pw_graphics/pw_color/public/pw_color/color.h

// Copyright 2024 The Pigweed Authors
//
// 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
//
//     https://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.
#pragma once

#include <math.h>
#include <stdint.h>

#include <cinttypes>
#include <cstdint>

/// @defgroup pw_color

namespace pw::color {

/// @ingroup pw_color
///
/// Base type for rgb8888.
typedef uint32_t color_rgba8888_t;

/// @ingroup pw_color
///
/// Base type for rgb564.
typedef uint16_t color_rgb565_t;

/// @ingroup pw_color
///
/// Class for converting between RGB values, RGB565 and RGBA8888 formats.
class ColorRgba {
 public:
  uint8_t r;
  uint8_t g;
  uint8_t b;
  uint8_t a;

  /// Instantiate from individual red, green and blue unsigned integers. Alpha
  /// is set to the max of 255.
  ColorRgba(uint8_t red, uint8_t green, uint8_t blue) {
    r = red;
    g = green;
    b = blue;
    a = 255;
  }

  /// Instantiate from individual red, green, blue and alpha unsigned integers.
  ColorRgba(uint8_t red, uint8_t green, uint8_t blue, uint8_t alpha) {
    r = red;
    g = green;
    b = blue;
    a = alpha;
  }

  /// Instantiate from a 16 bit rgb565 value. This will scale each color to 8
  /// bits per pixel.
  ColorRgba(color_rgb565_t rgb565) {
    // Grab the RGB bits
    uint8_t ir = (rgb565 & 0xF800) >> 11;
    uint8_t ig = (rgb565 & 0x7E0) >> 5;
    uint8_t ib = rgb565 & 0x1F;
    // Scale RGB values to 8bits each
    r = 255 * ir / 31;
    g = 255 * ig / 63;
    b = 255 * ib / 31;
    a = 255;
  }

  /// Instantiate from a 32 bit rgb8888 value.
  ColorRgba(color_rgba8888_t rgba8888) {
    a = (rgba8888 & 0xFF000000) >> 24;
    b = (rgba8888 & 0xFF0000) >> 16;
    g = (rgba8888 & 0xFF00) >> 8;
    r = (rgba8888 & 0xFF);
  }

  /// Return a 16 bit rgb565 value.
  color_rgb565_t ToRgb565() {
    return ((r & 0xF8) << 8) | ((g & 0xFC) << 3) | ((b & 0xF8) >> 3);
  }
};

}  // namespace pw::color