“Conjoint-Over” Operator
Lawrence D'Oliveiro <[email protected]>
| Newsgroups | gmane.comp.lib.cairo |
|---|---|
| Organization | Geek Central |
| Message-ID | <[email protected]> |
Keith Packard published a description quite a while ago <http://marc.info/?l=xfree-render&m=99792000027857&w=2> of additional “conjoint” and “disjoint” variants of the traditional Porter-Duff operators. This sample script <https://github.com/ldo/python_pixman_examples/blob/master/conjoint_over> illustrates the difference between the original Porter-Duff “over” operator with the conjoint and disjoint variants, in the particular situation that Keith was concerned with, namely accumulating increasing opacity with multiple passes of a brush. True enough, the conjoint-over version seems to give something closest to the original colour, certainly in the earlier passes. -- cairo mailing list [email protected] http://lists.cairographics.org/mailman/listinfo/cairo