[Xr] Xr API comments
keithp at keithp.com
Tue May 27 21:34:12 PDT 2003
Around 15 o'clock on May 27, Carl Worth wrote:
> If there were a formal Xr specification, it would guarantee that the
> effect of drawing with an arc would deviate at most "tolerance" device
> pixels from the geometrically correct result.
One additional useful constraint is that an arc from 0 to x trace a path
which is (really close to) a subset of the path traced by an arc from 0 to
x + dx. I don't think it matters whether we define arcs in terms of
splines or lines; although splines won't involve any joins if done
> Hmmm... After typing that, I'm wondering if we want to come up with
> a definition for tolerance other than device pixels that would make
> more sense for ridiculously high-resolution devices.
No, I think ridiculously high-resolution devices should generate
ridiculously high-precision output. That's how postscript is defined.
> I think circular arcs are a special case that merit direct support.
Circular perhaps, but elliptical arcs have axes to define, which are a
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