# Colours

The Colour object:

- A `Colour` is a structure:

      	struct Colour {
      		byte alpha;
      		byte red;
      		byte green;
      		byte blue;
      	};

- The maximum value of any byte is 0xFF (decimal 255) and minimum value is 0.
- The first byte stores the alpha channel transparency information. 0 means opaque, FF means fully transparent.
- The next three bytes give the intensity of red, green and blue light.
- So {0,0xFF,0,0} is bright red, and {0,0x7F,0,0x7F} is dark purple.
- Colours can be constructed with the `rgb` function.

Predefined colours:

      #define TRANSPARENT     argb(0xFF,0xFF,0xFF,0xFF)

      #define BLACK           rgb(0x00,0x00,0x00)
      #define WHITE           rgb(0xFF,0xFF,0xFF)
      #define BLUE            rgb(0x00,0x00,0xFF)
      #define YELLOW          rgb(0xFF,0xFF,0x00)
      #define GREEN           rgb(0x00,0xFF,0x00)
      #define MAGENTA         rgb(0xFF,0x00,0xFF)
      #define RED             rgb(0xFF,0x00,0x00)
      #define CYAN            rgb(0x00,0xFF,0xFF)

      #define GREY            rgb(0x80,0x80,0x80)
      #define GRAY            rgb(0x80,0x80,0x80)
      #define LIGHT_GREY      rgb(0xC0,0xC0,0xC0)
      #define LIGHT_GRAY      rgb(0xC0,0xC0,0xC0)
      #define PALE_GREY       rgb(0xE0,0xE0,0xE0)
      #define PALE_GRAY       rgb(0xE0,0xE0,0xE0)
      #define DARK_GREY       rgb(0x40,0x40,0x40)
      #define DARK_GRAY       rgb(0x40,0x40,0x40)

      #define DARK_BLUE       rgb(0x00,0x00,0x80)
      #define DARK_GREEN      rgb(0x00,0x80,0x00)
      #define DARK_RED        rgb(0x80,0x00,0x00)
      #define LIGHT_BLUE      rgb(0x80,0xC0,0xFF)
      #define LIGHT_GREEN     rgb(0x80,0xFF,0x80)
      #define LIGHT_RED       rgb(0xFF,0xC0,0xFF)
      #define PINK            rgb(0xFF,0xAF,0xAF)
      #define BROWN           rgb(0x60,0x30,0x00)
      #define ORANGE          rgb(0xFF,0x80,0x00)
      #define PURPLE          rgb(0xC0,0x00,0xFF)
      #define LIME            rgb(0x80,0xFF,0x00)