()) {
156        return false;
157    }
158
159    SkIRect bounds;
160    if (subset) {
161        bounds = *subset;
162    } else {
163        bounds = SkIRect::MakeWH(this->info().width(), this->info().height());
164    }
165
166    //Check the cache
167    if(!SkBitmapCache::Find(this->getGenerationID(), bounds, dst)) {
168        //Cache miss
169
170        SkBitmap cachedBitmap;
171        cachedBitmap.setInfo(this->info().makeWH(bounds.width(), bounds.height()));
172
173        // If we can't alloc the pixels, then fail
174        if (!tryAllocBitmapPixels(&cachedBitmap)) {
175            return false;
176        }
177
178        // Try to read the pixels from the surface
179        void* buffer = cachedBitmap.getPixels();
180        bool readPixelsOk = fSurface->readPixels(bounds.fLeft, bounds.fTop,
181                                bounds.width(), bounds.height(),
182                                kSkia8888_GrPixelConfig,
183                                buffer, cachedBitmap.rowBytes());
184
185        if (!readPixelsOk) {
186            return false;
187        }
188
189        // If we are here, pixels were read correctly from the surface.
190        cachedBitmap.setImmutable();
191        //Add to the cache
192        SkBitmapCache::Add(this, bounds, cachedBitmap);
193
194        dst->swap(cachedBitmap);
195    }
196
197    return true;
198
199}
200