framework-arduinoteensy-cxx20/libraries/ssd1351/color.h

#pragma once
#include <Arduino.h>

namespace ssd1351 {

typedef uint8_t IndexedColor;
typedef	uint16_t LowColor;
struct HighColor {
	uint8_t r = 0;
	uint8_t g = 0;
	uint8_t b = 0;

	HighColor() {}
	HighColor(int16_t _r, int16_t _g, int16_t _b) : r(_r), g(_g), b(_b) {}
};

struct RGB {
	uint8_t r = 0;
	uint8_t g = 0;
	uint8_t b = 0;

	uint8_t __attribute__((always_inline)) clamp(int16_t val) {
		val = val > 255 ? 255 : val;
		return val < 0 ? 0 : val;
	}

	RGB(const LowColor encoded) {
		r = (encoded & 0xf800) >> 8;
		g = (encoded & 0x7E0) >> 3;
		b = (encoded & 0x1F) << 3;
	}

	RGB(const HighColor &c) {
		r = c.r << 2;
		g = c.g << 2;
		b = c.b << 2;
	}

	RGB(int16_t _r = 0, int16_t _g = 0, int16_t _b = 0) {
		r = clamp(_r);
		g = clamp(_g);
		b = clamp(_b);
	}

	operator HighColor() const {
		return HighColor(r, g, b);
	}

	operator LowColor() const {
		// Encode 3 byte colour into two byte (5r/6g/5b) color
		// Masks the last three bits of red/blue, last two bits of green
		// and shifts colours up to make RRRR RGGG GGGB BBBB
		return ((r & 0xF8) << 8) | ((g & 0xFC) << 3) | ((b & 0xF8) >> 3);
	}

	operator IndexedColor() const {
		return (r & 0xE0) | ((g & 0xE0) >> 3) | (b >> 6);
	}
};
}