SkImage_Generator.cpp revision 982eb7f377a0c771345276558072deb2fcea0d3e 
1/*
2 * Copyright 2015 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 "SkImage_Base.h"
9#include "SkBitmap.h"
10#include "SkCanvas.h"
11#include "SkData.h"
12#include "SkImageCacherator.h"
13#include "SkImagePriv.h"
14#include "SkPixelRef.h"
15#include "SkSurface.h"
16
17class SkImage_Generator : public SkImage_Base {
18public:
19    SkImage_Generator(SkImageCacherator* cache)
20        : INHERITED(cache->info().width(), cache->info().height(), cache->uniqueID())
21        , fCache(cache) // take ownership
22    {}
23
24    virtual SkImageInfo onImageInfo() const override {
25        return fCache->info();
26    }
27
28    bool onReadPixels(const SkImageInfo&, void*, size_t, int srcX, int srcY, CachingHint) const override;
29    SkImageCacherator* peekCacherator() const override { return fCache; }
30    SkData* onRefEncoded(GrContext*) const override;
31    bool isOpaque() const override { return fCache->info().isOpaque(); }
32    sk_sp<SkImage> onMakeSubset(const SkIRect&) const override;
33    bool getROPixels(SkBitmap*, CachingHint) const override;
34    GrTexture* asTextureRef(GrContext*, const GrTextureParams&,
35                            SkSourceGammaTreatment) const override;
36    bool onIsLazyGenerated() const override { return true; }
37
38private:
39    SkAutoTDelete<SkImageCacherator> fCache;
40
41    typedef SkImage_Base INHERITED;
42};
43
44///////////////////////////////////////////////////////////////////////////////
45
46bool SkImage_Generator::onReadPixels(const SkImageInfo& dstInfo, void* dstPixels, size_t dstRB,
47                                     int srcX, int srcY, CachingHint chint) const {
48    SkBitmap bm;
49    if (kDisallow_CachingHint == chint) {
50        if (fCache->lockAsBitmapOnlyIfAlreadyCached(&bm)) {
51            return bm.readPixels(dstInfo, dstPixels, dstRB, srcX, srcY);
52        } else {
53            // Try passing the caller's buffer directly down to the generator. If this fails we
54            // may still succeed in the general case, as the generator may prefer some other
55            // config, which we could then convert via SkBitmap::readPixels.
56            if (fCache->directGeneratePixels(dstInfo, dstPixels, dstRB, srcX, srcY)) {
57                return true;
58            }
59            // else fall through
60        }
61    }
62
63    if (this->getROPixels(&bm, chint)) {
64        return bm.readPixels(dstInfo, dstPixels, dstRB, srcX, srcY);
65    }
66    return false;
67}
68
69SkData* SkImage_Generator::onRefEncoded(GrContext* ctx) const {
70    return fCache->refEncoded(ctx);
71}
72
73bool SkImage_Generator::getROPixels(SkBitmap* bitmap, CachingHint chint) const {
74    return fCache->lockAsBitmap(bitmap, this, chint);
75}
76
77GrTexture* SkImage_Generator::asTextureRef(GrContext* ctx, const GrTextureParams& params,
78                                           SkSourceGammaTreatment gammaTreatment) const {
79    return fCache->lockAsTexture(ctx, params, gammaTreatment, this);
80}
81
82sk_sp<SkImage> SkImage_Generator::onMakeSubset(const SkIRect& subset) const {
83    // TODO: make this lazy, by wrapping the subset inside a new generator or something
84    // For now, we do effectively what we did before, make it a raster
85
86    const SkImageInfo info = SkImageInfo::MakeN32(subset.width(), subset.height(),
87                                      this->isOpaque() ? kOpaque_SkAlphaType : kPremul_SkAlphaType);
88    auto surface(SkSurface::MakeRaster(info));
89    if (!surface) {
90        return nullptr;
91    }
92    surface->getCanvas()->clear(0);
93    surface->getCanvas()->drawImage(this, SkIntToScalar(-subset.x()), SkIntToScalar(-subset.y()),
94                                    nullptr);
95    return surface->makeImageSnapshot();
96}
97
98sk_sp<SkImage> SkImage::MakeFromGenerator(SkImageGenerator* generator, const SkIRect* subset) {
99    if (!generator) {
100        return nullptr;
101    }
102    SkImageCacherator* cache = SkImageCacherator::NewFromGenerator(generator, subset);
103    if (!cache) {
104        return nullptr;
105    }
106    return sk_make_sp<SkImage_Generator>(cache);
107}
108