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 <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 = 0xFF009688,
            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);
} /* namespace uirenderer */
} /* namespace android */

#endif /* COLOR_H */