The HSB curve is a curve adjusting work under 'Hue-Saturation-Brightness' colour space that allows the user to set different parameters by the coordinate axis of hue value. This function supports 3 channels in HSB colour space. Some typical usages of this function for are:
Give different saturation to different colours.
Keep one or two colours, and make others gray.
Change colour of cloth by selecting an area and adjust offset on the accordant colour in the ‘Hue’ channel.
Darken or lighten a colour, working in the ‘Luminance’ channel.
