Graphics Programs Reference
In-Depth Information
Tip
The output resolution of a Mix node will be the same as the background node
resolution.
Blending modes
•
Mix
: In this mode, by using the alpha values, the foreground pixels are placed
over the background pixels.
•
Add
(A+B): In this mode, the pixels from both images are added.
•
Subtract
(A-B): In this mode, the pixels from the foreground are subtracted
from the background.
•
Multiply
(A*B): This mode results in a darker output than either pixel in most
cases (the exception is if any of them is white). This works in a similar way
to conventional math multiplication. The behavior is opposite to the Screen
mode.
•
Screen
[1-(1-A)*(1-B)]: In this mode, both images' pixel values are inverted
and multiplied by each other and then the result is again inverted. This out-
puts a brighter result compared to both input pixels in many cases (except if
one of the pixels is black). Black pixels do not change the background pixels
at all (and vice versa); similarly, white pixels give a white output. This beha-
vior is the opposite of the
Multiply
mode.
•
Overlay
{If A<=0.5, then (2*A)*B, else 1-[1-2*(A-0.5)]*(1-B)}: This mode is a
combination of the
Screen
and
Multiply
modes, and is based on the base
color.
•
Divide
(A/B): In this mode, the background pixels are divided by the fore-
ground pixels. If the foreground is white, the background isn't changed. The
darker the foreground, the brighter is the output [division by 0.5 (median
