lib-open-smartwatch/gfx_util.cpp at master · Open-Smartwatch/lib-open-smartwatch · GitHub

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#include "gfx_util.h"

#ifdef OSW_EMULATOR
#include "FakeArduino.h"
#else
#include <Arduino.h>
#endif

uint16_t rgb565(uint8_t red, uint8_t green, uint8_t blue) {
  return ((red & 0b00011111000) << 8) | ((green & 0b00011111100) << 3) | (blue >> 3);
}

uint32_t rgb888(uint8_t red, uint8_t green, uint8_t blue) {
  return ((uint32_t)red << 16) | ((uint32_t)green << 8) | (uint32_t)blue;
}

uint16_t rgb888to565(uint32_t rgb888) { return rgb565(rgb888_red(rgb888), rgb888_green(rgb888), rgb888_blue(rgb888)); }

uint32_t rgb565to888(uint16_t rgb565) { return rgb888(rgb565_red(rgb565), rgb565_green(rgb565), rgb565_blue(rgb565)); }

uint16_t blend(uint16_t target, uint16_t source, float alpha) {
  uint8_t r = rgb565_red(source) * alpha + rgb565_red(target) * (1.0 - alpha);
  uint8_t g = rgb565_green(source) * alpha + rgb565_green(target) * (1.0 - alpha);
  uint8_t b = rgb565_blue(source) * alpha + rgb565_blue(target) * (1.0 - alpha);

  return rgb565(r, g, b);
}

/**
 * @brief Calculated the color code of a dimmed color
 *
 * @param oc Color code
 * @param amount Amount to dimmed.
 * @return uint16_t Color code of the dimmed color.
 */
uint16_t dimColor(uint16_t oc, uint8_t amount) {
  uint16_t r = rgb565_red(oc);
  uint16_t g = rgb565_green(oc);
  uint16_t b = rgb565_blue(oc);
  r = r >= amount ? r - amount : 0;
  g = g >= amount * 2 ? g - amount * 2 : 0;
  b = b >= amount ? b - amount : 0;

  uint16_t nc = rgb565(r, g, b);
  return nc;
}

uint16_t changeColor(uint16_t oc, float amount) {
  uint16_t r = rgb565_red(oc);
  uint16_t g = rgb565_green(oc);
  uint16_t b = rgb565_blue(oc);
  r = r * amount;
  g = g * amount;
  b = b * amount;

  uint16_t nc = rgb565(r, g, b);
  return nc;
}

uint8_t rgb565_red(uint16_t rgb565) {
  // |rrrrrggg|gggbbbbb|
  return (rgb565 >> 8) & 0b11111000;
}

uint8_t rgb565_green(uint16_t rgb565) {
  // |rrrrrggg|gggbbbbb|
  return (rgb565 >> 3) & 0b11111100;
}

uint8_t rgb565_blue(uint16_t rgb565) {
  // |rrrrrggg|gggbbbbb|
  return (rgb565 << 3);
}

uint8_t rgb888_red(uint32_t rgb888) {
  // |rrrrrrrr|gggggggg|bbbbbbbb|
  return rgb888 >> 16;
}

uint8_t rgb888_green(uint32_t rgb888) {
  // |rrrrrrrr|gggggggg|bbbbbbbb|
  return rgb888 >> 8;
}

uint8_t rgb888_blue(uint32_t rgb888) {
  // |rrrrrrrr|gggggggg|bbbbbbbb|
  return rgb888;
}

// Shamelessly copied from
// https://stackoverflow.com/questions/3018313/algorithm-to-convert-rgb-to-hsv-and-hsv-to-rgb-in-range-0-255-for-both
void hsvToRgb(const unsigned char& h, const unsigned char& s, const unsigned char& v, unsigned char& r,
              unsigned char& g, unsigned char& b) {
  unsigned char region, remainder, p, q, t;

  if (s == 0) {
    r = v;
    g = v;
    b = v;
    return;
  }

  region = h / 43;
  remainder = (h - (region * 43)) * 6;

  p = (v * (255 - s)) >> 8;
  q = (v * (255 - ((s * remainder) >> 8))) >> 8;
  t = (v * (255 - ((s * (255 - remainder)) >> 8))) >> 8;

  switch (region) {
    case 0:
      r = v;
      g = t;
      b = p;
      break;
    case 1:
      r = q;
      g = v;
      b = p;
      break;
    case 2:
      r = p;
      g = v;
      b = t;
      break;
    case 3:
      r = p;
      g = q;
      b = v;
      break;
    case 4:
      r = t;
      g = p;
      b = v;
      break;
    default:
      r = v;
      g = p;
      b = q;
      break;
  }
}

// Also shamelessly copied from
// https://stackoverflow.com/questions/3018313/algorithm-to-convert-rgb-to-hsv-and-hsv-to-rgb-in-range-0-255-for-both
void rgbToHsv(const unsigned char& r, const unsigned char& g, const unsigned char& b, unsigned char& h,
              unsigned char& s, unsigned char& v) {
  unsigned char rgbMin, rgbMax;

  rgbMin = r < g ? (r < b ? r : b) : (g < b ? g : b);
  rgbMax = r > g ? (r > b ? r : b) : (g > b ? g : b);

  v = rgbMax;
  if (v == 0) {
    h = 0;
    s = 0;
    return;
  }

  s = 255 * long(rgbMax - rgbMin) / v;
  if (s == 0) {
    h = 0;
    return;
  }

  if (rgbMax == r)
    h = 0 + 43 * (g - b) / (rgbMax - rgbMin);
  else if (rgbMax == g)
    h = 85 + 43 * (b - r) / (rgbMax - rgbMin);
  else
    h = 171 + 43 * (r - g) / (rgbMax - rgbMin);
};