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/*
* Copyright 2017 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkColorFilter.h"
#include "SkColorSpaceXformer.h"
#include "SkColorSpaceXformPriv.h"
#include "SkDrawLooper.h"
#include "SkGradientShader.h"
#include "SkImage.h"
#include "SkImage_Base.h"
#include "SkImageFilter.h"
#include "SkImagePriv.h"
#include "SkShaderBase.h"
SkColorSpaceXformer::SkColorSpaceXformer(sk_sp<SkColorSpace> dst,
std::unique_ptr<SkColorSpaceXform> fromSRGB)
: fDst(std::move(dst))
, fFromSRGB(std::move(fromSRGB))
, fReentryCount(0) {}
SkColorSpaceXformer::~SkColorSpaceXformer() {}
std::unique_ptr<SkColorSpaceXformer> SkColorSpaceXformer::Make(sk_sp<SkColorSpace> dst) {
std::unique_ptr<SkColorSpaceXform> fromSRGB = SkMakeColorSpaceXform(
SkColorSpace::MakeSRGB().get(), dst.get());
return fromSRGB
? std::unique_ptr<SkColorSpaceXformer>(new SkColorSpaceXformer(std::move(dst),
std::move(fromSRGB)))
: nullptr;
}
// So what's up with these caches?
//
// We want to cache transformed objects for a couple of reasons:
//
// 1) to avoid redundant work - the inputs are a DAG, not a tree (e.g. same SkImage drawn multiple
// times in a SkPicture), so if we blindly recurse we could end up transforming the same objects
// repeatedly.
//
// 2) to avoid topology changes - we want the output to remain isomorphic with the input -- this is
// particularly important for image filters (to maintain their original DAG structure in order
// to not defeat their own/internal caching), but also for avoiding unnecessary cloning
// (e.g. duplicated SkImages allocated for the example in #1 above).
//
// The caching scope is naturaly bound by the lifetime of the SkColorSpaceXformer object, but
// clients may choose to not discard xformers immediately - in which case, caching indefinitely
// is problematic. The solution is to limit the cache scope to the top level apply() call
// (i.e. we only keep cached objects alive while transforming).
class SkColorSpaceXformer::AutoCachePurge {
public:
AutoCachePurge(SkColorSpaceXformer* xformer)
: fXformer(xformer) {
fXformer->fReentryCount++;
}
~AutoCachePurge() {
SkASSERT(fXformer->fReentryCount > 0);
if (--fXformer->fReentryCount == 0) {
fXformer->purgeCaches();
}
}
private:
SkColorSpaceXformer* fXformer;
};
template <typename T>
sk_sp<T> SkColorSpaceXformer::cachedApply(const T* src, Cache<T>* cache,
sk_sp<T> (*applyFunc)(const T*, SkColorSpaceXformer*)) {
if (!src) {
return nullptr;
}
auto key = sk_ref_sp(const_cast<T*>(src));
if (auto* xformed = cache->find(key)) {
return sk_ref_sp(xformed->get());
}
auto xformed = applyFunc(src, this);
cache->set(std::move(key), xformed);
return xformed;
}
void SkColorSpaceXformer::purgeCaches() {
fImageCache.reset();
fColorFilterCache.reset();
fImageFilterCache.reset();
}
sk_sp<SkImage> SkColorSpaceXformer::apply(const SkImage* src) {
const AutoCachePurge autoPurge(this);
return this->cachedApply<SkImage>(src, &fImageCache,
[](const SkImage* img, SkColorSpaceXformer* xformer) {
return img->makeColorSpace(xformer->fDst);
});
}
sk_sp<SkImage> SkColorSpaceXformer::apply(const SkBitmap& src) {
const AutoCachePurge autoPurge(this);
sk_sp<SkImage> image = SkMakeImageFromRasterBitmap(src, kNever_SkCopyPixelsMode);
if (!image) {
return nullptr;
}
sk_sp<SkImage> xformed = image->makeColorSpace(fDst);
// We want to be sure we don't let the kNever_SkCopyPixelsMode image escape this stack frame.
SkASSERT(xformed != image);
return xformed;
}
sk_sp<SkColorFilter> SkColorSpaceXformer::apply(const SkColorFilter* colorFilter) {
const AutoCachePurge autoPurge(this);
return this->cachedApply<SkColorFilter>(colorFilter, &fColorFilterCache,
[](const SkColorFilter* f, SkColorSpaceXformer* xformer) {
return f->makeColorSpace(xformer);
});
}
sk_sp<SkImageFilter> SkColorSpaceXformer::apply(const SkImageFilter* imageFilter) {
const AutoCachePurge autoPurge(this);
return this->cachedApply<SkImageFilter>(imageFilter, &fImageFilterCache,
[](const SkImageFilter* f, SkColorSpaceXformer* xformer) {
return f->makeColorSpace(xformer);
});
}
sk_sp<SkShader> SkColorSpaceXformer::apply(const SkShader* shader) {
const AutoCachePurge autoPurge(this);
return as_SB(shader)->makeColorSpace(this);
}
void SkColorSpaceXformer::apply(SkColor* xformed, const SkColor* srgb, int n) {
SkAssertResult(fFromSRGB->apply(SkColorSpaceXform::kBGRA_8888_ColorFormat, xformed,
SkColorSpaceXform::kBGRA_8888_ColorFormat, srgb,
n, kUnpremul_SkAlphaType));
}
SkColor SkColorSpaceXformer::apply(SkColor srgb) {
SkColor xformed;
this->apply(&xformed, &srgb, 1);
return xformed;
}
SkPaint SkColorSpaceXformer::apply(const SkPaint& src) {
const AutoCachePurge autoPurge(this);
SkPaint dst = src;
// All SkColorSpaces have the same black point.
if (src.getColor() & 0xffffff) {
dst.setColor(this->apply(src.getColor()));
}
if (auto shader = src.getShader()) {
dst.setShader(this->apply(shader));
}
if (auto cf = src.getColorFilter()) {
dst.setColorFilter(this->apply(cf));
}
if (auto looper = src.getDrawLooper()) {
dst.setDrawLooper(looper->makeColorSpace(this));
}
if (auto imageFilter = src.getImageFilter()) {
dst.setImageFilter(this->apply(imageFilter));
}
return dst;
}
SkCanvas::Lattice SkColorSpaceXformer::apply(const SkCanvas::Lattice& lattice,
SkColor* colorBuffer, int count) {
if (count) {
this->apply(colorBuffer, lattice.fColors, count);
return {lattice.fXDivs, lattice.fYDivs, lattice.fRectTypes,
lattice.fXCount, lattice.fYCount, lattice.fBounds, colorBuffer};
}
return lattice;
}
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