The exported representation of colours is an unsigned 32bit value in host order The value is divided into four 8bit channels. These are: Bits Name Desciption 0-7 Blue The blue intensity of the colour 0 is off 0xff is fully on 8-15 Green The green intensity of the colour 0 is off 0xff is fully on 16-23 Red The red intensity of the colour 0 is off 0xff is fully on 24-31 Alpha The Alpha component represents the opacity of the colour 0 is fully transparent and 0xff is opaque