| LumaKey |
Function
The LumaKey function creates a key in the alpha channels based on overall luminance. Values below loVal are set to zero, and values above hiVal are set to 1. Values in between are ramped. You also have roll-off control, and an mMult toggle. This is a fast way to place the luminance of an image into the alpha layer, but this can also be done with a Reorder set to rgbl.
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Parameters
|
Type
|
Defaults
|
Function
|
| loVal |
float
|
0 | Any pixel below this value (as calculated per its luminance) turns black. |
| hiVal |
float
|
1 | Any pixel above this value (as calculated by its luminanace) turns white. |
| lo,hiSmooth |
float
|
0,0, |
A rolloff factor to provide a smooth dropoff. |
| mMult |
int
|
0 |
automatic pre-multiplification of the RGB channels. 0 = no pre-multiply |
Synopsis
image LumaKey( image, float loVal, float hiVal, float loSmooth, float hiSmooth, int mMult );
Script
image = LumaKey( image, loVal, hiVal, loSmooth, hiSmooth, mMult );
Command Line
shake -lumakey loVal hiVal loSmooth etc...