Predefined Functions – alpha

Function name: alpha – Return alpha component of argument
Synopsis: alpha(c)

Input data type Output data type
color real


This function takes a color variable as input and returns the transparency (alpha value) of the color. Normally the transparency of a color is between 0 and 1. Colors can be created by using one of the color creation functions:

Internally colors are stored in RGBA format, thus this function is fast as it only needs to return one of the stored components of the color.