diff --git a/Userland/Libraries/LibGfx/Gamma.h b/Userland/Libraries/LibGfx/Gamma.h deleted file mode 100644 index 970961d048..0000000000 --- a/Userland/Libraries/LibGfx/Gamma.h +++ /dev/null @@ -1,121 +0,0 @@ -/* - * Copyright (c) 2020, the SerenityOS developers. - * - * SPDX-License-Identifier: BSD-2-Clause - */ - -#pragma once - -#include "Color.h" -#include - -#ifdef __SSE__ -# include -#endif - -#include -#include - -#define GAMMA 2.2 - -// Most computer graphics are stored in the sRGB color space, which stores something close to -// the square root of the display intensity of each color channel. This is problematic for most -// operations that we want to perform on colors, since they typically assume that color scales -// linearly (e.g. rgb(127, 0, 0) is half as bright as rgb(255, 0, 0)). This causes incorrect -// results that look more gray than they should, to fix this we have to convert colors to the linear -// color space before performing these operations, then convert back before displaying. -// -// Conversion between linear and sRGB spaces are somewhat expensive to do on the CPU, so we instead -// interpret sRGB colors as gamma2.2 colors, which are close enough in most cases to be indistinguishable. -// Gamma 2.2 colors follow the simple rule of `display_intensity = pow(stored_intensity, 2.2)`. -// This module implements some fast color space transforms between the gamma2.2 and linear color spaces, plus -// some common primitive operations like blending. -// -// For a more in-depth overview of how gamma-adjustment works, check out: -// https://blog.johnnovak.net/2016/09/21/what-every-coder-should-know-about-gamma/ - -namespace Gfx { - -using AK::SIMD::f32x4; - -#ifdef __SSE__ - -// Transform f32x4 from gamma2.2 space to linear space -// Assumes x is in range [0, 1] -constexpr f32x4 gamma_to_linear4(f32x4 x) -{ - return (0.8f + 0.2f * x) * x * x; -} - -// Transform f32x4 from linear space to gamma2.2 space -// Assumes x is in range [0, 1] -inline f32x4 linear_to_gamma4(f32x4 x) -{ - // Source for approximation: https://mimosa-pudica.net/fast-gamma/ - constexpr float a = 0.00279491f; - constexpr float b = 1.15907984f; - float c = (b * AK::rsqrt(1.0f + a)) - 1; - return ((b * AK::SIMD::rsqrt(x + a)) - c) * x; -} - -// Linearize v1 and v2, lerp them by mix factor, then convert back. -// The output is entirely v1 when mix = 0 and entirely v2 when mix = 1 -inline f32x4 gamma_accurate_lerp4(f32x4 v1, f32x4 v2, float mix) -{ - return linear_to_gamma4(gamma_to_linear4(v1) * (1 - mix) + gamma_to_linear4(v2) * mix); -} - -#endif - -// Transform scalar from gamma2.2 space to linear space -// Assumes x is in range [0, 1] -constexpr float gamma_to_linear(float x) -{ - return (0.8f + 0.2f * x) * x * x; -} - -// Transform scalar from linear space to gamma2.2 space -// Assumes x is in range [0, 1] -inline float linear_to_gamma(float x) -{ - // Source for approximation: https://mimosa-pudica.net/fast-gamma/ - constexpr float a = 0.00279491; - constexpr float b = 1.15907984; - float c = (b * AK::rsqrt(1 + a)) - 1; - return ((b * AK::rsqrt(x + a)) - c) * x; -} - -// Linearize v1 and v2, lerp them by mix factor, then convert back. -// The output is entirely v1 when mix = 0 and entirely v2 when mix = 1 -inline float gamma_accurate_lerp(float v1, float v2, float mix) -{ - return linear_to_gamma(gamma_to_linear(v1) * (1 - mix) + gamma_to_linear(v2) * mix); -} - -// Convert a and b to linear space, blend them by mix factor, then convert back. -// The output is entirely a when mix = 0 and entirely b when mix = 1 -inline Color gamma_accurate_blend(Color a, Color b, float mix) -{ -#ifdef __SSE__ - f32x4 ac = { - (float)a.red(), - (float)a.green(), - (float)a.blue(), - }; - f32x4 bc = { - (float)b.red(), - (float)b.green(), - (float)b.blue(), - }; - f32x4 out = 255.f * gamma_accurate_lerp4(ac * (1.f / 255.f), bc * (1.f / 255.f), mix); - return Color(out[0], out[1], out[2]); -#else - return { - static_cast(255.f * gamma_accurate_lerp(a.red() / 255.f, b.red() / 255.f, mix)), - static_cast(255.f * gamma_accurate_lerp(a.green() / 255.f, b.green() / 255.f, mix)), - static_cast(255.f * gamma_accurate_lerp(a.blue() / 255.f, b.blue() / 255.f, mix)), - }; -#endif -} - -} diff --git a/Userland/Libraries/LibGfx/Painter.cpp b/Userland/Libraries/LibGfx/Painter.cpp index 62044519cc..99cf89e453 100644 --- a/Userland/Libraries/LibGfx/Painter.cpp +++ b/Userland/Libraries/LibGfx/Painter.cpp @@ -14,7 +14,6 @@ #include "Bitmap.h" #include "Font/Emoji.h" #include "Font/Font.h" -#include "Gamma.h" #include #include #include