2011

Table Of Contents
Result:Operator
The output will be equal to the generated mask (front) except that the
part of the front overlapping the previously composited masks (back) will
be missing. No part of the back will be visible in the output in any case.
Outside
The output will be equal to the previously composited mask (back) except
that the part of the back covered by the generated masks (front) will be
Cutout
missing. No part of the front will be visible in the output in any case. Ba-
sically this operator is equal to the Outside operator with the front and
back roles reversed.
Both generated mask (front) and previously composited masks (back) are
copied to the output except for the part where they overlap.
Xor
Global Composite Operators
The following table lists the compositing operators applicable between the
input image and previously composited masks:
Result:Operator
Composites the previously composited masks (front) over the input image
(back). The output will cover any area covered by either the front or the
back. Where the front and back overlap, the output will show the front.
Over
Completely replaces the input image alpha channel with the previously
composited masks.
Replace
Similar to the Over operator, but the output will cover the same area
covered by the input image alpha channel.
Atop
Composites the previously composited masks (front) over the input image
alpha channel (back), but the output will cover only the area covered by
both front and back.
Inside
The output will be equal to the previously composited masks (front) except
that the part of the front overlapping the input image alpha channel (back)
Outside
will be missing. No part of the back will be visible in the output in any
case.
The output will be equal to the input image alpha channel (back) except
that the part of the back covered by the previously composited masks
Cutout
(front) will be missing. No part of the front will be visible in the output in
564 | Chapter 23 Masking