Foundation > Image Processing Filters > IlvBitmapFilter: The Image Processing Class > The IlvBlendFilter Class
 
The IlvBlendFilter Class
The IlvBlendFilter class lets you blend two images A and B using various modes.
The blend modes define the following formulas:
*Normal Blend Mode: cr = (1 - qa) * cb + ca
*Multiply Blend Mode: cr = (1 - qa) * cb + (1 - qb) * ca + ca * cb
*Screen Blend Mode: cr = cb + ca - ca * cb
*Darken Blend Mode: cr = Min((1 - qa) * cb + ca, (1 - qb) * ca + cb)
*Lighten Blend Mode: cr = Max((1 - qa) * cb + ca, (1 - qb) * ca + cb)
where:
cr
Result color (RGB) - premultiplied
qa
Opacity value at a given pixel for image A
qb
Opacity value at a given pixel for image B
ca
Color (RGB) at a given pixel for image A (premultiplied)
cb
Color (RGB) at a given pixel for image B (premultiplied)
For all blend modes, the resulting opacity qr is computed as follows:
qr = 1 - (1 - qa) * (1 - qb)

Version 6.1
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