LibGfx: Remove Gamma.h

It's been unused since c8c065b6b0c30dc.

Userland/Libraries/LibGfx/Gamma.h

@@ -1,121 +0,0 @@
-/*
- * Copyright (c) 2020, the SerenityOS developers.
- *
- * SPDX-License-Identifier: BSD-2-Clause
- */
-
-#pragma once
-
-#include "Color.h"
-#include <AK/Math.h>
-
-#ifdef __SSE__
-#    include <xmmintrin.h>
-#endif
-
-#include <AK/SIMD.h>
-#include <AK/SIMDMath.h>
-
-#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<u8>(255.f * gamma_accurate_lerp(a.red() / 255.f, b.red() / 255.f, mix)),
-        static_cast<u8>(255.f * gamma_accurate_lerp(a.green() / 255.f, b.green() / 255.f, mix)),
-        static_cast<u8>(255.f * gamma_accurate_lerp(a.blue() / 255.f, b.blue() / 255.f, mix)),
-    };
-#endif
-}
-
-}

Userland/Libraries/LibGfx/Painter.cpp

@@ -14,7 +14,6 @@
 #include "Bitmap.h"
 #include "Font/Emoji.h"
 #include "Font/Font.h"
-#include "Gamma.h"
 #include <AK/Assertions.h>
 #include <AK/Debug.h>
 #include <AK/Function.h>