skia2/gm/encode-srgb.cpp
Matt Sarett 84014f03a9 Respect SkColorSpace in SkPNGImageEncoder
This only changes behavior when the input SkBitmap/SkPixmap is
tagged with a non-null SkColorSpace.  Android tags their bitmaps
as sRGB when linear blending is enabled.  So this only changes
behavior in Android when linear blending is turned on.
*If linear blending is turned on, this will do a color correct
 encode (which is the desired behavior).
*If linear blending is turned off, this will do a legacy encode.

TODO: Add support for F16.
TODO: Add color space support to WEBP.
TODO: Tag encoded images with ICC profiles (when it makes sense).

BUG=skia:

Change-Id: Idd8a2836371d24a453d953e6fe2e76a87751be96
Reviewed-on: https://skia-review.googlesource.com/6498
Reviewed-by: Brian Osman <brianosman@google.com>
Reviewed-by: Leon Scroggins <scroggo@google.com>
Reviewed-by: Mike Klein <mtklein@chromium.org>
Commit-Queue: Matt Sarett <msarett@google.com>
2017-01-10 18:26:26 +00:00

142 lines
4.6 KiB
C++

/*
* Copyright 2016 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "gm.h"
#include "Resources.h"
#include "SkCanvas.h"
#include "SkCodec.h"
#include "SkData.h"
#include "SkImageEncoderPriv.h"
#include "SkPM4f.h"
#include "SkSRGB.h"
namespace skiagm {
static const int imageWidth = 128;
static const int imageHeight = 128;
static inline int div_round_up(int a, int b) {
return (a + b - 1) / b;
}
static void make_index8(SkBitmap* bitmap, SkAlphaType alphaType, sk_sp<SkColorSpace> colorSpace) {
const SkColor colors[] = {
0x800000FF, 0x8000FF00, 0x80FF0000, 0x80FFFF00,
};
auto toPMColor = [alphaType, colorSpace](SkColor color) {
// In the unpremul case, just convert to SkPMColor ordering.
if (kUnpremul_SkAlphaType == alphaType) {
return SkSwizzle_BGRA_to_PMColor(color);
}
// Linear premultiply.
if (colorSpace) {
uint32_t result;
Sk4f pmFloat = SkColor4f::FromColor(color).premul().to4f_pmorder();
SkNx_cast<uint8_t>(sk_linear_to_srgb_needs_trunc(pmFloat)).store(&result);
result = (result & 0x00FFFFFF) | (color & 0xFF000000);
return result;
}
// Legacy premultiply.
return SkPreMultiplyColor(color);
};
// Note that these are not necessarily premultiplied, but they are platform byte ordering.
SkPMColor pmColors[SK_ARRAY_COUNT(colors)];
for (int i = 0; i < (int) SK_ARRAY_COUNT(colors); i++) {
pmColors[i] = toPMColor(colors[i]);
}
sk_sp<SkColorTable> colorTable(new SkColorTable(pmColors, SK_ARRAY_COUNT(pmColors)));
SkImageInfo info = SkImageInfo::Make(imageWidth, imageHeight, kIndex_8_SkColorType,
alphaType, colorSpace);
bitmap->allocPixels(info, nullptr, colorTable.get());
for (int y = 0; y < imageHeight; y++) {
for (int x = 0; x < imageWidth; x++) {
*bitmap->getAddr8(x, y) = (x / div_round_up(imageWidth, 2)) +
(y / div_round_up(imageHeight, 3));
}
}
}
static void make(SkBitmap* bitmap, SkColorType colorType, SkAlphaType alphaType,
sk_sp<SkColorSpace> colorSpace) {
if (kIndex_8_SkColorType == colorType) {
make_index8(bitmap, alphaType, colorSpace);
return;
}
sk_sp<SkData> data = GetResourceAsData("color_wheel.png");
std::unique_ptr<SkCodec> codec(SkCodec::NewFromData(data));
SkImageInfo dstInfo = codec->getInfo().makeColorType(colorType)
.makeAlphaType(alphaType)
.makeColorSpace(colorSpace);
bitmap->allocPixels(dstInfo);
codec->getPixels(dstInfo, bitmap->getPixels(), bitmap->rowBytes());
}
static sk_sp<SkData> encode_data(const SkBitmap& bitmap) {
SkAutoLockPixels autoLockPixels(bitmap);
SkPixmap src;
if (!bitmap.peekPixels(&src)) {
return nullptr;
}
SkDynamicMemoryWStream buf;
SkEncodeOptions options;
if (bitmap.colorSpace()) {
options.fPremulBehavior = SkEncodeOptions::PremulBehavior::kGammaCorrect;
}
SkAssertResult(SkEncodeImageAsPNG(&buf, src, options));
return buf.detachAsData();
}
class EncodeSRGBGM : public GM {
public:
EncodeSRGBGM() {}
protected:
SkString onShortName() override {
return SkString("encode-srgb");
}
SkISize onISize() override {
return SkISize::Make(imageWidth * 2, imageHeight * 4);
}
void onDraw(SkCanvas* canvas) override {
const SkColorType colorTypes[] = { kN32_SkColorType, kIndex_8_SkColorType, };
const SkAlphaType alphaTypes[] = { kUnpremul_SkAlphaType, kPremul_SkAlphaType, };
const sk_sp<SkColorSpace> colorSpaces[] = {
nullptr, SkColorSpace::MakeNamed(SkColorSpace::kSRGB_Named),
};
SkBitmap bitmap;
for (SkColorType colorType : colorTypes) {
for (SkAlphaType alphaType : alphaTypes) {
canvas->save();
for (sk_sp<SkColorSpace> colorSpace : colorSpaces) {
make(&bitmap, colorType, alphaType, colorSpace);
auto image = SkImage::MakeFromEncoded(encode_data(bitmap));
canvas->drawImage(image.get(), 0.0f, 0.0f);
canvas->translate((float) imageWidth, 0.0f);
}
canvas->restore();
canvas->translate(0.0f, (float) imageHeight);
}
}
}
private:
typedef GM INHERITED;
};
DEF_GM( return new EncodeSRGBGM; )
}