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| Release 4.0 | ||
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Predefined Functions - lum
| Function name: | lum - Return luminance of argument |
| Synopsis: | lum(c) |
| Input data type | Output data type |
|---|---|
| color | real |
Description:
This function takes a color variable as input and returns the luminance of the color. The luminance of a color is always between 0 and 1. For more information about hue, saturation and luminance see HSL Colorspace.
Colors can be created by using one of the color creation functions:
Internally colors are stored in RGBA format. So in order to return the luminance of a color, this function needs to do a color space conversion, which is quite slow.