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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.
*/
#ifndef SkPM4fPriv_DEFINED
#define SkPM4fPriv_DEFINED
#include "SkColorPriv.h"
#include "SkColorSpace.h"
#include "SkColorSpace_Base.h"
#include "SkArenaAlloc.h"
#include "SkPM4f.h"
#include "SkRasterPipeline.h"
#include "SkSRGB.h"
static inline Sk4f set_alpha(const Sk4f& px, float alpha) {
return { px[0], px[1], px[2], alpha };
}
static inline float get_alpha(const Sk4f& px) {
return px[3];
}
static inline Sk4f Sk4f_fromL32(uint32_t px) {
return SkNx_cast<float>(Sk4b::Load(&px)) * (1/255.0f);
}
static inline Sk4f Sk4f_fromS32(uint32_t px) {
return { sk_linear_from_srgb[(px >> 0) & 0xff],
sk_linear_from_srgb[(px >> 8) & 0xff],
sk_linear_from_srgb[(px >> 16) & 0xff],
(1/255.0f) * (px >> 24) };
}
static inline uint32_t Sk4f_toL32(const Sk4f& px) {
uint32_t l32;
SkNx_cast<uint8_t>(Sk4f_round(px * 255.0f)).store(&l32);
return l32;
}
static inline uint32_t Sk4f_toS32(const Sk4f& px) {
Sk4i rgb = sk_linear_to_srgb(px),
srgb = { rgb[0], rgb[1], rgb[2], (int)(255.0f * px[3] + 0.5f) };
uint32_t s32;
SkNx_cast<uint8_t>(srgb).store(&s32);
return s32;
}
// SkColor handling:
// SkColor has an ordering of (b, g, r, a) if cast to an Sk4f, so the code swizzles r and b to
// produce the needed (r, g, b, a) ordering.
static inline Sk4f Sk4f_from_SkColor(SkColor color) {
return swizzle_rb(Sk4f_fromS32(color));
}
static inline void assert_unit(float x) {
SkASSERT(0 <= x && x <= 1);
}
static inline float exact_srgb_to_linear(float srgb) {
assert_unit(srgb);
float linear;
if (srgb <= 0.04045) {
linear = srgb / 12.92f;
} else {
linear = powf((srgb + 0.055f) / 1.055f, 2.4f);
}
assert_unit(linear);
return linear;
}
static inline void analyze_3x4_matrix(const float matrix[12],
bool* can_underflow, bool* can_overflow) {
// | 0 3 6 9 | |r| |x|
// | 1 4 7 10 | x |g| = |y|
// | 2 5 8 11 | |b| |z|
// |1|
// We'll find min/max bounds on each of x,y,z assuming r,g,b are all in [0,1].
// If any can be <0, we'll set can_underflow; if any can be >1, can_overflow.
bool underflow = false,
overflow = false;
for (int i = 0; i < 3; i++) {
SkScalar min = matrix[i+9],
max = matrix[i+9];
(matrix[i+0] < 0 ? min : max) += matrix[i+0];
(matrix[i+3] < 0 ? min : max) += matrix[i+3];
(matrix[i+6] < 0 ? min : max) += matrix[i+6];
underflow = underflow || min < 0;
overflow = overflow || max > 1;
}
*can_underflow = underflow;
*can_overflow = overflow;
}
// N.B. scratch_matrix_3x4 must live at least as long as p.
static inline void append_gamut_transform(SkRasterPipeline* p, float scratch_matrix_3x4[12],
SkColorSpace* src, SkColorSpace* dst) {
if (src == dst) { return; } // That was easy.
if (!dst) { return; } // Legacy modes intentionally ignore color gamut.
if (!src) { return; } // A null src color space means linear gamma, dst gamut.
auto toXYZ = as_CSB(src)-> toXYZD50(),
fromXYZ = as_CSB(dst)->fromXYZD50();
if (!toXYZ || !fromXYZ) {
SkASSERT(false); // We really don't want to get here with a weird colorspace.
return;
}
// Slightly more sophisticated version of if (src == dst)
if (as_CSB(src)->toXYZD50Hash() == as_CSB(dst)->toXYZD50Hash()) {
return;
}
SkMatrix44 m44(*fromXYZ, *toXYZ);
// Convert from 4x4 to (column-major) 3x4.
auto ptr = scratch_matrix_3x4;
*ptr++ = m44.get(0,0); *ptr++ = m44.get(1,0); *ptr++ = m44.get(2,0);
*ptr++ = m44.get(0,1); *ptr++ = m44.get(1,1); *ptr++ = m44.get(2,1);
*ptr++ = m44.get(0,2); *ptr++ = m44.get(1,2); *ptr++ = m44.get(2,2);
*ptr++ = m44.get(0,3); *ptr++ = m44.get(1,3); *ptr++ = m44.get(2,3);
bool needs_clamp_0, needs_clamp_a;
analyze_3x4_matrix(scratch_matrix_3x4, &needs_clamp_0, &needs_clamp_a);
p->append(SkRasterPipeline::matrix_3x4, scratch_matrix_3x4);
if (needs_clamp_0) { p->append(SkRasterPipeline::clamp_0); }
if (needs_clamp_a) { p->append(SkRasterPipeline::clamp_a); }
}
static inline void append_gamut_transform(SkRasterPipeline* p, SkArenaAlloc* scratch,
SkColorSpace* src, SkColorSpace* dst) {
append_gamut_transform(p, scratch->makeArrayDefault<float>(12), src, dst);
}
static inline SkColor4f to_colorspace(const SkColor4f& c, SkColorSpace* src, SkColorSpace* dst) {
SkColor4f color4f = c;
if (src && dst) {
void* color4f_ptr = &color4f;
float scratch_matrix_3x4[12];
SkRasterPipeline p;
p.append(SkRasterPipeline::constant_color, color4f_ptr);
append_gamut_transform(&p, scratch_matrix_3x4, src, dst);
p.append(SkRasterPipeline::store_f32, &color4f_ptr);
p.run(0,1);
}
return color4f;
}
static inline SkColor4f SkColor4f_from_SkColor(SkColor color, SkColorSpace* dst) {
SkColor4f color4f;
if (dst) {
// sRGB gamma, sRGB gamut.
color4f = to_colorspace(SkColor4f::FromColor(color),
SkColorSpace::MakeSRGB().get(), dst);
} else {
// Linear gamma, dst gamut.
swizzle_rb(SkNx_cast<float>(Sk4b::Load(&color)) * (1/255.0f)).store(&color4f);
}
return color4f;
}
static inline SkPM4f SkPM4f_from_SkColor(SkColor color, SkColorSpace* dst) {
return SkColor4f_from_SkColor(color, dst).premul();
}
#endif
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