sk_sp<SkColorSpace> SkColorSpace::NewRGB(float gammaVals[3], const SkMatrix44& toXYZD50) {
sk_sp<SkGammas> gammas = nullptr;
// Check if we really have sRGB or Adobe RGB
if (color_space_almost_equal(2.2f, gammaVals[0]) &&
color_space_almost_equal(2.2f, gammaVals[1]) &&
color_space_almost_equal(2.2f, gammaVals[2]))
{
gStandardGammasOnce([] {
gStandardGammas = new SkGammas(2.2f, 2.2f, 2.2f);
});
gammas = sk_ref_sp(gStandardGammas);
if (xyz_almost_equal(toXYZD50, gSRGB_toXYZD50)) {
return SkColorSpace::NewNamed(kSRGB_Named);
} else if (xyz_almost_equal(toXYZD50, gAdobeRGB_toXYZD50)) {
return SkColorSpace::NewNamed(kAdobeRGB_Named);
}
}
if (!gammas) {
gammas = sk_sp<SkGammas>(new SkGammas(gammaVals[0], gammaVals[1], gammaVals[2]));
}
return sk_sp<SkColorSpace>(new SkColorSpace(gammas, toXYZD50, kUnknown_Named));
}
bool valid() const {
return_if_false(fSize >= kICCHeaderSize, "Size is too small");
uint8_t majorVersion = fVersion >> 24;
return_if_false(majorVersion <= 4, "Unsupported version");
// These are the three basic classes of profiles that we might expect to see embedded
// in images. Four additional classes exist, but they generally are used as a convenient
// way for CMMs to store calculated transforms.
const uint32_t kDisplay_Profile = SkSetFourByteTag('m', 'n', 't', 'r');
const uint32_t kInput_Profile = SkSetFourByteTag('s', 'c', 'n', 'r');
const uint32_t kOutput_Profile = SkSetFourByteTag('p', 'r', 't', 'r');
return_if_false(fProfileClass == kDisplay_Profile ||
fProfileClass == kInput_Profile ||
fProfileClass == kOutput_Profile,
"Unsupported profile");
// TODO (msarett):
// All the profiles we've tested so far use RGB as the input color space.
return_if_false(fInputColorSpace == kRGB_ColorSpace, "Unsupported color space");
// TODO (msarett):
// All the profiles we've tested so far use XYZ as the profile connection space.
const uint32_t kXYZ_PCSSpace = SkSetFourByteTag('X', 'Y', 'Z', ' ');
return_if_false(fPCS == kXYZ_PCSSpace, "Unsupported PCS space");
return_if_false(fSignature == SkSetFourByteTag('a', 'c', 's', 'p'), "Bad signature");
// TODO (msarett):
// Should we treat different rendering intents differently?
// Valid rendering intents include kPerceptual (0), kRelative (1),
// kSaturation (2), and kAbsolute (3).
return_if_false(fRenderingIntent <= 3, "Bad rendering intent");
return_if_false(color_space_almost_equal(SkFixedToFloat(fIlluminantXYZ[0]), 0.96420f) &&
color_space_almost_equal(SkFixedToFloat(fIlluminantXYZ[1]), 1.00000f) &&
color_space_almost_equal(SkFixedToFloat(fIlluminantXYZ[2]), 0.82491f),
"Illuminant must be D50");
return_if_false(fTagCount <= 100, "Too many tags");
return true;
}
static bool xyz_almost_equal(const skcms_Matrix3x3& mA, const skcms_Matrix3x3& mB) {
for (int r = 0; r < 3; ++r) {
for (int c = 0; c < 3; ++c) {
if (!color_space_almost_equal(mA.vals[r][c], mB.vals[r][c])) {
return false;
}
}
}
return true;
}
/**
* Checks if our toXYZ matrix is a close match to a known color gamut.
*
* @param toXYZD50 transformation matrix deduced from profile data
* @param standard 3x3 canonical transformation matrix
*/
static bool xyz_almost_equal(const SkMatrix44& toXYZD50, const float* standard) {
return color_space_almost_equal(toXYZD50.getFloat(0, 0), standard[0]) &&
color_space_almost_equal(toXYZD50.getFloat(0, 1), standard[1]) &&
color_space_almost_equal(toXYZD50.getFloat(0, 2), standard[2]) &&
color_space_almost_equal(toXYZD50.getFloat(1, 0), standard[3]) &&
color_space_almost_equal(toXYZD50.getFloat(1, 1), standard[4]) &&
color_space_almost_equal(toXYZD50.getFloat(1, 2), standard[5]) &&
color_space_almost_equal(toXYZD50.getFloat(2, 0), standard[6]) &&
color_space_almost_equal(toXYZD50.getFloat(2, 1), standard[7]) &&
color_space_almost_equal(toXYZD50.getFloat(2, 2), standard[8]) &&
color_space_almost_equal(toXYZD50.getFloat(0, 3), 0.0f) &&
color_space_almost_equal(toXYZD50.getFloat(1, 3), 0.0f) &&
color_space_almost_equal(toXYZD50.getFloat(2, 3), 0.0f) &&
color_space_almost_equal(toXYZD50.getFloat(3, 0), 0.0f) &&
color_space_almost_equal(toXYZD50.getFloat(3, 1), 0.0f) &&
color_space_almost_equal(toXYZD50.getFloat(3, 2), 0.0f) &&
color_space_almost_equal(toXYZD50.getFloat(3, 3), 1.0f);
}
