libs/hwui/utils/Color.h

/*
 * Copyright (C) 2015 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#ifndef COLOR_H
#define COLOR_H

#include <math.h>
#include <system/graphics.h>

#include <SkColor.h>
#include <SkColorSpace.h>

namespace android {
namespace uirenderer {
namespace Color {
enum Color {
    Red_500 = 0xFFF44336,
    Pink_500 = 0xFFE91E63,
    Purple_500 = 0xFF9C27B0,
    DeepPurple_500 = 0xFF673AB7,
    Indigo_500 = 0xFF3F51B5,
    Blue_500 = 0xFF2196F3,
    LightBlue_300 = 0xFF4FC3F7,
    LightBlue_500 = 0xFF03A9F4,
    Cyan_500 = 0xFF00BCD4,
    Teal_500 = 0xFF008577,
    Teal_700 = 0xFF00796B,
    Green_500 = 0xFF4CAF50,
    Green_700 = 0xFF388E3C,
    LightGreen_500 = 0xFF8BC34A,
    LightGreen_700 = 0xFF689F38,
    Lime_500 = 0xFFCDDC39,
    Yellow_500 = 0xFFFFEB3B,
    Amber_500 = 0xFFFFC107,
    Orange_500 = 0xFFFF9800,
    DeepOrange_500 = 0xFFFF5722,
    Brown_500 = 0xFF795548,
    Grey_200 = 0xFFEEEEEE,
    Grey_500 = 0xFF9E9E9E,
    Grey_700 = 0xFF616161,
    BlueGrey_500 = 0xFF607D8B,
    Transparent = 0x00000000,
    Black = 0xFF000000,
    White = 0xFFFFFFFF,
};
}

static_assert(Color::White == SK_ColorWHITE, "color format has changed");
static_assert(Color::Black == SK_ColorBLACK, "color format has changed");

// Array of bright (500 intensity) colors for synthetic content
static const Color::Color BrightColors[] = {
        Color::Red_500,    Color::Pink_500,  Color::Purple_500,     Color::DeepPurple_500,
        Color::Indigo_500, Color::Blue_500,  Color::LightBlue_500,  Color::Cyan_500,
        Color::Teal_500,   Color::Green_500, Color::LightGreen_500, Color::Lime_500,
        Color::Yellow_500, Color::Amber_500, Color::Orange_500,     Color::DeepOrange_500,
        Color::Brown_500,  Color::Grey_500,  Color::BlueGrey_500,
};
static constexpr int BrightColorsCount = sizeof(BrightColors) / sizeof(Color::Color);

enum class TransferFunctionType : int8_t { None = 0, Full, Limited, Gamma };

// Opto-electronic conversion function for the sRGB color space
// Takes a linear sRGB value and converts it to a gamma-encoded sRGB value
static constexpr float OECF_sRGB(float linear) {
    // IEC 61966-2-1:1999
    return linear <= 0.0031308f ? linear * 12.92f : (powf(linear, 1.0f / 2.4f) * 1.055f) - 0.055f;
}

// Opto-electronic conversion function for the sRGB color space
// Takes a linear sRGB value and converts it to a gamma-encoded sRGB value
// This function returns the input unmodified if linear blending is not enabled
static constexpr float OECF(float linear) {
#ifdef ANDROID_ENABLE_LINEAR_BLENDING
    return OECF_sRGB(linear);
#else
    return linear;
#endif
}

// Electro-optical conversion function for the sRGB color space
// Takes a gamma-encoded sRGB value and converts it to a linear sRGB value
static constexpr float EOCF_sRGB(float srgb) {
    // IEC 61966-2-1:1999
    return srgb <= 0.04045f ? srgb / 12.92f : powf((srgb + 0.055f) / 1.055f, 2.4f);
}

// Electro-optical conversion function for the sRGB color space
// Takes a gamma-encoded sRGB value and converts it to a linear sRGB value
// This function returns the input unmodified if linear blending is not enabled
static constexpr float EOCF(float srgb) {
#ifdef ANDROID_ENABLE_LINEAR_BLENDING
    return EOCF_sRGB(srgb);
#else
    return srgb;
#endif
}

// Returns whether the specified color space's transfer function can be
// approximated with the native sRGB transfer function. This method
// returns true for sRGB, gamma 2.2 and Display P3 for instance
bool transferFunctionCloseToSRGB(const SkColorSpace* colorSpace);

sk_sp<SkColorSpace> DataSpaceToColorSpace(android_dataspace dataspace);

struct Lab {
    float L;
    float a;
    float b;
};

Lab sRGBToLab(SkColor color);
SkColor LabToSRGB(const Lab& lab, SkAlpha alpha);

} /* namespace uirenderer */
} /* namespace android */

#endif /* COLOR_H */