[cairo] Trapezoid bounding box computations
Keith Packard
keithp at keithp.com
Tue Sep 7 18:49:14 PDT 2004
When filling polygons, we have to compute the bounding box of a set of
trapezoids. Currently, that's done after the trapezoids are generated
through a relatively expensive mechanism.
I've got code sitting here which does this incrementally while the
trapezoids are being generated. For the current trapezoid model, it also
computes a 'lazy' bounding box, using the coordinates of each segment
endpoint instead of computing approximate trapezoid vertices. This is
"correct" for Cairo which uses only polygon vertices for the trapezoid
segment endpoints, and hence for which the trapezoid segment endpoints are
sufficient globally, if not locally for each trapezoid.
Should I just throw this away in anticipation of the new tesselation code?
Or would the incremental bounding box computations make sense in any case?
-keith
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