< Previous | Contents | Next >
A table containing named entries describing how each channel of the background image should be processed to produce the result. Each entry in the table may contain either a numeric constant value, or a string specifying a channel in the foreground or background image, which is combined using the specified operation to produce the desired result. The channels used in the entry are abbreviations, and the values are strings that read either Fg.channel or Bg.channel. Case is not important. See the Options section below for a list of acceptable channel abbreviations. Some example options tables are shown below:
{ R = "Fg.R", G = "Fg.G", B = "Fg.B", A = "Fg.A" }
{ R = "bg.a", G = "bg.a", B = "bg.a", A = 1.0 }
{ R = blend, G = blend, B = blend, A = blend }