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add gamma/sRGB to SkImageInfo

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BUG=skia:
R=bungeman@google.com, bsalomon@google.com

Author: reed@google.com

Review URL: https://codereview.chromium.org/514753002
This commit is contained in:
reed 2014-08-28 05:56:37 -07:00 committed by Commit bot
parent 9d9a6d2463
commit 615c369777
4 changed files with 240 additions and 45 deletions
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1
gyp/tests.gypi
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@ -119,6 +119,7 @@
'../tests/ImageDecodingTest.cpp',
'../tests/ImageFilterTest.cpp',
'../tests/ImageGeneratorTest.cpp',
'../tests/ImageInfoTest.cpp',
'../tests/ImageIsOpaqueTest.cpp',
'../tests/ImageNewShaderTest.cpp',
'../tests/InfRectTest.cpp',

88
include/core/SkImageInfo.h
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@ -136,36 +136,69 @@ bool SkColorTypeValidateAlphaType(SkColorType colorType, SkAlphaType alphaType,
* Describe an image's dimensions and pixel type.
*/
struct SkImageInfo {
public:
SkImageInfo() {}
int fWidth;
int fHeight;
SkColorType fColorType;
SkAlphaType fAlphaType;
private:
enum Profile {
kUnknown_Profile,
kSRGB_Profile,
kExponential_Profile,
};
uint32_t fProfile;
float fGamma;
SkImageInfo(int width, int height, SkColorType ct, SkAlphaType at, Profile p, float g)
: fWidth(width)
, fHeight(height)
, fColorType(ct)
, fAlphaType(at)
, fProfile(p)
, fGamma(g)
{}
public:
/*
* Return an info with the specified attributes, tagged as sRGB. Note that if the requested
* color type does not make sense with sRGB (e.g. kAlpha_8) then the sRGB request is ignored.
*
* You can call isSRGB() on the returned info to determine if the request was fulfilled.
*/
static SkImageInfo MakeSRGB(int width, int height, SkColorType ct, SkAlphaType at);
/*
* Return an info with the specified attributes, tagged with a specific gamma.
* Note that if the requested gamma is unsupported for the requested color type, then the gamma
* value will be set to 1.0 (the default).
*
* You can call gamma() to query the resulting gamma value.
*/
static SkImageInfo MakeWithGamma(int width, int height, SkColorType ct, SkAlphaType at,
float gamma);
static SkImageInfo Make(int width, int height, SkColorType ct, SkAlphaType at) {
SkImageInfo info = {
width, height, ct, at
};
return info;
return MakeWithGamma(width, height, ct, at, 1);
}
/**
* Sets colortype to the native ARGB32 type.
*/
static SkImageInfo MakeN32(int width, int height, SkAlphaType at) {
SkImageInfo info = {
width, height, kN32_SkColorType, at
};
return info;
return SkImageInfo(width, height, kN32_SkColorType, at, kExponential_Profile, 1);
}
/**
* Sets colortype to the native ARGB32 type, and the alphatype to premul.
*/
static SkImageInfo MakeN32Premul(int width, int height) {
SkImageInfo info = {
width, height, kN32_SkColorType, kPremul_SkAlphaType
};
return info;
return SkImageInfo(width, height, kN32_SkColorType, kPremul_SkAlphaType,
kExponential_Profile, 1);
}
/**
@ -176,24 +209,17 @@ struct SkImageInfo {
}
static SkImageInfo MakeA8(int width, int height) {
SkImageInfo info = {
width, height, kAlpha_8_SkColorType, kPremul_SkAlphaType
};
return info;
return SkImageInfo(width, height, kAlpha_8_SkColorType, kPremul_SkAlphaType,
kUnknown_Profile, 0);
}
static SkImageInfo MakeUnknown(int width, int height) {
SkImageInfo info = {
width, height, kUnknown_SkColorType, kIgnore_SkAlphaType
};
return info;
return SkImageInfo(width, height, kUnknown_SkColorType, kIgnore_SkAlphaType,
kUnknown_Profile, 0);
}
static SkImageInfo MakeUnknown() {
SkImageInfo info = {
0, 0, kUnknown_SkColorType, kIgnore_SkAlphaType
};
return info;
return SkImageInfo(0, 0, kUnknown_SkColorType, kIgnore_SkAlphaType, kUnknown_Profile, 0);
}
int width() const { return fWidth; }
@ -236,8 +262,11 @@ struct SkImageInfo {
return 0 != memcmp(this, &other, sizeof(other));
}
// DEPRECATED : use the static Unflatten
void unflatten(SkReadBuffer&);
void flatten(SkWriteBuffer&) const;
static SkImageInfo Unflatten(SkReadBuffer&);
int64_t getSafeSize64(size_t rowBytes) const {
if (0 == fHeight) {
@ -256,6 +285,17 @@ struct SkImageInfo {
}
SkDEBUGCODE(void validate() const;)
/**
* If the Info was tagged to be sRGB, return true, else return false.
*/
bool isSRGB() const { return kSRGB_Profile == fProfile; }
/**
* If this was tagged with an explicit gamma value, return that value, else return 0.
* If this was tagged as sRGB, return 0.
*/
float gamma() const { return fGamma; }
};
#endif

132
src/core/SkImageInfo.cpp
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@ -9,34 +9,53 @@
#include "SkReadBuffer.h"
#include "SkWriteBuffer.h"
static bool alpha_type_is_valid(SkAlphaType alphaType) {
return (alphaType >= 0) && (alphaType <= kLastEnum_SkAlphaType);
static bool color_type_supports_sRGB(SkColorType colorType) {
switch (colorType) {
case kRGBA_8888_SkColorType:
case kBGRA_8888_SkColorType:
return true;
default:
return false;
}
}
static bool color_type_is_valid(SkColorType colorType) {
return (colorType >= 0) && (colorType <= kLastEnum_SkColorType);
static bool color_type_supports_gamma(SkColorType colorType) {
switch (colorType) {
case kRGBA_8888_SkColorType:
case kBGRA_8888_SkColorType:
// case kLuminance ...
return true;
default:
return false;
}
}
void SkImageInfo::unflatten(SkReadBuffer& buffer) {
fWidth = buffer.read32();
fHeight = buffer.read32();
uint32_t packed = buffer.read32();
SkASSERT(0 == (packed >> 16));
fAlphaType = (SkAlphaType)((packed >> 8) & 0xFF);
fColorType = (SkColorType)((packed >> 0) & 0xFF);
buffer.validate(alpha_type_is_valid(fAlphaType) &&
color_type_is_valid(fColorType));
static float pin_gamma_to_legal(float gamma) {
if (!SkScalarIsFinite(gamma)) {
return 1;
}
// these limits are just made up -- feel free to change them within reason
const float min_gamma = 0.01f;
const float max_gamma = 4.0;
return SkScalarPin(gamma, min_gamma, max_gamma);
}
void SkImageInfo::flatten(SkWriteBuffer& buffer) const {
buffer.write32(fWidth);
buffer.write32(fHeight);
SkImageInfo SkImageInfo::MakeSRGB(int width, int height, SkColorType ct, SkAlphaType at) {
Profile p = color_type_supports_sRGB(ct) ? kSRGB_Profile : kUnknown_Profile;
return SkImageInfo(width, height, ct, at, p, 0);
}
SkASSERT(0 == (fAlphaType & ~0xFF));
SkASSERT(0 == (fColorType & ~0xFF));
uint32_t packed = (fAlphaType << 8) | fColorType;
buffer.write32(packed);
SkImageInfo SkImageInfo::MakeWithGamma(int width, int height, SkColorType ct, SkAlphaType at,
float gamma) {
Profile p;
if (color_type_supports_gamma(ct)) {
gamma = pin_gamma_to_legal(gamma);
p = kExponential_Profile;
} else {
p = kUnknown_Profile;
gamma = 0;
}
return SkImageInfo(width, height, ct, at, p, gamma);
}
bool SkColorTypeValidateAlphaType(SkColorType colorType, SkAlphaType alphaType,
@ -69,3 +88,74 @@ bool SkColorTypeValidateAlphaType(SkColorType colorType, SkAlphaType alphaType,
}
return true;
}
void SkImageInfo::unflatten(SkReadBuffer& buffer) {
*this = Unflatten(buffer);
}
////////////////////////////////////////////////////////////////////////////////////////////
static bool alpha_type_is_valid(SkAlphaType alphaType) {
return (alphaType >= 0) && (alphaType <= kLastEnum_SkAlphaType);
}
static bool color_type_is_valid(SkColorType colorType) {
return (colorType >= 0) && (colorType <= kLastEnum_SkColorType);
}
static float igamma_to_gamma(int gamma3dot9) {
return gamma3dot9 / 512.0f;
}
static unsigned gamma_to_igamma(float gamma) {
SkASSERT(gamma >= 0 && gamma < 8);
int igamma = SkScalarRoundToInt(gamma * 512);
SkASSERT(igamma >= 0 && igamma <= 0xFFF);
return igamma;
}
SkImageInfo SkImageInfo::Unflatten(SkReadBuffer& buffer) {
int width = buffer.read32();
int height = buffer.read32();
uint32_t packed = buffer.read32();
SkColorType ct = (SkColorType)((packed >> 0) & 0xFF); // 8 bits for colortype
SkAlphaType at = (SkAlphaType)((packed >> 8) & 0xFF); // 8 bits for alphatype
if (!alpha_type_is_valid(at) || !color_type_is_valid(ct)) {
return MakeUnknown();
}
// Earlier formats always stored 0 in the upper 16 bits. That corresponds to
// days before we had gamma/profile. That happens to correspond to kUnknown_Profile,
// which means we can just ignore the gamma value anyways.
//
int iprofile = ((packed >> 16) & 0xF); // 4 bits for profile
switch (iprofile) {
case kUnknown_Profile:
return Make(width, height, ct, at);
case kSRGB_Profile:
return MakeSRGB(width, height, ct, at);
case kExponential_Profile: {
int igamma = packed >> 20; // 12 bits for gamma 3.9
float gamma = igamma_to_gamma(igamma);
return MakeWithGamma(width, height, ct, at, gamma);
}
default:
(void)buffer.validate(false);
return MakeUnknown();
}
}
void SkImageInfo::flatten(SkWriteBuffer& buffer) const {
buffer.write32(fWidth);
buffer.write32(fHeight);
SkASSERT(0 == (fColorType & ~0xFF)); // 8 bits for colortype
SkASSERT(0 == (fAlphaType & ~0xFF)); // 8 bits for alphatype
SkASSERT(0 == (fProfile & ~0xF)); // 4 bits for profile
int igamma = gamma_to_igamma(fGamma); // 12 bits for gamma (if needed)
uint32_t packed = (igamma << 20) | (fProfile << 16) | (fAlphaType << 8) | fColorType;
buffer.write32(packed);
}

64
tests/ImageInfoTest.cpp Normal file
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@ -0,0 +1,64 @@
/*
* Copyright 2014 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkImageInfo.h"
#include "Test.h"
struct ImageInfoRec {
int fWidth;
int fHeight;
SkColorType fColorType;
SkAlphaType fAlphaType;
float fGamma;
bool fIsSRGB;
};
static void check_info(skiatest::Reporter* reporter,
const ImageInfoRec& expected, const SkImageInfo& info) {
REPORTER_ASSERT(reporter, info.width() == expected.fWidth);
REPORTER_ASSERT(reporter, info.height() == expected.fHeight);
REPORTER_ASSERT(reporter, info.colorType() == expected.fColorType);
REPORTER_ASSERT(reporter, info.alphaType() == expected.fAlphaType);
REPORTER_ASSERT(reporter, info.gamma() == expected.fGamma);
REPORTER_ASSERT(reporter, info.isSRGB() == expected.fIsSRGB);
}
DEF_TEST(ImageInfo, reporter) {
const float nan = SK_ScalarNaN;
const float nice_gamma = 1.5f;
const int W = 100;
const int H = 200;
SkImageInfo info;
const ImageInfoRec rec[] = {
{ 0, 0, kUnknown_SkColorType, kIgnore_SkAlphaType, 0, false }, // MakeUnknown()
{ W, H, kUnknown_SkColorType, kIgnore_SkAlphaType, 0, false }, // MakeUnknown(...)
{ W, H, kN32_SkColorType, kPremul_SkAlphaType, 1, false }, // MakeN32Premul(...)
{ W, H, kN32_SkColorType, kOpaque_SkAlphaType, 1, false }, // MakeN32(...)
{ W, H, kAlpha_8_SkColorType, kPremul_SkAlphaType, 0, false }, // MakeA8()
{ W, H, kRGBA_8888_SkColorType, kUnpremul_SkAlphaType, 1, false }, // Make()
{ W, H, kBGRA_8888_SkColorType, kPremul_SkAlphaType, 1, false }, // Make()
{ W, H, kBGRA_8888_SkColorType, kPremul_SkAlphaType, 0, true }, // MakeSRGB()
{ W, H, kN32_SkColorType, kPremul_SkAlphaType, 1, false }, // MakeWithGamma() NaN
{ W, H, kAlpha_8_SkColorType, kPremul_SkAlphaType, 0, false }, // MakeWithGamma() bad ct for gamma
{ W, H, kN32_SkColorType, kPremul_SkAlphaType, nice_gamma, false }, // MakeWithGamma() good
};
check_info(reporter, rec[ 0], SkImageInfo::MakeUnknown());
check_info(reporter, rec[ 1], SkImageInfo::MakeUnknown(W, H));
check_info(reporter, rec[ 2], SkImageInfo::MakeN32Premul(W, H));
check_info(reporter, rec[ 3], SkImageInfo::MakeN32(W, H, rec[3].fAlphaType));
check_info(reporter, rec[ 4], SkImageInfo::MakeA8(W, H));
check_info(reporter, rec[ 5], SkImageInfo::Make(W, H, rec[5].fColorType, rec[5].fAlphaType));
check_info(reporter, rec[ 6], SkImageInfo::Make(W, H, rec[6].fColorType, rec[6].fAlphaType));
check_info(reporter, rec[ 7], SkImageInfo::MakeSRGB(W, H, rec[7].fColorType, rec[7].fAlphaType));
check_info(reporter, rec[ 8], SkImageInfo::MakeWithGamma(W, H, rec[8].fColorType, rec[8].fAlphaType, nan));
check_info(reporter, rec[ 9], SkImageInfo::MakeWithGamma(W, H, rec[9].fColorType, rec[9].fAlphaType, nice_gamma));
check_info(reporter, rec[10], SkImageInfo::MakeWithGamma(W, H, rec[10].fColorType, rec[10].fAlphaType, rec[10].fGamma));
}