utils.h

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2023 AUTHORS
 *
 * Released under GNU GPL v2+, read the file 'COPYING' for more information.
 */
#ifndef SEEN_COLORS_UTILS_H
#define SEEN_COLORS_UTILS_H
 
#include <algorithm>
#include <cstdint>
#include <optional>
#include <string>
#include <vector>
#include <algorithm>
 
/* Useful composition macros */
 
constexpr double SP_COLOR_U_TO_F(uint32_t v)
{
    return v / 255.0;
}
constexpr uint32_t SP_COLOR_F_TO_U(double v)
{
    return (unsigned int)(std::clamp(v, 0.0, 1.0) * 255. + .5);
}
constexpr uint32_t SP_RGBA32_R_U(uint32_t v)
{
    return (v >> 24) & 0xff;
}
constexpr uint32_t SP_RGBA32_G_U(uint32_t v)
{
    return (v >> 16) & 0xff;
}
constexpr uint32_t SP_RGBA32_B_U(uint32_t v)
{
    return (v >> 8) & 0xff;
}
constexpr uint32_t SP_RGBA32_A_U(uint32_t v)
{
    return v & 0xff;
}
constexpr double SP_RGBA32_R_F(uint32_t v)
{
    return SP_COLOR_U_TO_F(SP_RGBA32_R_U(v));
}
constexpr double SP_RGBA32_G_F(uint32_t v)
{
    return SP_COLOR_U_TO_F(SP_RGBA32_G_U(v));
}
constexpr double SP_RGBA32_B_F(uint32_t v)
{
    return SP_COLOR_U_TO_F(SP_RGBA32_B_U(v));
}
constexpr double SP_RGBA32_A_F(uint32_t v)
{
    return SP_COLOR_U_TO_F(SP_RGBA32_A_U(v));
}
 
constexpr uint32_t SP_RGBA32_U_COMPOSE(uint32_t r, uint32_t g, uint32_t b, uint32_t a)
{
    return ((r & 0xff) << 24) | ((g & 0xff) << 16) | ((b & 0xff) << 8) | (a & 0xff);
}
constexpr uint32_t SP_RGBA32_F_COMPOSE(double r, double g, double b, double a)
{
    return SP_RGBA32_U_COMPOSE(SP_COLOR_F_TO_U(r), SP_COLOR_F_TO_U(g), SP_COLOR_F_TO_U(b), SP_COLOR_F_TO_U(a));
}
constexpr uint32_t SP_RGBA32_C_COMPOSE(uint32_t c, double o)
{
    return SP_RGBA32_U_COMPOSE(SP_RGBA32_R_U(c), SP_RGBA32_G_U(c), SP_RGBA32_B_U(c), SP_COLOR_F_TO_U(o));
}
 
constexpr uint32_t compose_argb32(double a, double r, double g, double b) {
    return SP_RGBA32_U_COMPOSE(SP_COLOR_F_TO_U(a), SP_COLOR_F_TO_U(r), SP_COLOR_F_TO_U(g), SP_COLOR_F_TO_U(b));
}
 
namespace Inkscape::Colors {
 
class Color;
 
uint32_t hex_to_rgba(std::string const &value);
std::vector<double> rgba_to_values(uint32_t rgba, bool opacity);
std::string rgba_to_hex(uint32_t value, bool alpha = false);
std::string color_to_id(std::optional<Color> const &color);
std::string desc_to_id(std::string const &desc);
 
Color make_contrasted_color(Color const &orig, double amount);
Color make_theme_color(Color const &orig, bool dark);
 
double lightness(Color color);
double perceptual_lightness(double l);
double get_perceptual_lightness(Color const &color);
std::pair<double, double> get_contrasting_color(double l);
 
} // namespace Inkscape::Colors
 
#endif // SEEN_COLORS_UTILS_H