CAIRO_OPERATOR_XOR documentation
Richard Billington <[email protected]>
| Newsgroups | gmane.comp.lib.cairo |
|---|---|
| Message-ID | <[email protected]> |
If I interpret this correctly (quoting from
http://cairographics.org/operators/):
Resulting alpha (aR) Resulting color (xR)
aA + aB − 2·aA·aB (xaA·(1−aB) + xaB·(1−aA))/aR
If the alpha value for both A and B is 1, then nothing will be drawn
anywhere? That is, I have something drawn on surface A with alpha at
1.0, and I have something on the receiving surface drawn with alpha at
1.0. This results in aR = 0.0 so everything in B becomes transparent?
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