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/*
* 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 "SkAtomics.h"
#include "SkColorSpace.h"
static inline bool SkFloatIsFinite(float x) { return 0 == x * 0; }
//
// SkFloat3x3
//
// In memory order, values are a, b, c, d, e, f, g, h, i
//
// When applied to a color component vector (e.g. [ r, r, r ] or [ g, g, g ] we do
//
// [ r r r ] * [ a b c ] + [ g g g ] * [ d e f ] + [ b b b ] * [ g h i ]
//
// Thus in our point-on-the-right notation, the matrix looks like
//
// [ a d g ] [ r ]
// [ b e h ] * [ g ]
// [ c f i ] [ b ]
//
static SkFloat3x3 concat(const SkFloat3x3& left, const SkFloat3x3& rite) {
SkFloat3x3 result;
for (int row = 0; row < 3; ++row) {
for (int col = 0; col < 3; ++col) {
double tmp = 0;
for (int i = 0; i < 3; ++i) {
tmp += (double)left.fMat[row + i * 3] * rite.fMat[i + col * 3];
}
result.fMat[row + col * 3] = (double)tmp;
}
}
return result;
}
static double det(const SkFloat3x3& m) {
return (double)m.fMat[0] * m.fMat[4] * m.fMat[8] +
(double)m.fMat[3] * m.fMat[7] * m.fMat[2] +
(double)m.fMat[6] * m.fMat[1] * m.fMat[5] -
(double)m.fMat[0] * m.fMat[7] * m.fMat[5] -
(double)m.fMat[3] * m.fMat[1] * m.fMat[8] -
(double)m.fMat[6] * m.fMat[4] * m.fMat[2];
}
static double det2x2(const SkFloat3x3& m, int a, int b, int c, int d) {
return (double)m.fMat[a] * m.fMat[b] - (double)m.fMat[c] * m.fMat[d];
}
static SkFloat3x3 invert(const SkFloat3x3& m) {
double d = det(m);
SkASSERT(SkFloatIsFinite((float)d));
double scale = 1 / d;
SkASSERT(SkFloatIsFinite((float)scale));
return {{
(float)(scale * det2x2(m, 4, 8, 5, 7)),
(float)(scale * det2x2(m, 7, 2, 8, 1)),
(float)(scale * det2x2(m, 1, 5, 2, 4)),
(float)(scale * det2x2(m, 6, 5, 8, 3)),
(float)(scale * det2x2(m, 0, 8, 2, 6)),
(float)(scale * det2x2(m, 3, 2, 5, 0)),
(float)(scale * det2x2(m, 3, 7, 4, 6)),
(float)(scale * det2x2(m, 6, 1, 7, 0)),
(float)(scale * det2x2(m, 0, 4, 1, 3)),
}};
}
void SkFloat3::dump() const {
SkDebugf("[%7.4f %7.4f %7.4f]\n", fVec[0], fVec[1], fVec[2]);
}
void SkFloat3x3::dump() const {
SkDebugf("[%7.4f %7.4f %7.4f] [%7.4f %7.4f %7.4f] [%7.4f %7.4f %7.4f]\n",
fMat[0], fMat[1], fMat[2],
fMat[3], fMat[4], fMat[5],
fMat[6], fMat[7], fMat[8]);
}
//////////////////////////////////////////////////////////////////////////////////////////////////
static int32_t gUniqueColorSpaceID;
SkColorSpace::SkColorSpace(const SkFloat3x3& toXYZD50, const SkFloat3& gamma, Named named)
: fToXYZD50(toXYZD50)
, fGamma(gamma)
, fUniqueID(sk_atomic_inc(&gUniqueColorSpaceID))
, fNamed(named)
{
for (int i = 0; i < 3; ++i) {
SkASSERT(SkFloatIsFinite(gamma.fVec[i]));
for (int j = 0; j < 3; ++j) {
SkASSERT(SkFloatIsFinite(toXYZD50.fMat[3*i + j]));
}
}
}
SkColorSpace* SkColorSpace::NewRGB(const SkFloat3x3& toXYZD50, const SkFloat3& gamma) {
for (int i = 0; i < 3; ++i) {
if (!SkFloatIsFinite(gamma.fVec[i]) || gamma.fVec[i] < 0) {
return nullptr;
}
for (int j = 0; j < 3; ++j) {
if (!SkFloatIsFinite(toXYZD50.fMat[3*i + j])) {
return nullptr;
}
}
}
// check the matrix for invertibility
float d = det(toXYZD50);
if (!SkFloatIsFinite(d) || !SkFloatIsFinite(1 / d)) {
return nullptr;
}
return new SkColorSpace(toXYZD50, gamma, kUnknown_Named);
}
void SkColorSpace::dump() const {
fToXYZD50.dump();
fGamma.dump();
}
//////////////////////////////////////////////////////////////////////////////////////////////////
const SkFloat3 gDevice_gamma {{ 0, 0, 0 }};
const SkFloat3x3 gDevice_toXYZD50 {{
1, 0, 0,
0, 1, 0,
0, 0, 1
}};
const SkFloat3 gSRGB_gamma {{ 2.2f, 2.2f, 2.2f }};
const SkFloat3x3 gSRGB_toXYZD50 {{
0.4358f, 0.2224f, 0.0139f, // * R
0.3853f, 0.7170f, 0.0971f, // * G
0.1430f, 0.0606f, 0.7139f, // * B
}};
SkColorSpace* SkColorSpace::NewNamed(Named named) {
switch (named) {
case kDevice_Named:
return new SkColorSpace(gDevice_toXYZD50, gDevice_gamma, kDevice_Named);
case kSRGB_Named:
return new SkColorSpace(gSRGB_toXYZD50, gSRGB_gamma, kSRGB_Named);
default:
break;
}
return nullptr;
}
///////////////////////////////////////////////////////////////////////////////////////////////////
SkColorSpace::Result SkColorSpace::Concat(const SkColorSpace* src, const SkColorSpace* dst,
SkFloat3x3* result) {
if (!src || !dst || (src->named() == kDevice_Named) || (src->named() == dst->named())) {
if (result) {
*result = {{ 1, 0, 0, 0, 1, 0, 0, 0, 1 }};
}
return kIdentity_Result;
}
if (result) {
*result = concat(src->fToXYZD50, invert(dst->fToXYZD50));
}
return kNormal_Result;
}
#include "SkColor.h"
#include "SkNx.h"
#include "SkPM4f.h"
void SkApply3x3ToPM4f(const SkFloat3x3& m, const SkPM4f src[], SkPM4f dst[], int count) {
SkASSERT(1 == SkPM4f::G);
SkASSERT(3 == SkPM4f::A);
Sk4f cr, cg, cb;
cg = Sk4f::Load(m.fMat + 3);
if (0 == SkPM4f::R) {
SkASSERT(2 == SkPM4f::B);
cr = Sk4f::Load(m.fMat + 0);
cb = Sk4f(m.fMat[6], m.fMat[7], m.fMat[8], 0);
} else {
SkASSERT(0 == SkPM4f::B);
SkASSERT(2 == SkPM4f::R);
cb = Sk4f::Load(m.fMat + 0);
cr = Sk4f(m.fMat[6], m.fMat[7], m.fMat[8], 0);
}
cr = cr * Sk4f(1, 1, 1, 0);
cg = cg * Sk4f(1, 1, 1, 0);
cb = cb * Sk4f(1, 1, 1, 0);
for (int i = 0; i < count; ++i) {
Sk4f r = Sk4f(src[i].fVec[SkPM4f::R]);
Sk4f g = Sk4f(src[i].fVec[SkPM4f::G]);
Sk4f b = Sk4f(src[i].fVec[SkPM4f::B]);
Sk4f a = Sk4f(0, 0, 0, src[i].fVec[SkPM4f::A]);
(cr * r + cg * g + cb * b + a).store(&dst[i]);
}
}
///////////////////////////////////////////////////////////////////////////////////////////////////
void SkColorSpace::Test() {
SkFloat3x3 mat {{ 2, 0, 0, 0, 3, 0, 0, 0, 4 }};
SkFloat3x3 inv = invert(mat);
mat.dump();
inv.dump();
concat(mat, inv).dump();
concat(inv, mat).dump();
SkDebugf("\n");
mat = gSRGB_toXYZD50;
inv = invert(mat);
mat.dump();
inv.dump();
concat(mat, inv).dump();
concat(inv, mat).dump();
SkDebugf("\n");
SkAutoTUnref<SkColorSpace> cs0(SkColorSpace::NewNamed(SkColorSpace::kSRGB_Named));
SkAutoTUnref<SkColorSpace> cs1(SkColorSpace::NewNamed(SkColorSpace::kSRGB_Named));
cs0->dump();
cs1->dump();
SkFloat3x3 xform;
(void)SkColorSpace::Concat(cs0, cs1, &xform);
xform.dump();
SkDebugf("\n");
}
// D65 white point of Rec. 709 [8] are:
//
// D65 white-point in unit luminance XYZ = 0.9505, 1.0000, 1.0890
//
// R G B white
// x 0.640 0.300 0.150 0.3127
// y 0.330 0.600 0.060 0.3290
// z 0.030 0.100 0.790 0.3582
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