[cairo] dash phase oddity

Baz brian.ewins at gmail.com
Mon Jun 25 13:10:03 PDT 2007

On 25/06/07, Carl Worth <cworth at cworth.org> wrote:
> On Mon, 25 Jun 2007 20:24:38 +0100, Baz wrote:
> > ... but of course dash-zero-len now fails. Ok, forget it - it now
> > looks like I have to extend every dash-on by FLT_EPSILON at each end,
> > shrink the dash-off segments, and add FLT_EPSILON to the phase to get
> > the same output as the image backend! A new ref image seems more
> > sensible.
> What's your justification for using a reference image that would
> codify different output on different backends?

Simply because this seemed like a hack. It seems that cairo has made a
choice that dash-on is an inclusive interval, dash-off is an exclusive
interval, and quartz has made the opposite choice. So the rendering
difference is at the point where two floating point numbers are
exactly equal, which isn't great.

I'll make the change i suggested though and see if it works.
> A fundamental design criteria of cairo is that we strive for
> consistent output across the various backends.


> -Carl

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