Re: Quickly drawing non-antialiased, discrete, pixels
Re: Quickly drawing non-antialiased, discrete, pixels
- Subject: Re: Quickly drawing non-antialiased, discrete, pixels
- From: Greg Titus <email@hidden>
- Date: Mon, 6 Jan 2003 15:48:17 -0800
On Monday, January 6, 2003, at 03:10 PM, Dietmar Planitzer wrote:
Apparently, Quartz even takes independent line strips in the current
path
into account when it checks for intersections. There may be a logic to
this
- though it escapes me which one, because it introduces an asymmetry
in the
libraries semantic. Compare independent line strips specified via a
single
path to independent line strips specified as individual paths...
Think of intersecting line strips in a single path, painted with a
color that has some alpha. If you draw the strips in a single path, the
intersecting pixels get painted once (thus the need to calculate
intersections). If you draw the strips in separate paths with separate
strokes or fills, the pixels get painted twice and end up a different
color because of the alpha blending.
This is a very important and intended asymmetry. Stroking a path needs
to result in drawing the effected pixels exactly once, no matter what
the composition of the path.
- Greg
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