AuroraMiddleware/skia2
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Refactor parsing and storage of SkGammas

Browse Source 
Benefits:
(1) Parses and stores gamma tags in a single allocation.
(2) Recognizes equal gamma tags to skip parsing work and
    save memory.

Non-Benefits:
(1) Not less complicated.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2117773002

Review-Url: https://codereview.chromium.org/2117773002
This commit is contained in:
msarett 2016-07-20 11:44:42 -07:00 committed by Commit bot
parent de996a0df7
commit 2ea944c2b7
7 changed files with 878 additions and 807 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

38
src/core/SkColorSpace.cpp
View File

@ -22,9 +22,10 @@ SkColorSpace_Base::SkColorSpace_Base(GammaNamed gammaNamed, const SkMatrix44& to
, fProfileData(nullptr)
{}
SkColorSpace_Base::SkColorSpace_Base(sk_sp<SkColorLookUpTable> colorLUT, sk_sp<SkGammas> gammas,
const SkMatrix44& toXYZD50, sk_sp<SkData> profileData)
: INHERITED(kNonStandard_GammaNamed, toXYZD50, kUnknown_Named)
SkColorSpace_Base::SkColorSpace_Base(sk_sp<SkColorLookUpTable> colorLUT, GammaNamed gammaNamed,
sk_sp<SkGammas> gammas, const SkMatrix44& toXYZD50,
sk_sp<SkData> profileData)
: INHERITED(gammaNamed, toXYZD50, kUnknown_Named)
, fColorLUT(std::move(colorLUT))
, fGammas(std::move(gammas))
, fProfileData(std::move(profileData))
@ -68,16 +69,31 @@ static bool xyz_almost_equal(const SkMatrix44& toXYZD50, const float* standard)
}
sk_sp<SkColorSpace> SkColorSpace_Base::NewRGB(float values[3], const SkMatrix44& toXYZD50) {
SkGammaCurve curves[3];
set_gamma_value(&curves[0], values[0]);
set_gamma_value(&curves[1], values[1]);
set_gamma_value(&curves[2], values[2]);
if (0.0f > values[0] || 0.0f > values[1] || 0.0f > values[2]) {
return nullptr;
}
GammaNamed gammaNamed = kNonStandard_GammaNamed;
if (color_space_almost_equal(2.2f, values[0]) &&
color_space_almost_equal(2.2f, values[1]) &&
color_space_almost_equal(2.2f, values[2])) {
gammaNamed = k2Dot2Curve_GammaNamed;
} else if (color_space_almost_equal(1.0f, values[0]) &&
color_space_almost_equal(1.0f, values[1]) &&
color_space_almost_equal(1.0f, values[2])) {
gammaNamed = kLinear_GammaNamed;
}
GammaNamed gammaNamed = SkGammas::Named(curves);
if (kNonStandard_GammaNamed == gammaNamed) {
sk_sp<SkGammas> gammas(new SkGammas(std::move(curves[0]), std::move(curves[1]),
std::move(curves[2])));
return sk_sp<SkColorSpace>(new SkColorSpace_Base(nullptr, gammas, toXYZD50, nullptr));
sk_sp<SkGammas> gammas = sk_sp<SkGammas>(new SkGammas());
gammas->fRedType = SkGammas::Type::kValue_Type;
gammas->fGreenType = SkGammas::Type::kValue_Type;
gammas->fBlueType = SkGammas::Type::kValue_Type;
gammas->fRedData.fValue = values[0];
gammas->fGreenData.fValue = values[1];
gammas->fBlueData.fValue = values[2];
return sk_sp<SkColorSpace>(new SkColorSpace_Base(nullptr, kNonStandard_GammaNamed, gammas,
toXYZD50, nullptr));
}
return SkColorSpace_Base::NewRGB(gammaNamed, toXYZD50);

13
src/core/SkColorSpacePriv.h
View File

@ -10,16 +10,3 @@
inline bool color_space_almost_equal(float a, float b) {
return SkTAbs(a - b) < 0.01f;
}
inline void set_gamma_value(SkGammaCurve* gamma, float value) {
if (color_space_almost_equal(2.2f, value)) {
gamma->fNamed = SkColorSpace::k2Dot2Curve_GammaNamed;
} else if (color_space_almost_equal(1.0f, value)) {
gamma->fNamed = SkColorSpace::kLinear_GammaNamed;
} else if (color_space_almost_equal(0.0f, value)) {
SkColorSpacePrintf("Treating invalid zero gamma as linear.");
gamma->fNamed = SkColorSpace::kLinear_GammaNamed;
} else {
gamma->fValue = value;
}
}

409
src/core/SkColorSpaceXform.cpp
View File

@ -264,11 +264,11 @@ static uint8_t clamp_normalized_float_to_byte(float v) {
}
}
static void build_table_linear_to_gamma(uint8_t* outTable, int outTableSize, float exponent) {
static void build_table_linear_to_gamma(uint8_t* outTable, float exponent) {
float toGammaExp = 1.0f / exponent;
for (int i = 0; i < outTableSize; i++) {
float x = ((float) i) * (1.0f / ((float) (outTableSize - 1)));
for (int i = 0; i < SkDefaultXform::kDstGammaTableSize; i++) {
float x = ((float) i) * (1.0f / ((float) (SkDefaultXform::kDstGammaTableSize - 1)));
outTable[i] = clamp_normalized_float_to_byte(powf(x, toGammaExp));
}
}
@ -276,7 +276,7 @@ static void build_table_linear_to_gamma(uint8_t* outTable, int outTableSize, flo
// Inverse table lookup. Ex: what index corresponds to the input value? This will
// have strange results when the table is non-increasing. But any sane gamma
// function will be increasing.
static float inverse_interp_lut(float input, float* table, int tableSize) {
static float inverse_interp_lut(float input, const float* table, int tableSize) {
if (input <= table[0]) {
return table[0];
} else if (input >= table[tableSize - 1]) {
@ -299,10 +299,10 @@ static float inverse_interp_lut(float input, float* table, int tableSize) {
return 0.0f;
}
static void build_table_linear_to_gamma(uint8_t* outTable, int outTableSize, float* inTable,
static void build_table_linear_to_gamma(uint8_t* outTable, const float* inTable,
int inTableSize) {
for (int i = 0; i < outTableSize; i++) {
float x = ((float) i) * (1.0f / ((float) (outTableSize - 1)));
for (int i = 0; i < SkDefaultXform::kDstGammaTableSize; i++) {
float x = ((float) i) * (1.0f / ((float) (SkDefaultXform::kDstGammaTableSize - 1)));
float y = inverse_interp_lut(x, inTable, inTableSize);
outTable[i] = clamp_normalized_float_to_byte(y);
}
@ -339,10 +339,10 @@ static float inverse_parametric(float x, float g, float a, float b, float c, flo
return (powf(x - c, 1.0f / g) - b) / a;
}
static void build_table_linear_to_gamma(uint8_t* outTable, int outTableSize, float g, float a,
static void build_table_linear_to_gamma(uint8_t* outTable, float g, float a,
float b, float c, float d, float e, float f) {
for (int i = 0; i < outTableSize; i++) {
float x = ((float) i) * (1.0f / ((float) (outTableSize - 1)));
for (int i = 0; i < SkDefaultXform::kDstGammaTableSize; i++) {
float x = ((float) i) * (1.0f / ((float) (SkDefaultXform::kDstGammaTableSize - 1)));
float y = inverse_parametric(x, g, a, b, c, d, e, f);
outTable[i] = clamp_normalized_float_to_byte(y);
}
@ -350,6 +350,102 @@ static void build_table_linear_to_gamma(uint8_t* outTable, int outTableSize, flo
///////////////////////////////////////////////////////////////////////////////////////////////////
template <typename T>
struct GammaFns {
const T* fSRGBTable;
const T* f2Dot2Table;
void (*fBuildFromValue)(T*, float);
void (*fBuildFromTable)(T*, const float*, int);
void (*fBuildFromParam)(T*, float, float, float, float, float, float, float);
};
static const GammaFns<float> kToLinear {
sk_linear_from_srgb,
sk_linear_from_2dot2,
&build_table_linear_from_gamma,
&build_table_linear_from_gamma,
&build_table_linear_from_gamma,
};
static const GammaFns<uint8_t> kFromLinear {
linear_to_srgb,
linear_to_2dot2,
&build_table_linear_to_gamma,
&build_table_linear_to_gamma,
&build_table_linear_to_gamma,
};
// Build tables to transform src gamma to linear.
template <typename T>
static void build_gamma_tables(const T* outGammaTables[3], T* gammaTableStorage, int gammaTableSize,
const sk_sp<SkColorSpace>& space, const GammaFns<T>& fns) {
switch (space->gammaNamed()) {
case SkColorSpace::kSRGB_GammaNamed:
outGammaTables[0] = outGammaTables[1] = outGammaTables[2] = fns.fSRGBTable;
break;
case SkColorSpace::k2Dot2Curve_GammaNamed:
outGammaTables[0] = outGammaTables[1] = outGammaTables[2] = fns.f2Dot2Table;
break;
case SkColorSpace::kLinear_GammaNamed:
(*fns.fBuildFromValue)(gammaTableStorage, 1.0f);
outGammaTables[0] = outGammaTables[1] = outGammaTables[2] = gammaTableStorage;
break;
default: {
const SkGammas* gammas = as_CSB(space)->gammas();
SkASSERT(gammas);
for (int i = 0; i < 3; i++) {
if (i > 0) {
// Check if this curve matches the first curve. In this case, we can
// share the same table pointer. This should almost always be true.
// I've never seen a profile where all three gamma curves didn't match.
// But it is possible that they won't.
if (0 == memcmp(&gammas->data(0), &gammas->data(i), sizeof(SkGammas::Data))) {
outGammaTables[i] = outGammaTables[0];
continue;
}
}
if (gammas->isNamed(i)) {
switch (gammas->data(i).fNamed) {
case SkColorSpace::kSRGB_GammaNamed:
outGammaTables[i] = fns.fSRGBTable;
break;
case SkColorSpace::k2Dot2Curve_GammaNamed:
outGammaTables[i] = fns.f2Dot2Table;
break;
case SkColorSpace::kLinear_GammaNamed:
(*fns.fBuildFromValue)(&gammaTableStorage[i * gammaTableSize], 1.0f);
outGammaTables[i] = &gammaTableStorage[i * gammaTableSize];
break;
default:
SkASSERT(false);
break;
}
} else if (gammas->isValue(i)) {
(*fns.fBuildFromValue)(&gammaTableStorage[i * gammaTableSize],
gammas->data(i).fValue);
outGammaTables[i] = &gammaTableStorage[i * gammaTableSize];
} else if (gammas->isTable(i)) {
(*fns.fBuildFromTable)(&gammaTableStorage[i * gammaTableSize], gammas->table(i),
gammas->data(i).fTable.fSize);
outGammaTables[i] = &gammaTableStorage[i * gammaTableSize];
} else {
SkASSERT(gammas->isParametric(i));
const SkGammas::Params& params = gammas->params(i);
(*fns.fBuildFromParam)(&gammaTableStorage[i * gammaTableSize], params.fG,
params.fA, params.fB, params.fC, params.fD, params.fE,
params.fF);
outGammaTables[i] = &gammaTableStorage[i * gammaTableSize];
}
}
}
}
}
///////////////////////////////////////////////////////////////////////////////////////////////////
std::unique_ptr<SkColorSpaceXform> SkColorSpaceXform::New(const sk_sp<SkColorSpace>& srcSpace,
const sk_sp<SkColorSpace>& dstSpace) {
if (!srcSpace || !dstSpace) {
@ -420,150 +516,9 @@ SkFastXform<Dst>::SkFastXform(const sk_sp<SkColorSpace>& srcSpace, const SkMatri
const sk_sp<SkColorSpace>& dstSpace)
{
build_src_to_dst(fSrcToDst, srcToDst);
// Build tables to transform src gamma to linear.
switch (srcSpace->gammaNamed()) {
case SkColorSpace::kSRGB_GammaNamed:
fSrcGammaTables[0] = fSrcGammaTables[1] = fSrcGammaTables[2] = sk_linear_from_srgb;
break;
case SkColorSpace::k2Dot2Curve_GammaNamed:
fSrcGammaTables[0] = fSrcGammaTables[1] = fSrcGammaTables[2] = sk_linear_from_2dot2;
break;
case SkColorSpace::kLinear_GammaNamed:
build_table_linear_from_gamma(fSrcGammaTableStorage, 1.0f);
fSrcGammaTables[0] = fSrcGammaTables[1] = fSrcGammaTables[2] = fSrcGammaTableStorage;
break;
default: {
const SkGammas* gammas = as_CSB(srcSpace)->gammas();
SkASSERT(gammas);
for (int i = 0; i < 3; i++) {
const SkGammaCurve& curve = (*gammas)[i];
if (i > 0) {
// Check if this curve matches the first curve. In this case, we can
// share the same table pointer. Logically, this should almost always
// be true. I've never seen a profile where all three gamma curves
// didn't match. But it is possible that they won't.
// TODO (msarett):
// This comparison won't catch the case where each gamma curve has a
// pointer to its own look-up table, but the tables actually match.
// Should we perform a deep compare of gamma tables here? Or should
// we catch this when parsing the profile? Or should we not worry
// about a bit of redundant work?
if (curve.quickEquals((*gammas)[0])) {
fSrcGammaTables[i] = fSrcGammaTables[0];
continue;
}
}
if (curve.isNamed()) {
switch (curve.fNamed) {
case SkColorSpace::kSRGB_GammaNamed:
fSrcGammaTables[i] = sk_linear_from_srgb;
break;
case SkColorSpace::k2Dot2Curve_GammaNamed:
fSrcGammaTables[i] = sk_linear_from_2dot2;
break;
case SkColorSpace::kLinear_GammaNamed:
build_table_linear_from_gamma(&fSrcGammaTableStorage[i * 256], 1.0f);
fSrcGammaTables[i] = &fSrcGammaTableStorage[i * 256];
break;
default:
SkASSERT(false);
break;
}
} else if (curve.isValue()) {
build_table_linear_from_gamma(&fSrcGammaTableStorage[i * 256], curve.fValue);
fSrcGammaTables[i] = &fSrcGammaTableStorage[i * 256];
} else if (curve.isTable()) {
build_table_linear_from_gamma(&fSrcGammaTableStorage[i * 256],
curve.fTable.get(), curve.fTableSize);
fSrcGammaTables[i] = &fSrcGammaTableStorage[i * 256];
} else {
SkASSERT(curve.isParametric());
build_table_linear_from_gamma(&fSrcGammaTableStorage[i * 256], curve.fG,
curve.fA, curve.fB, curve.fC, curve.fD, curve.fE,
curve.fF);
fSrcGammaTables[i] = &fSrcGammaTableStorage[i * 256];
}
}
}
}
// Build tables to transform linear to dst gamma.
// FIXME (msarett):
// Should we spend all of this time bulding the dst gamma tables when the client only
// wants to convert to F16?
switch (dstSpace->gammaNamed()) {
case SkColorSpace::kSRGB_GammaNamed:
case SkColorSpace::k2Dot2Curve_GammaNamed:
break;
case SkColorSpace::kLinear_GammaNamed:
build_table_linear_to_gamma(fDstGammaTableStorage, kDstGammaTableSize, 1.0f);
fDstGammaTables[0] = fDstGammaTables[1] = fDstGammaTables[2] = fDstGammaTableStorage;
break;
default: {
const SkGammas* gammas = as_CSB(dstSpace)->gammas();
SkASSERT(gammas);
for (int i = 0; i < 3; i++) {
const SkGammaCurve& curve = (*gammas)[i];
if (i > 0) {
// Check if this curve matches the first curve. In this case, we can
// share the same table pointer. Logically, this should almost always
// be true. I've never seen a profile where all three gamma curves
// didn't match. But it is possible that they won't.
// TODO (msarett):
// This comparison won't catch the case where each gamma curve has a
// pointer to its own look-up table (but the tables actually match).
// Should we perform a deep compare of gamma tables here? Or should
// we catch this when parsing the profile? Or should we not worry
// about a bit of redundant work?
if (curve.quickEquals((*gammas)[0])) {
fDstGammaTables[i] = fDstGammaTables[0];
continue;
}
}
if (curve.isNamed()) {
switch (curve.fNamed) {
case SkColorSpace::kSRGB_GammaNamed:
fDstGammaTables[i] = linear_to_srgb;
break;
case SkColorSpace::k2Dot2Curve_GammaNamed:
fDstGammaTables[i] = linear_to_2dot2;
break;
case SkColorSpace::kLinear_GammaNamed:
build_table_linear_to_gamma(
&fDstGammaTableStorage[i * kDstGammaTableSize],
kDstGammaTableSize, 1.0f);
fDstGammaTables[i] = &fDstGammaTableStorage[i * kDstGammaTableSize];
break;
default:
SkASSERT(false);
break;
}
} else if (curve.isValue()) {
build_table_linear_to_gamma(&fDstGammaTableStorage[i * kDstGammaTableSize],
kDstGammaTableSize, curve.fValue);
fDstGammaTables[i] = &fDstGammaTableStorage[i * kDstGammaTableSize];
} else if (curve.isTable()) {
build_table_linear_to_gamma(&fDstGammaTableStorage[i * kDstGammaTableSize],
kDstGammaTableSize, curve.fTable.get(),
curve.fTableSize);
fDstGammaTables[i] = &fDstGammaTableStorage[i * kDstGammaTableSize];
} else {
SkASSERT(curve.isParametric());
build_table_linear_to_gamma(&fDstGammaTableStorage[i * kDstGammaTableSize],
kDstGammaTableSize, curve.fG, curve.fA, curve.fB,
curve.fC, curve.fD, curve.fE, curve.fF);
fDstGammaTables[i] = &fDstGammaTableStorage[i * kDstGammaTableSize];
}
}
}
}
build_gamma_tables(fSrcGammaTables, fSrcGammaTableStorage, 256, srcSpace, kToLinear);
build_gamma_tables(fDstGammaTables, fDstGammaTableStorage, SkDefaultXform::kDstGammaTableSize,
dstSpace, kFromLinear);
}
template <>
@ -601,149 +556,9 @@ SkDefaultXform::SkDefaultXform(const sk_sp<SkColorSpace>& srcSpace, const SkMatr
: fColorLUT(sk_ref_sp((SkColorLookUpTable*) as_CSB(srcSpace)->colorLUT()))
, fSrcToDst(srcToDst)
{
// Build tables to transform src gamma to linear.
switch (srcSpace->gammaNamed()) {
case SkColorSpace::kSRGB_GammaNamed:
fSrcGammaTables[0] = fSrcGammaTables[1] = fSrcGammaTables[2] = sk_linear_from_srgb;
break;
case SkColorSpace::k2Dot2Curve_GammaNamed:
fSrcGammaTables[0] = fSrcGammaTables[1] = fSrcGammaTables[2] = sk_linear_from_2dot2;
break;
case SkColorSpace::kLinear_GammaNamed:
build_table_linear_from_gamma(fSrcGammaTableStorage, 1.0f);
fSrcGammaTables[0] = fSrcGammaTables[1] = fSrcGammaTables[2] = fSrcGammaTableStorage;
break;
default: {
const SkGammas* gammas = as_CSB(srcSpace)->gammas();
SkASSERT(gammas);
for (int i = 0; i < 3; i++) {
const SkGammaCurve& curve = (*gammas)[i];
if (i > 0) {
// Check if this curve matches the first curve. In this case, we can
// share the same table pointer. Logically, this should almost always
// be true. I've never seen a profile where all three gamma curves
// didn't match. But it is possible that they won't.
// TODO (msarett):
// This comparison won't catch the case where each gamma curve has a
// pointer to its own look-up table, but the tables actually match.
// Should we perform a deep compare of gamma tables here? Or should
// we catch this when parsing the profile? Or should we not worry
// about a bit of redundant work?
if (curve.quickEquals((*gammas)[0])) {
fSrcGammaTables[i] = fSrcGammaTables[0];
continue;
}
}
if (curve.isNamed()) {
switch (curve.fNamed) {
case SkColorSpace::kSRGB_GammaNamed:
fSrcGammaTables[i] = sk_linear_from_srgb;
break;
case SkColorSpace::k2Dot2Curve_GammaNamed:
fSrcGammaTables[i] = sk_linear_from_2dot2;
break;
case SkColorSpace::kLinear_GammaNamed:
build_table_linear_from_gamma(&fSrcGammaTableStorage[i * 256], 1.0f);
fSrcGammaTables[i] = &fSrcGammaTableStorage[i * 256];
break;
default:
SkASSERT(false);
break;
}
} else if (curve.isValue()) {
build_table_linear_from_gamma(&fSrcGammaTableStorage[i * 256], curve.fValue);
fSrcGammaTables[i] = &fSrcGammaTableStorage[i * 256];
} else if (curve.isTable()) {
build_table_linear_from_gamma(&fSrcGammaTableStorage[i * 256],
curve.fTable.get(), curve.fTableSize);
fSrcGammaTables[i] = &fSrcGammaTableStorage[i * 256];
} else {
SkASSERT(curve.isParametric());
build_table_linear_from_gamma(&fSrcGammaTableStorage[i * 256], curve.fG,
curve.fA, curve.fB, curve.fC, curve.fD, curve.fE,
curve.fF);
fSrcGammaTables[i] = &fSrcGammaTableStorage[i * 256];
}
}
}
}
// Build tables to transform linear to dst gamma.
switch (dstSpace->gammaNamed()) {
case SkColorSpace::kSRGB_GammaNamed:
fDstGammaTables[0] = fDstGammaTables[1] = fDstGammaTables[2] = linear_to_srgb;
break;
case SkColorSpace::k2Dot2Curve_GammaNamed:
fDstGammaTables[0] = fDstGammaTables[1] = fDstGammaTables[2] = linear_to_2dot2;
break;
case SkColorSpace::kLinear_GammaNamed:
build_table_linear_to_gamma(fDstGammaTableStorage, kDstGammaTableSize, 1.0f);
fDstGammaTables[0] = fDstGammaTables[1] = fDstGammaTables[2] = fDstGammaTableStorage;
break;
default: {
const SkGammas* gammas = as_CSB(dstSpace)->gammas();
SkASSERT(gammas);
for (int i = 0; i < 3; i++) {
const SkGammaCurve& curve = (*gammas)[i];
if (i > 0) {
// Check if this curve matches the first curve. In this case, we can
// share the same table pointer. Logically, this should almost always
// be true. I've never seen a profile where all three gamma curves
// didn't match. But it is possible that they won't.
// TODO (msarett):
// This comparison won't catch the case where each gamma curve has a
// pointer to its own look-up table (but the tables actually match).
// Should we perform a deep compare of gamma tables here? Or should
// we catch this when parsing the profile? Or should we not worry
// about a bit of redundant work?
if (curve.quickEquals((*gammas)[0])) {
fDstGammaTables[i] = fDstGammaTables[0];
continue;
}
}
if (curve.isNamed()) {
switch (curve.fNamed) {
case SkColorSpace::kSRGB_GammaNamed:
fDstGammaTables[i] = linear_to_srgb;
break;
case SkColorSpace::k2Dot2Curve_GammaNamed:
fDstGammaTables[i] = linear_to_2dot2;
break;
case SkColorSpace::kLinear_GammaNamed:
build_table_linear_to_gamma(
&fDstGammaTableStorage[i * kDstGammaTableSize],
kDstGammaTableSize, 1.0f);
fDstGammaTables[i] = &fDstGammaTableStorage[i * kDstGammaTableSize];
break;
default:
SkASSERT(false);
break;
}
} else if (curve.isValue()) {
build_table_linear_to_gamma(&fDstGammaTableStorage[i * kDstGammaTableSize],
kDstGammaTableSize, curve.fValue);
fDstGammaTables[i] = &fDstGammaTableStorage[i * kDstGammaTableSize];
} else if (curve.isTable()) {
build_table_linear_to_gamma(&fDstGammaTableStorage[i * kDstGammaTableSize],
kDstGammaTableSize, curve.fTable.get(),
curve.fTableSize);
fDstGammaTables[i] = &fDstGammaTableStorage[i * kDstGammaTableSize];
} else {
SkASSERT(curve.isParametric());
build_table_linear_to_gamma(&fDstGammaTableStorage[i * kDstGammaTableSize],
kDstGammaTableSize, curve.fG, curve.fA, curve.fB,
curve.fC, curve.fD, curve.fE, curve.fF);
fDstGammaTables[i] = &fDstGammaTableStorage[i * kDstGammaTableSize];
}
}
}
}
build_gamma_tables(fSrcGammaTables, fSrcGammaTableStorage, 256, srcSpace, kToLinear);
build_gamma_tables(fDstGammaTables, fDstGammaTableStorage, SkDefaultXform::kDstGammaTableSize,
dstSpace, kFromLinear);
}
static float byte_to_float(uint8_t byte) {

3
src/core/SkColorSpaceXform.h
View File

@ -76,12 +76,11 @@ public:
void applyTo8888(SkPMColor* dst, const RGBA32* src, int len) const override;
void applyToF16(RGBAF16* dst, const RGBA32* src, int len) const override;
static constexpr int kDstGammaTableSize = 1024;
private:
SkDefaultXform(const sk_sp<SkColorSpace>& srcSpace, const SkMatrix44& srcToDst,
const sk_sp<SkColorSpace>& dstSpace);
static constexpr int kDstGammaTableSize = 1024;
sk_sp<SkColorLookUpTable> fColorLUT;
// May contain pointers into storage or pointers into precomputed tables.

202
src/core/SkColorSpace_Base.h
View File

@ -12,130 +12,106 @@
#include "SkData.h"
#include "SkTemplates.h"
struct SkGammaCurve {
bool isNamed() const {
bool result = (SkColorSpace::kNonStandard_GammaNamed != fNamed);
SkASSERT(!result || (0.0f == fValue));
SkASSERT(!result || (0 == fTableSize));
SkASSERT(!result || (0.0f == fG && 0.0f == fE));
return result;
}
struct SkGammas : SkRefCnt {
bool isValue() const {
bool result = (0.0f != fValue);
SkASSERT(!result || SkColorSpace::kNonStandard_GammaNamed == fNamed);
SkASSERT(!result || (0 == fTableSize));
SkASSERT(!result || (0.0f == fG && 0.0f == fE));
return result;
}
// There are four possible representations for gamma curves. kNone_Type is used
// as a placeholder until the struct is initialized. It is not a valid value.
enum class Type : uint8_t {
kNone_Type,
kNamed_Type,
kValue_Type,
kTable_Type,
kParam_Type,
};
bool isTable() const {
bool result = (0 != fTableSize);
SkASSERT(!result || SkColorSpace::kNonStandard_GammaNamed == fNamed);
SkASSERT(!result || (0.0f == fValue));
SkASSERT(!result || (0.0f == fG && 0.0f == fE));
SkASSERT(!result || fTable);
return result;
}
// Contains information for a gamma table.
struct Table {
int fSize;
size_t fOffset;
bool isParametric() const {
bool result = (0.0f != fG || 0.0f != fE);
SkASSERT(!result || SkColorSpace::kNonStandard_GammaNamed == fNamed);
SkASSERT(!result || (0.0f == fValue));
SkASSERT(!result || (0 == fTableSize));
return result;
}
// We have four different ways to represent gamma.
// (1) A known, named type:
SkColorSpace::GammaNamed fNamed;
// (2) A single value:
float fValue;
// (3) A lookup table:
uint32_t fTableSize;
std::unique_ptr<float[]> fTable;
// (4) Parameters for a curve:
// Y = (aX + b)^g + c for X >= d
// Y = eX + f otherwise
float fG;
float fA;
float fB;
float fC;
float fD;
float fE;
float fF;
SkGammaCurve()
: fNamed(SkColorSpace::kNonStandard_GammaNamed)
, fValue(0.0f)
, fTableSize(0)
, fTable(nullptr)
, fG(0.0f)
, fA(0.0f)
, fB(0.0f)
, fC(0.0f)
, fD(0.0f)
, fE(0.0f)
, fF(0.0f)
{}
bool quickEquals(const SkGammaCurve& that) const {
return (this->fNamed == that.fNamed) && (this->fValue == that.fValue) &&
(this->fTableSize == that.fTableSize) && (this->fTable == that.fTable) &&
(this->fG == that.fG) && (this->fA == that.fA) && (this->fB == that.fB) &&
(this->fC == that.fC) && (this->fD == that.fD) && (this->fE == that.fE) &&
(this->fF == that.fF);
}
};
struct SkGammas : public SkRefCnt {
public:
static SkColorSpace::GammaNamed Named(SkGammaCurve curves[3]) {
if (SkColorSpace::kLinear_GammaNamed == curves[0].fNamed &&
SkColorSpace::kLinear_GammaNamed == curves[1].fNamed &&
SkColorSpace::kLinear_GammaNamed == curves[2].fNamed)
{
return SkColorSpace::kLinear_GammaNamed;
const float* table(const SkGammas* base) const {
return SkTAddOffset<const float>(base, sizeof(SkGammas) + fOffset);
}
};
if (SkColorSpace::kSRGB_GammaNamed == curves[0].fNamed &&
SkColorSpace::kSRGB_GammaNamed == curves[1].fNamed &&
SkColorSpace::kSRGB_GammaNamed == curves[2].fNamed)
{
return SkColorSpace::kSRGB_GammaNamed;
// Contains the parameters for a parametric curve.
struct Params {
// Y = (aX + b)^g + c for X >= d
// Y = eX + f otherwise
float fG;
float fA;
float fB;
float fC;
float fD;
float fE;
float fF;
};
// Contains the actual gamma curve information. Should be interpreted
// based on the type of the gamma curve.
union Data {
Data()
: fTable{ 0, 0 }
{}
SkColorSpace::GammaNamed fNamed;
float fValue;
Table fTable;
size_t fParamOffset;
const Params& params(const SkGammas* base) const {
return *SkTAddOffset<const Params>(base, sizeof(SkGammas) + fParamOffset);
}
};
if (SkColorSpace::k2Dot2Curve_GammaNamed == curves[0].fNamed &&
SkColorSpace::k2Dot2Curve_GammaNamed == curves[1].fNamed &&
SkColorSpace::k2Dot2Curve_GammaNamed == curves[2].fNamed)
{
return SkColorSpace::k2Dot2Curve_GammaNamed;
}
return SkColorSpace::kNonStandard_GammaNamed;
}
const SkGammaCurve& operator[](int i) const {
bool isNamed(int i) const {
SkASSERT(0 <= i && i < 3);
return (&fRed)[i];
return (&fRedType)[i] == Type::kNamed_Type;
}
const SkGammaCurve fRed;
const SkGammaCurve fGreen;
const SkGammaCurve fBlue;
bool isValue(int i) const {
SkASSERT(0 <= i && i < 3);
return (&fRedType)[i] == Type::kValue_Type;
}
SkGammas(SkGammaCurve red, SkGammaCurve green, SkGammaCurve blue)
: fRed(std::move(red))
, fGreen(std::move(green))
, fBlue(std::move(blue))
bool isTable(int i) const {
SkASSERT(0 <= i && i < 3);
return (&fRedType)[i] == Type::kTable_Type;
}
bool isParametric(int i) const {
SkASSERT(0 <= i && i < 3);
return (&fRedType)[i] == Type::kParam_Type;
}
const Data& data(int i) const {
SkASSERT(0 <= i && i < 3);
return (&fRedData)[i];
}
const float* table(int i) const {
SkASSERT(isTable(i));
return (&fRedData)[i].fTable.table(this);
}
const Params& params(int i) const {
SkASSERT(isParametric(i));
return (&fRedData)[i].params(this);
}
SkGammas()
: fRedType(Type::kNone_Type)
, fGreenType(Type::kNone_Type)
, fBlueType(Type::kNone_Type)
{}
SkGammas() {}
friend class SkColorSpace;
// These fields should only be modified when initializing the struct.
Data fRedData;
Data fGreenData;
Data fBlueData;
Type fRedType;
Type fGreenType;
Type fBlueType;
};
struct SkColorLookUpTable : public SkRefCnt {
@ -173,8 +149,8 @@ private:
SkColorSpace_Base(GammaNamed gammaNamed, const SkMatrix44& toXYZ, Named named);
SkColorSpace_Base(sk_sp<SkColorLookUpTable> colorLUT, sk_sp<SkGammas> gammas,
const SkMatrix44& toXYZ, sk_sp<SkData> profileData);
SkColorSpace_Base(sk_sp<SkColorLookUpTable> colorLUT, GammaNamed gammaNamed,
sk_sp<SkGammas> gammas, const SkMatrix44& toXYZ, sk_sp<SkData> profileData);
sk_sp<SkColorLookUpTable> fColorLUT;
sk_sp<SkGammas> fGammas;

908
src/core/SkColorSpace_ICC.cpp
View File

@ -238,287 +238,384 @@ static bool load_xyz(float dst[3], const uint8_t* src, size_t len) {
static constexpr uint32_t kTAG_CurveType = SkSetFourByteTag('c', 'u', 'r', 'v');
static constexpr uint32_t kTAG_ParaCurveType = SkSetFourByteTag('p', 'a', 'r', 'a');
static bool load_gammas(SkGammaCurve* gammas, uint32_t numGammas, const uint8_t* src, size_t len) {
for (uint32_t i = 0; i < numGammas; i++) {
if (len < 12) {
// FIXME (msarett):
// We could potentially return false here after correctly parsing *some* of the
// gammas correctly. Should we somehow try to indicate a partial success?
SkColorSpacePrintf("gamma tag is too small (%d bytes)", len);
return false;
}
// We need to count the number of bytes in the tag, so we are able to move to the
// next tag on the next loop iteration.
size_t tagBytes;
uint32_t type = read_big_endian_uint(src);
switch (type) {
case kTAG_CurveType: {
uint32_t count = read_big_endian_uint(src + 8);
// tagBytes = 12 + 2 * count
// We need to do safe addition here to avoid integer overflow.
if (!safe_add(count, count, &tagBytes) ||
!safe_add((size_t) 12, tagBytes, &tagBytes))
{
SkColorSpacePrintf("Invalid gamma count");
return false;
}
if (0 == count) {
// Some tags require a gamma curve, but the author doesn't actually want
// to transform the data. In this case, it is common to see a curve with
// a count of 0.
gammas[i].fNamed = SkColorSpace::kLinear_GammaNamed;
break;
} else if (len < tagBytes) {
SkColorSpacePrintf("gamma tag is too small (%d bytes)", len);
return false;
}
const uint16_t* table = (const uint16_t*) (src + 12);
if (1 == count) {
// The table entry is the gamma (with a bias of 256).
float value = (read_big_endian_short((const uint8_t*) table)) / 256.0f;
set_gamma_value(&gammas[i], value);
SkColorSpacePrintf("gamma %g\n", value);
break;
}
// Check for frequently occurring sRGB curves.
// We do this by sampling a few values and see if they match our expectation.
// A more robust solution would be to compare each value in this curve against
// an sRGB curve to see if we remain below an error threshold. At this time,
// we haven't seen any images in the wild that make this kind of
// calculation necessary. We encounter identical gamma curves over and
// over again, but relatively few variations.
if (1024 == count) {
// The magic values were chosen because they match a very common sRGB
// gamma table and the less common Canon sRGB gamma table (which use
// different rounding rules).
if (0 == read_big_endian_short((const uint8_t*) &table[0]) &&
3366 == read_big_endian_short((const uint8_t*) &table[257]) &&
14116 == read_big_endian_short((const uint8_t*) &table[513]) &&
34318 == read_big_endian_short((const uint8_t*) &table[768]) &&
65535 == read_big_endian_short((const uint8_t*) &table[1023])) {
gammas[i].fNamed = SkColorSpace::kSRGB_GammaNamed;
break;
}
} else if (26 == count) {
// The magic values were chosen because they match a very common sRGB
// gamma table.
if (0 == read_big_endian_short((const uint8_t*) &table[0]) &&
3062 == read_big_endian_short((const uint8_t*) &table[6]) &&
12824 == read_big_endian_short((const uint8_t*) &table[12]) &&
31237 == read_big_endian_short((const uint8_t*) &table[18]) &&
65535 == read_big_endian_short((const uint8_t*) &table[25])) {
gammas[i].fNamed = SkColorSpace::kSRGB_GammaNamed;
break;
}
} else if (4096 == count) {
// The magic values were chosen because they match Nikon, Epson, and
// LCMS sRGB gamma tables (all of which use different rounding rules).
if (0 == read_big_endian_short((const uint8_t*) &table[0]) &&
950 == read_big_endian_short((const uint8_t*) &table[515]) &&
3342 == read_big_endian_short((const uint8_t*) &table[1025]) &&
14079 == read_big_endian_short((const uint8_t*) &table[2051]) &&
65535 == read_big_endian_short((const uint8_t*) &table[4095])) {
gammas[i].fNamed = SkColorSpace::kSRGB_GammaNamed;
break;
}
}
// Otherwise, fill in the interpolation table.
gammas[i].fTableSize = count;
gammas[i].fTable = std::unique_ptr<float[]>(new float[count]);
for (uint32_t j = 0; j < count; j++) {
gammas[i].fTable[j] =
(read_big_endian_short((const uint8_t*) &table[j])) / 65535.0f;
}
break;
}
case kTAG_ParaCurveType: {
enum ParaCurveType {
kExponential_ParaCurveType = 0,
kGAB_ParaCurveType = 1,
kGABC_ParaCurveType = 2,
kGABDE_ParaCurveType = 3,
kGABCDEF_ParaCurveType = 4,
};
// Determine the format of the parametric curve tag.
uint16_t format = read_big_endian_short(src + 8);
if (kExponential_ParaCurveType == format) {
tagBytes = 12 + 4;
if (len < tagBytes) {
SkColorSpacePrintf("gamma tag is too small (%d bytes)", len);
return false;
}
// Y = X^g
int32_t g = read_big_endian_int(src + 12);
set_gamma_value(&gammas[i], SkFixedToFloat(g));
} else {
// Here's where the real parametric gammas start. There are many
// permutations of the same equations.
//
// Y = (aX + b)^g + c for X >= d
// Y = eX + f otherwise
//
// We will fill in with zeros as necessary to always match the above form.
float g = 0.0f, a = 0.0f, b = 0.0f, c = 0.0f, d = 0.0f, e = 0.0f, f = 0.0f;
switch(format) {
case kGAB_ParaCurveType: {
tagBytes = 12 + 12;
if (len < tagBytes) {
SkColorSpacePrintf("gamma tag is too small (%d bytes)", len);
return false;
}
// Y = (aX + b)^g for X >= -b/a
// Y = 0 otherwise
g = SkFixedToFloat(read_big_endian_int(src + 12));
a = SkFixedToFloat(read_big_endian_int(src + 16));
if (0.0f == a) {
return false;
}
b = SkFixedToFloat(read_big_endian_int(src + 20));
d = -b / a;
break;
}
case kGABC_ParaCurveType:
tagBytes = 12 + 16;
if (len < tagBytes) {
SkColorSpacePrintf("gamma tag is too small (%d bytes)", len);
return false;
}
// Y = (aX + b)^g + c for X >= -b/a
// Y = c otherwise
g = SkFixedToFloat(read_big_endian_int(src + 12));
a = SkFixedToFloat(read_big_endian_int(src + 16));
if (0.0f == a) {
return false;
}
b = SkFixedToFloat(read_big_endian_int(src + 20));
c = SkFixedToFloat(read_big_endian_int(src + 24));
d = -b / a;
f = c;
break;
case kGABDE_ParaCurveType:
tagBytes = 12 + 20;
if (len < tagBytes) {
SkColorSpacePrintf("gamma tag is too small (%d bytes)", len);
return false;
}
// Y = (aX + b)^g for X >= d
// Y = cX otherwise
g = SkFixedToFloat(read_big_endian_int(src + 12));
a = SkFixedToFloat(read_big_endian_int(src + 16));
b = SkFixedToFloat(read_big_endian_int(src + 20));
d = SkFixedToFloat(read_big_endian_int(src + 28));
e = SkFixedToFloat(read_big_endian_int(src + 24));
break;
case kGABCDEF_ParaCurveType:
tagBytes = 12 + 28;
if (len < tagBytes) {
SkColorSpacePrintf("gamma tag is too small (%d bytes)", len);
return false;
}
// Y = (aX + b)^g + c for X >= d
// Y = eX + f otherwise
// NOTE: The ICC spec writes "cX" in place of "eX" but I think
// it's a typo.
g = SkFixedToFloat(read_big_endian_int(src + 12));
a = SkFixedToFloat(read_big_endian_int(src + 16));
b = SkFixedToFloat(read_big_endian_int(src + 20));
c = SkFixedToFloat(read_big_endian_int(src + 24));
d = SkFixedToFloat(read_big_endian_int(src + 28));
e = SkFixedToFloat(read_big_endian_int(src + 32));
f = SkFixedToFloat(read_big_endian_int(src + 36));
break;
default:
SkColorSpacePrintf("Invalid parametric curve type\n");
return false;
}
// Recognize and simplify a very common parametric representation of sRGB gamma.
if (color_space_almost_equal(0.9479f, a) &&
color_space_almost_equal(0.0521f, b) &&
color_space_almost_equal(0.0000f, c) &&
color_space_almost_equal(0.0405f, d) &&
color_space_almost_equal(0.0774f, e) &&
color_space_almost_equal(0.0000f, f) &&
color_space_almost_equal(2.4000f, g)) {
gammas[i].fNamed = SkColorSpace::kSRGB_GammaNamed;
} else {
// Fail on invalid gammas.
if (d <= 0.0f) {
// Y = (aX + b)^g + c for always
if (0.0f == a || 0.0f == g) {
SkColorSpacePrintf("A or G is zero, constant gamma function "
"is nonsense");
return false;
}
} else if (d >= 1.0f) {
// Y = eX + f for always
if (0.0f == e) {
SkColorSpacePrintf("E is zero, constant gamma function is "
"nonsense");
return false;
}
} else if ((0.0f == a || 0.0f == g) && 0.0f == e) {
SkColorSpacePrintf("A or G, and E are zero, constant gamma function "
"is nonsense");
return false;
}
gammas[i].fG = g;
gammas[i].fA = a;
gammas[i].fB = b;
gammas[i].fC = c;
gammas[i].fD = d;
gammas[i].fE = e;
gammas[i].fF = f;
}
}
break;
}
default:
SkColorSpacePrintf("Unsupported gamma tag type %d\n", type);
return false;
}
// Ensure that we have successfully read a gamma representation.
SkASSERT(gammas[i].isNamed() || gammas[i].isValue() || gammas[i].isTable() ||
gammas[i].isParametric());
// Adjust src and len if there is another gamma curve to load.
if (i != numGammas - 1) {
// Each curve is padded to 4-byte alignment.
tagBytes = SkAlign4(tagBytes);
if (len < tagBytes) {
return false;
}
src += tagBytes;
len -= tagBytes;
}
static SkGammas::Type set_gamma_value(SkGammas::Data* data, float value) {
if (color_space_almost_equal(2.2f, value)) {
data->fNamed = SkColorSpace::k2Dot2Curve_GammaNamed;
return SkGammas::Type::kNamed_Type;
}
return true;
if (color_space_almost_equal(1.0f, value)) {
data->fNamed = SkColorSpace::kLinear_GammaNamed;
return SkGammas::Type::kNamed_Type;
}
if (color_space_almost_equal(0.0f, value)) {
return SkGammas::Type::kNone_Type;
}
data->fValue = value;
return SkGammas::Type::kValue_Type;
}
static float read_big_endian_16_dot_16(const uint8_t buf[4]) {
// It just so happens that SkFixed is also 16.16!
return SkFixedToFloat(read_big_endian_int(buf));
}
/**
* @param outData Set to the appropriate value on success. If we have table or
* parametric gamma, it is the responsibility of the caller to set
* fOffset.
* @param outParams If this is a parametric gamma, this is set to the appropriate
* parameters on success.
* @param outTagBytes Will be set to the length of the tag on success.
* @src Pointer to tag data.
* @len Length of tag data in bytes.
*
* @return kNone_Type on failure, otherwise the type of the gamma tag.
*/
static SkGammas::Type parse_gamma(SkGammas::Data* outData, SkGammas::Params* outParams,
size_t* outTagBytes, const uint8_t* src, size_t len) {
if (len < 12) {
SkColorSpacePrintf("gamma tag is too small (%d bytes)", len);
return SkGammas::Type::kNone_Type;
}
// In the case of consecutive gamma tags, we need to count the number of bytes in the
// tag, so that we can move on to the next tag.
size_t tagBytes;
uint32_t type = read_big_endian_uint(src);
// Bytes 4-7 are reserved and should be set to zero.
switch (type) {
case kTAG_CurveType: {
uint32_t count = read_big_endian_uint(src + 8);
// tagBytes = 12 + 2 * count
// We need to do safe addition here to avoid integer overflow.
if (!safe_add(count, count, &tagBytes) ||
!safe_add((size_t) 12, tagBytes, &tagBytes))
{
SkColorSpacePrintf("Invalid gamma count");
return SkGammas::Type::kNone_Type;
}
if (len < tagBytes) {
SkColorSpacePrintf("gamma tag is too small (%d bytes)", len);
return SkGammas::Type::kNone_Type;
}
*outTagBytes = tagBytes;
if (0 == count) {
// Some tags require a gamma curve, but the author doesn't actually want
// to transform the data. In this case, it is common to see a curve with
// a count of 0.
outData->fNamed = SkColorSpace::kLinear_GammaNamed;
return SkGammas::Type::kNamed_Type;
}
const uint16_t* table = (const uint16_t*) (src + 12);
if (1 == count) {
// The table entry is the gamma (with a bias of 256).
float value = (read_big_endian_short((const uint8_t*) table)) / 256.0f;
SkColorSpacePrintf("gamma %g\n", value);
return set_gamma_value(outData, value);
}
// Check for frequently occurring sRGB curves.
// We do this by sampling a few values and see if they match our expectation.
// A more robust solution would be to compare each value in this curve against
// an sRGB curve to see if we remain below an error threshold. At this time,
// we haven't seen any images in the wild that make this kind of
// calculation necessary. We encounter identical gamma curves over and
// over again, but relatively few variations.
if (1024 == count) {
// The magic values were chosen because they match both the very common
// HP sRGB gamma table and the less common Canon sRGB gamma table (which use
// different rounding rules).
if (0 == read_big_endian_short((const uint8_t*) &table[0]) &&
3366 == read_big_endian_short((const uint8_t*) &table[257]) &&
14116 == read_big_endian_short((const uint8_t*) &table[513]) &&
34318 == read_big_endian_short((const uint8_t*) &table[768]) &&
65535 == read_big_endian_short((const uint8_t*) &table[1023])) {
outData->fNamed = SkColorSpace::kSRGB_GammaNamed;
return SkGammas::Type::kNamed_Type;
}
}
if (26 == count) {
// The magic values were chosen because they match a very common LCMS sRGB
// gamma table.
if (0 == read_big_endian_short((const uint8_t*) &table[0]) &&
3062 == read_big_endian_short((const uint8_t*) &table[6]) &&
12824 == read_big_endian_short((const uint8_t*) &table[12]) &&
31237 == read_big_endian_short((const uint8_t*) &table[18]) &&
65535 == read_big_endian_short((const uint8_t*) &table[25])) {
outData->fNamed = SkColorSpace::kSRGB_GammaNamed;
return SkGammas::Type::kNamed_Type;
}
}
if (4096 == count) {
// The magic values were chosen because they match Nikon, Epson, and
// LCMS sRGB gamma tables (all of which use different rounding rules).
if (0 == read_big_endian_short((const uint8_t*) &table[0]) &&
950 == read_big_endian_short((const uint8_t*) &table[515]) &&
3342 == read_big_endian_short((const uint8_t*) &table[1025]) &&
14079 == read_big_endian_short((const uint8_t*) &table[2051]) &&
65535 == read_big_endian_short((const uint8_t*) &table[4095])) {
outData->fNamed = SkColorSpace::kSRGB_GammaNamed;
return SkGammas::Type::kNamed_Type;
}
}
// Otherwise, we will represent gamma with a table.
outData->fTable.fSize = count;
return SkGammas::Type::kTable_Type;
}
case kTAG_ParaCurveType: {
enum ParaCurveType {
kExponential_ParaCurveType = 0,
kGAB_ParaCurveType = 1,
kGABC_ParaCurveType = 2,
kGABDE_ParaCurveType = 3,
kGABCDEF_ParaCurveType = 4,
};
// Determine the format of the parametric curve tag.
uint16_t format = read_big_endian_short(src + 8);
if (format > kGABCDEF_ParaCurveType) {
SkColorSpacePrintf("Unsupported gamma tag type %d\n", type);
return SkGammas::Type::kNone_Type;
}
if (kExponential_ParaCurveType == format) {
tagBytes = 12 + 4;
if (len < tagBytes) {
SkColorSpacePrintf("gamma tag is too small (%d bytes)", len);
return SkGammas::Type::kNone_Type;
}
// Y = X^g
float g = read_big_endian_16_dot_16(src + 12);
*outTagBytes = tagBytes;
return set_gamma_value(outData, g);
}
// Here's where the real parametric gammas start. There are many
// permutations of the same equations.
//
// Y = (aX + b)^g + c for X >= d
// Y = eX + f otherwise
//
// We will fill in with zeros as necessary to always match the above form.
if (len < 24) {
SkColorSpacePrintf("gamma tag is too small (%d bytes)", len);
return SkGammas::Type::kNone_Type;
}
float g = read_big_endian_16_dot_16(src + 12);
float a = read_big_endian_16_dot_16(src + 16);
float b = read_big_endian_16_dot_16(src + 20);
float c = 0.0f, d = 0.0f, e = 0.0f, f = 0.0f;
switch(format) {
case kGAB_ParaCurveType:
tagBytes = 12 + 12;
// Y = (aX + b)^g for X >= -b/a
// Y = 0 otherwise
d = -b / a;
break;
case kGABC_ParaCurveType:
tagBytes = 12 + 16;
if (len < tagBytes) {
SkColorSpacePrintf("gamma tag is too small (%d bytes)", len);
return SkGammas::Type::kNone_Type;
}
// Y = (aX + b)^g + c for X >= -b/a
// Y = c otherwise
c = read_big_endian_16_dot_16(src + 24);
d = -b / a;
f = c;
break;
case kGABDE_ParaCurveType:
tagBytes = 12 + 20;
if (len < tagBytes) {
SkColorSpacePrintf("gamma tag is too small (%d bytes)", len);
return SkGammas::Type::kNone_Type;
}
// Y = (aX + b)^g for X >= d
// Y = eX otherwise
d = read_big_endian_16_dot_16(src + 28);
// Not a bug! We define |e| to always be the coefficient on X in the
// second equation. The spec calls this |c| in this particular equation.
// We don't follow their convention because then |c| would have a
// different meaning in each of our cases.
e = read_big_endian_16_dot_16(src + 24);
break;
case kGABCDEF_ParaCurveType:
tagBytes = 12 + 28;
if (len < tagBytes) {
SkColorSpacePrintf("gamma tag is too small (%d bytes)", len);
return SkGammas::Type::kNone_Type;
}
// Y = (aX + b)^g + c for X >= d
// Y = eX + f otherwise
// NOTE: The ICC spec writes "cX" in place of "eX" but I think
// it's a typo.
c = read_big_endian_16_dot_16(src + 24);
d = read_big_endian_16_dot_16(src + 28);
e = read_big_endian_16_dot_16(src + 32);
f = read_big_endian_16_dot_16(src + 36);
break;
default:
SkASSERT(false);
return SkGammas::Type::kNone_Type;
}
// Recognize and simplify a very common parametric representation of sRGB gamma.
if (color_space_almost_equal(0.9479f, a) &&
color_space_almost_equal(0.0521f, b) &&
color_space_almost_equal(0.0000f, c) &&
color_space_almost_equal(0.0405f, d) &&
color_space_almost_equal(0.0774f, e) &&
color_space_almost_equal(0.0000f, f) &&
color_space_almost_equal(2.4000f, g)) {
outData->fNamed = SkColorSpace::kSRGB_GammaNamed;
return SkGammas::Type::kNamed_Type;
}
// Fail on invalid gammas.
if (SkScalarIsNaN(d)) {
return SkGammas::Type::kNone_Type;
}
if (d <= 0.0f) {
// Y = (aX + b)^g + c for always
if (0.0f == a || 0.0f == g) {
SkColorSpacePrintf("A or G is zero, constant gamma function "
"is nonsense");
return SkGammas::Type::kNone_Type;
}
}
if (d >= 1.0f) {
// Y = eX + f for always
if (0.0f == e) {
SkColorSpacePrintf("E is zero, constant gamma function is "
"nonsense");
return SkGammas::Type::kNone_Type;
}
}
if ((0.0f == a || 0.0f == g) && 0.0f == e) {
SkColorSpacePrintf("A or G, and E are zero, constant gamma function "
"is nonsense");
return SkGammas::Type::kNone_Type;
}
*outTagBytes = tagBytes;
outParams->fG = g;
outParams->fA = a;
outParams->fB = b;
outParams->fC = c;
outParams->fD = d;
outParams->fE = e;
outParams->fF = f;
return SkGammas::Type::kParam_Type;
}
default:
SkColorSpacePrintf("Unsupported gamma tag type %d\n", type);
return SkGammas::Type::kNone_Type;
}
}
/**
* Returns the additional size in bytes needed to store the gamma tag.
*/
static size_t gamma_alloc_size(SkGammas::Type type, const SkGammas::Data& data) {
switch (type) {
case SkGammas::Type::kNamed_Type:
case SkGammas::Type::kValue_Type:
return 0;
case SkGammas::Type::kTable_Type:
return sizeof(float) * data.fTable.fSize;
case SkGammas::Type::kParam_Type:
return sizeof(SkGammas::Params);
default:
SkASSERT(false);
return 0;
}
}
/**
* Sets invalid gamma to the default value.
*/
static void handle_invalid_gamma(SkGammas::Type* type, SkGammas::Data* data) {
if (SkGammas::Type::kNone_Type == *type) {
*type = SkGammas::Type::kNamed_Type;
data->fNamed = SkColorSpace::kSRGB_GammaNamed;
}
}
/**
* Finish loading the gammas, now that we have allocated memory for the SkGammas struct.
*
* There's nothing to do for the simple cases, but for table gammas we need to actually
* read the table into heap memory. And for parametric gammas, we need to copy over the
* parameter values.
*
* @param memory Pointer to start of the SkGammas memory block
* @param offset Bytes of memory (after the SkGammas struct) that are already in use.
* @param data In-out variable. Will fill in the offset to the table or parameters
* if necessary.
* @param params Parameters for gamma curve. Only initialized/used when we have a
* parametric gamma.
* @param src Pointer to start of the gamma tag.
*
* @return Additional bytes of memory that are being used by this gamma curve.
*/
static size_t load_gammas(void* memory, size_t offset, SkGammas::Type type,
SkGammas::Data* data, const SkGammas::Params& params,
const uint8_t* src) {
void* storage = SkTAddOffset<void>(memory, offset + sizeof(SkGammas));
switch (type) {
case SkGammas::Type::kNamed_Type:
case SkGammas::Type::kValue_Type:
// Nothing to do here.
return 0;
case SkGammas::Type::kTable_Type: {
data->fTable.fOffset = offset;
float* outTable = (float*) storage;
const uint16_t* inTable = (const uint16_t*) (src + 12);
for (int i = 0; i < data->fTable.fSize; i++) {
outTable[i] = read_big_endian_16_dot_16((const uint8_t*) &inTable[i]);
}
return sizeof(float) * data->fTable.fSize;
}
case SkGammas::Type::kParam_Type:
data->fTable.fOffset = offset;
memcpy(storage, &params, sizeof(SkGammas::Params));
return sizeof(SkGammas::Params);
default:
SkASSERT(false);
return 0;
}
}
static constexpr uint32_t kTAG_AtoBType = SkSetFourByteTag('m', 'A', 'B', ' ');
bool load_color_lut(SkColorLookUpTable* colorLUT, uint32_t inputChannels, uint32_t outputChannels,
const uint8_t* src, size_t len) {
static bool load_color_lut(SkColorLookUpTable* colorLUT, uint32_t inputChannels,
uint32_t outputChannels, const uint8_t* src, size_t len) {
// 16 bytes reserved for grid points, 2 for precision, 2 for padding.
// The color LUT data follows after this header.
static constexpr uint32_t kColorLUTHeaderSize = 20;
@ -587,7 +684,7 @@ bool load_color_lut(SkColorLookUpTable* colorLUT, uint32_t inputChannels, uint32
return true;
}
bool load_matrix(SkMatrix44* toXYZ, const uint8_t* src, size_t len) {
static bool load_matrix(SkMatrix44* toXYZ, const uint8_t* src, size_t len) {
if (len < 48) {
SkColorSpacePrintf("Matrix tag is too small (%d bytes).", len);
return false;
@ -616,8 +713,8 @@ bool load_matrix(SkMatrix44* toXYZ, const uint8_t* src, size_t len) {
return true;
}
bool load_a2b0(SkColorLookUpTable* colorLUT, SkGammaCurve* gammas, SkMatrix44* toXYZ,
const uint8_t* src, size_t len) {
static bool load_a2b0(SkColorLookUpTable* colorLUT, SkColorSpace::GammaNamed* gammaNamed,
sk_sp<SkGammas>* gammas, SkMatrix44* toXYZ, const uint8_t* src, size_t len) {
if (len < 32) {
SkColorSpacePrintf("A to B tag is too small (%d bytes).", len);
return false;
@ -665,11 +762,77 @@ bool load_a2b0(SkColorLookUpTable* colorLUT, SkGammaCurve* gammas, SkMatrix44* t
uint32_t offsetToMCurves = read_big_endian_int(src + 20);
if (0 != offsetToMCurves && offsetToMCurves < len) {
if (!load_gammas(gammas, outputChannels, src + offsetToMCurves, len - offsetToMCurves)) {
SkColorSpacePrintf("Failed to read M curves from A to B tag. Using linear gamma.\n");
gammas[0].fNamed = SkColorSpace::kLinear_GammaNamed;
gammas[1].fNamed = SkColorSpace::kLinear_GammaNamed;
gammas[2].fNamed = SkColorSpace::kLinear_GammaNamed;
const uint8_t* rTagPtr = src + offsetToMCurves;
size_t tagLen = len - offsetToMCurves;
SkGammas::Data rData;
SkGammas::Params rParams;
// On an invalid first gamma, tagBytes remains set as zero. This causes the two
// subsequent to be treated as identical (which is what we want).
size_t tagBytes = 0;
SkGammas::Type rType = parse_gamma(&rData, &rParams, &tagBytes, rTagPtr, tagLen);
handle_invalid_gamma(&rType, &rData);
size_t alignedTagBytes = SkAlign4(tagBytes);
if ((3 * alignedTagBytes <= tagLen) &&
!memcmp(rTagPtr, rTagPtr + 1 * alignedTagBytes, tagBytes) &&
!memcmp(rTagPtr, rTagPtr + 2 * alignedTagBytes, tagBytes))
{
if (SkGammas::Type::kNamed_Type == rType) {
*gammaNamed = rData.fNamed;
} else {
size_t allocSize = sizeof(SkGammas) + gamma_alloc_size(rType, rData);
void* memory = sk_malloc_throw(allocSize);
*gammas = sk_sp<SkGammas>(new (memory) SkGammas());
load_gammas(memory, 0, rType, &rData, rParams, rTagPtr);
(*gammas)->fRedType = rType;
(*gammas)->fGreenType = rType;
(*gammas)->fBlueType = rType;
(*gammas)->fRedData = rData;
(*gammas)->fGreenData = rData;
(*gammas)->fBlueData = rData;
}
} else {
const uint8_t* gTagPtr = rTagPtr + alignedTagBytes;
tagLen = tagLen > alignedTagBytes ? tagLen - alignedTagBytes : 0;
SkGammas::Data gData;
SkGammas::Params gParams;
tagBytes = 0;
SkGammas::Type gType = parse_gamma(&gData, &gParams, &tagBytes, gTagPtr,
tagLen);
handle_invalid_gamma(&gType, &gData);
alignedTagBytes = SkAlign4(tagBytes);
const uint8_t* bTagPtr = gTagPtr + alignedTagBytes;
tagLen = tagLen > alignedTagBytes ? tagLen - alignedTagBytes : 0;
SkGammas::Data bData;
SkGammas::Params bParams;
SkGammas::Type bType = parse_gamma(&bData, &bParams, &tagBytes, bTagPtr,
tagLen);
handle_invalid_gamma(&bType, &bData);
size_t allocSize = sizeof(SkGammas) + gamma_alloc_size(rType, rData)
+ gamma_alloc_size(gType, gData)
+ gamma_alloc_size(bType, bData);
void* memory = sk_malloc_throw(allocSize);
*gammas = sk_sp<SkGammas>(new (memory) SkGammas());
uint32_t offset = 0;
(*gammas)->fRedType = rType;
offset += load_gammas(memory, offset, rType, &rData, rParams, rTagPtr);
(*gammas)->fGreenType = gType;
offset += load_gammas(memory, offset, gType, &gData, gParams, gTagPtr);
(*gammas)->fBlueType = bType;
load_gammas(memory, offset, bType, &bData, bParams, bTagPtr);
(*gammas)->fRedData = rData;
(*gammas)->fGreenData = gData;
(*gammas)->fBlueData = bData;
}
}
@ -684,6 +847,22 @@ bool load_a2b0(SkColorLookUpTable* colorLUT, SkGammaCurve* gammas, SkMatrix44* t
return true;
}
static bool tag_equals(const ICCTag* a, const ICCTag* b, const uint8_t* base) {
if (!a || !b) {
return a == b;
}
if (a->fLength != b->fLength) {
return false;
}
if (a->fOffset == b->fOffset) {
return true;
}
return !memcmp(a->addr(base), b->addr(base), a->fLength);
}
sk_sp<SkColorSpace> SkColorSpace::NewICC(const void* input, size_t len) {
if (!input || len < kICCHeaderSize) {
return_null("Data is null or not large enough to contain an ICC profile");
@ -693,8 +872,8 @@ sk_sp<SkColorSpace> SkColorSpace::NewICC(const void* input, size_t len) {
void* memory = sk_malloc_throw(len);
memcpy(memory, input, len);
sk_sp<SkData> data = SkData::MakeFromMalloc(memory, len);
const void* base = data->data();
const uint8_t* ptr = (const uint8_t*) base;
const uint8_t* base = data->bytes();
const uint8_t* ptr = base;
// Read the ICC profile header and check to make sure that it is valid.
ICCProfileHeader header;
@ -740,44 +919,112 @@ sk_sp<SkColorSpace> SkColorSpace::NewICC(const void* input, size_t len) {
const ICCTag* b = ICCTag::Find(tags.get(), tagCount, kTAG_bXYZ);
if (r && g && b) {
float toXYZ[9];
if (!load_xyz(&toXYZ[0], r->addr((const uint8_t*) base), r->fLength) ||
!load_xyz(&toXYZ[3], g->addr((const uint8_t*) base), g->fLength) ||
!load_xyz(&toXYZ[6], b->addr((const uint8_t*) base), b->fLength))
if (!load_xyz(&toXYZ[0], r->addr(base), r->fLength) ||
!load_xyz(&toXYZ[3], g->addr(base), g->fLength) ||
!load_xyz(&toXYZ[6], b->addr(base), b->fLength))
{
return_null("Need valid rgb tags for XYZ space");
}
SkMatrix44 mat(SkMatrix44::kUninitialized_Constructor);
mat.set3x3RowMajorf(toXYZ);
// It is not uncommon to see missing or empty gamma tags. This indicates
// that we should use unit gamma.
SkGammaCurve curves[3];
r = ICCTag::Find(tags.get(), tagCount, kTAG_rTRC);
g = ICCTag::Find(tags.get(), tagCount, kTAG_gTRC);
b = ICCTag::Find(tags.get(), tagCount, kTAG_bTRC);
if (!r || !load_gammas(&curves[0], 1, r->addr((const uint8_t*) base), r->fLength))
{
SkColorSpacePrintf("Failed to read R gamma tag.\n");
curves[0].fNamed = SkColorSpace::kLinear_GammaNamed;
}
if (!g || !load_gammas(&curves[1], 1, g->addr((const uint8_t*) base), g->fLength))
{
SkColorSpacePrintf("Failed to read G gamma tag.\n");
curves[1].fNamed = SkColorSpace::kLinear_GammaNamed;
}
if (!b || !load_gammas(&curves[2], 1, b->addr((const uint8_t*) base), b->fLength))
{
SkColorSpacePrintf("Failed to read B gamma tag.\n");
curves[2].fNamed = SkColorSpace::kLinear_GammaNamed;
// If some, but not all, of the gamma tags are missing, assume that all
// gammas are meant to be the same. This behavior is an arbitrary guess,
// but it simplifies the code below.
if ((!r || !g || !b) && (r || g || b)) {
if (!r) {
r = g ? g : b;
}
if (!g) {
g = r ? r : b;
}
if (!b) {
b = r ? r : g;
}
}
GammaNamed gammaNamed = kNonStandard_GammaNamed;
sk_sp<SkGammas> gammas = nullptr;
size_t tagBytes;
if (r && g && b) {
if (tag_equals(r, g, base) && tag_equals(g, b, base)) {
SkGammas::Data data;
SkGammas::Params params;
SkGammas::Type Type =
parse_gamma(&data, &params, &tagBytes, r->addr(base), r->fLength);
handle_invalid_gamma(&Type, &data);
if (SkGammas::Type::kNamed_Type == Type) {
gammaNamed = data.fNamed;
} else {
size_t allocSize = sizeof(SkGammas) + gamma_alloc_size(Type, data);
void* memory = sk_malloc_throw(allocSize);
gammas = sk_sp<SkGammas>(new (memory) SkGammas());
load_gammas(memory, 0, Type, &data, params, r->addr(base));
gammas->fRedType = Type;
gammas->fGreenType = Type;
gammas->fBlueType = Type;
gammas->fRedData = data;
gammas->fGreenData = data;
gammas->fBlueData = data;
}
} else {
SkGammas::Data rData;
SkGammas::Params rParams;
SkGammas::Type rType =
parse_gamma(&rData, &rParams, &tagBytes, r->addr(base), r->fLength);
handle_invalid_gamma(&rType, &rData);
SkGammas::Data gData;
SkGammas::Params gParams;
SkGammas::Type gType =
parse_gamma(&gData, &gParams, &tagBytes, g->addr(base), g->fLength);
handle_invalid_gamma(&gType, &gData);
SkGammas::Data bData;
SkGammas::Params bParams;
SkGammas::Type bType =
parse_gamma(&bData, &bParams, &tagBytes, b->addr(base), b->fLength);
handle_invalid_gamma(&bType, &bData);
size_t allocSize = sizeof(SkGammas) + gamma_alloc_size(rType, rData)
+ gamma_alloc_size(gType, gData)
+ gamma_alloc_size(bType, bData);
void* memory = sk_malloc_throw(allocSize);
gammas = sk_sp<SkGammas>(new (memory) SkGammas());
uint32_t offset = 0;
gammas->fRedType = rType;
offset += load_gammas(memory, offset, rType, &rData, rParams,
r->addr(base));
gammas->fGreenType = gType;
offset += load_gammas(memory, offset, gType, &gData, gParams,
g->addr(base));
gammas->fBlueType = bType;
load_gammas(memory, offset, bType, &bData, bParams, b->addr(base));
gammas->fRedData = rData;
gammas->fGreenData = gData;
gammas->fBlueData = bData;
}
} else {
gammaNamed = kLinear_GammaNamed;
}
GammaNamed gammaNamed = SkGammas::Named(curves);
if (kNonStandard_GammaNamed == gammaNamed) {
sk_sp<SkGammas> gammas = sk_make_sp<SkGammas>(std::move(curves[0]),
std::move(curves[1]),
std::move(curves[2]));
return sk_sp<SkColorSpace>(new SkColorSpace_Base(nullptr, std::move(gammas),
mat, std::move(data)));
return sk_sp<SkColorSpace>(new SkColorSpace_Base(nullptr, gammaNamed,
std::move(gammas), mat,
std::move(data)));
} else {
return SkColorSpace_Base::NewRGB(gammaNamed, mat);
}
@ -786,24 +1033,20 @@ sk_sp<SkColorSpace> SkColorSpace::NewICC(const void* input, size_t len) {
// Recognize color profile specified by A2B0 tag.
const ICCTag* a2b0 = ICCTag::Find(tags.get(), tagCount, kTAG_A2B0);
if (a2b0) {
GammaNamed gammaNamed = kNonStandard_GammaNamed;
sk_sp<SkGammas> gammas = nullptr;
sk_sp<SkColorLookUpTable> colorLUT = sk_make_sp<SkColorLookUpTable>();
SkGammaCurve curves[3];
SkMatrix44 toXYZ(SkMatrix44::kUninitialized_Constructor);
if (!load_a2b0(colorLUT.get(), curves, &toXYZ, a2b0->addr((const uint8_t*) base),
if (!load_a2b0(colorLUT.get(), &gammaNamed, &gammas, &toXYZ, a2b0->addr(base),
a2b0->fLength)) {
return_null("Failed to parse A2B0 tag");
}
GammaNamed gammaNamed = SkGammas::Named(curves);
colorLUT = colorLUT->fTable ? colorLUT : nullptr;
if (colorLUT || kNonStandard_GammaNamed == gammaNamed) {
sk_sp<SkGammas> gammas = sk_make_sp<SkGammas>(std::move(curves[0]),
std::move(curves[1]),
std::move(curves[2]));
return sk_sp<SkColorSpace>(new SkColorSpace_Base(std::move(colorLUT),
std::move(gammas), toXYZ,
std::move(data)));
gammaNamed, std::move(gammas),
toXYZ, std::move(data)));
} else {
return SkColorSpace_Base::NewRGB(gammaNamed, toXYZ);
}
@ -945,23 +1188,6 @@ static void write_trc_tag(uint32_t* ptr, float value) {
ptr16[1] = 0;
}
static float get_gamma_value(const SkGammaCurve* curve) {
switch (curve->fNamed) {
case SkColorSpace::kSRGB_GammaNamed:
// FIXME (msarett):
// kSRGB cannot be represented by a value. Here we fall through to 2.2f,
// which is a close guess. To be more accurate, we need to represent sRGB
// gamma with a parametric curve.
case SkColorSpace::k2Dot2Curve_GammaNamed:
return 2.2f;
case SkColorSpace::kLinear_GammaNamed:
return 1.0f;
default:
SkASSERT(curve->isValue());
return curve->fValue;
}
}
sk_sp<SkData> SkColorSpace_Base::writeToICC() const {
// Return if this object was created from a profile, or if we have already serialized
// the profile.
@ -1005,11 +1231,13 @@ sk_sp<SkData> SkColorSpace_Base::writeToICC() const {
// Write TRC tags
GammaNamed gammaNamed = this->gammaNamed();
if (kNonStandard_GammaNamed == gammaNamed) {
write_trc_tag((uint32_t*) ptr, get_gamma_value(&as_CSB(this)->fGammas->fRed));
// FIXME (msarett):
// Write the correct gamma representation rather than 2.2f.
write_trc_tag((uint32_t*) ptr, 2.2f);
ptr += SkAlign4(kTAG_TRC_Bytes);
write_trc_tag((uint32_t*) ptr, get_gamma_value(&as_CSB(this)->fGammas->fGreen));
write_trc_tag((uint32_t*) ptr, 2.2f);
ptr += SkAlign4(kTAG_TRC_Bytes);
write_trc_tag((uint32_t*) ptr, get_gamma_value(&as_CSB(this)->fGammas->fBlue));
write_trc_tag((uint32_t*) ptr, 2.2f);
ptr += SkAlign4(kTAG_TRC_Bytes);
} else {
switch (gammaNamed) {

112
tests/ColorSpaceXformTest.cpp
View File

@ -17,7 +17,8 @@ class ColorSpaceXformTest {
public:
static std::unique_ptr<SkColorSpaceXform> CreateIdentityXform(const sk_sp<SkGammas>& gammas) {
// Logically we can pass any matrix here. For simplicty, pass I(), i.e. D50 XYZ gamut.
sk_sp<SkColorSpace> space(new SkColorSpace_Base(nullptr, gammas, SkMatrix::I(), nullptr));
sk_sp<SkColorSpace> space(new SkColorSpace_Base(
nullptr, SkColorSpace::kNonStandard_GammaNamed, gammas, SkMatrix::I(), nullptr));
return SkColorSpaceXform::New(space, space);
}
};
@ -54,53 +55,102 @@ static void test_identity_xform(skiatest::Reporter* r, const sk_sp<SkGammas>& ga
DEF_TEST(ColorSpaceXform_TableGamma, r) {
// Lookup-table based gamma curves
SkGammaCurve red, green, blue;
constexpr size_t tableSize = 10;
red.fTable = std::unique_ptr<float[]>(new float[tableSize]);
green.fTable = std::unique_ptr<float[]>(new float[tableSize]);
blue.fTable = std::unique_ptr<float[]>(new float[tableSize]);
red.fTableSize = green.fTableSize = blue.fTableSize = 10;
red.fTable[0] = green.fTable[0] = blue.fTable[0] = 0.00f;
red.fTable[1] = green.fTable[1] = blue.fTable[1] = 0.05f;
red.fTable[2] = green.fTable[2] = blue.fTable[2] = 0.10f;
red.fTable[3] = green.fTable[3] = blue.fTable[3] = 0.15f;
red.fTable[4] = green.fTable[4] = blue.fTable[4] = 0.25f;
red.fTable[5] = green.fTable[5] = blue.fTable[5] = 0.35f;
red.fTable[6] = green.fTable[6] = blue.fTable[6] = 0.45f;
red.fTable[7] = green.fTable[7] = blue.fTable[7] = 0.60f;
red.fTable[8] = green.fTable[8] = blue.fTable[8] = 0.75f;
red.fTable[9] = green.fTable[9] = blue.fTable[9] = 1.00f;
sk_sp<SkGammas> gammas =
sk_make_sp<SkGammas>(std::move(red), std::move(green), std::move(blue));
void* memory = sk_malloc_throw(sizeof(SkGammas) + sizeof(float) * tableSize);
sk_sp<SkGammas> gammas = sk_sp<SkGammas>(new (memory) SkGammas());
gammas->fRedType = gammas->fGreenType = gammas->fBlueType =
SkGammas::Type::kTable_Type;
gammas->fRedData.fTable.fSize = gammas->fGreenData.fTable.fSize =
gammas->fBlueData.fTable.fSize = tableSize;
gammas->fRedData.fTable.fOffset = gammas->fGreenData.fTable.fOffset =
gammas->fBlueData.fTable.fOffset = 0;
float* table = SkTAddOffset<float>(memory, sizeof(SkGammas));
table[0] = 0.00f;
table[1] = 0.05f;
table[2] = 0.10f;
table[3] = 0.15f;
table[4] = 0.25f;
table[5] = 0.35f;
table[6] = 0.45f;
table[7] = 0.60f;
table[8] = 0.75f;
table[9] = 1.00f;
test_identity_xform(r, gammas);
}
DEF_TEST(ColorSpaceXform_ParametricGamma, r) {
// Parametric gamma curves
SkGammaCurve red, green, blue;
void* memory = sk_malloc_throw(sizeof(SkGammas) + sizeof(SkGammas::Params));
sk_sp<SkGammas> gammas = sk_sp<SkGammas>(new (memory) SkGammas());
gammas->fRedType = gammas->fGreenType = gammas->fBlueType =
SkGammas::Type::kParam_Type;
gammas->fRedData.fParamOffset = gammas->fGreenData.fParamOffset =
gammas->fBlueData.fParamOffset = 0;
SkGammas::Params* params = SkTAddOffset<SkGammas::Params>(memory, sizeof(SkGammas));
// Interval, switch xforms at 0.0031308f
red.fD = green.fD = blue.fD = 0.04045f;
params->fD = 0.04045f;
// First equation:
red.fE = green.fE = blue.fE = 1.0f / 12.92f;
params->fE = 1.0f / 12.92f;
params->fF = 0.0f;
// Second equation:
// Note that the function is continuous (it's actually sRGB).
red.fA = green.fA = blue.fA = 1.0f / 1.055f;
red.fB = green.fB = blue.fB = 0.055f / 1.055f;
red.fC = green.fC = blue.fC = 0.0f;
red.fG = green.fG = blue.fG = 2.4f;
sk_sp<SkGammas> gammas =
sk_make_sp<SkGammas>(std::move(red), std::move(green), std::move(blue));
params->fA = 1.0f / 1.055f;
params->fB = 0.055f / 1.055f;
params->fC = 0.0f;
params->fG = 2.4f;
test_identity_xform(r, gammas);
}
DEF_TEST(ColorSpaceXform_ExponentialGamma, r) {
// Exponential gamma curves
SkGammaCurve red, green, blue;
red.fValue = green.fValue = blue.fValue = 1.4f;
sk_sp<SkGammas> gammas =
sk_make_sp<SkGammas>(std::move(red), std::move(green), std::move(blue));
sk_sp<SkGammas> gammas = sk_sp<SkGammas>(new SkGammas());
gammas->fRedType = gammas->fGreenType = gammas->fBlueType =
SkGammas::Type::kValue_Type;
gammas->fRedData.fValue = gammas->fGreenData.fValue = gammas->fBlueData.fValue = 1.4f;
test_identity_xform(r, gammas);
}
DEF_TEST(ColorSpaceXform_NonMatchingGamma, r) {
constexpr size_t tableSize = 10;
void* memory = sk_malloc_throw(sizeof(SkGammas) + sizeof(float) * tableSize +
sizeof(SkGammas::Params));
sk_sp<SkGammas> gammas = sk_sp<SkGammas>(new (memory) SkGammas());
float* table = SkTAddOffset<float>(memory, sizeof(SkGammas));
table[0] = 0.00f;
table[1] = 0.15f;
table[2] = 0.20f;
table[3] = 0.25f;
table[4] = 0.35f;
table[5] = 0.45f;
table[6] = 0.55f;
table[7] = 0.70f;
table[8] = 0.85f;
table[9] = 1.00f;
SkGammas::Params* params = SkTAddOffset<SkGammas::Params>(memory, sizeof(SkGammas) +
sizeof(float) * tableSize);
params->fA = 1.0f / 1.055f;
params->fB = 0.055f / 1.055f;
params->fC = 0.0f;
params->fD = 0.04045f;
params->fE = 1.0f / 12.92f;
params->fF = 0.0f;
params->fG = 2.4f;
gammas->fRedType = SkGammas::Type::kValue_Type;
gammas->fRedData.fValue = 1.2f;
gammas->fGreenType = SkGammas::Type::kTable_Type;
gammas->fGreenData.fTable.fSize = tableSize;
gammas->fGreenData.fTable.fOffset = 0;
gammas->fBlueType = SkGammas::Type::kParam_Type;
gammas->fBlueData.fParamOffset = sizeof(float) * tableSize;
test_identity_xform(r, gammas);
}