[cairo] cairo/inkscape problems

Behdad Esfahbod behdad at behdad.org
Wed Feb 21 09:32:58 PST 2007

On Wed, 2007-02-21 at 11:39 -0500, bulia byak wrote:
> 1. The 1-byte surface is broken unless the stride is divisible by four
> (a known problem according to Carl). If I make my own buffers for each
> object I can work around this, but I'm optimizing and trying to use
> existing buffers, and some of them are already clipped and cannot be
> extended.

Yes, known.  This is the XFAIL test a8-mask.  There is a draft patch


Please test and let us know if it helps.

> 2. Large paths disappear on close zoom. Carl says it's a precision
> problem. You'll need to compile and run Inkscape SVN to see that.
> Switch to Outline mode (View > Display mode), draw a path larger than
> the page, and zoom into it. At some point it disappears.
> 3. This may be related to 2. In a complex drawing with lots of paths,
> zooming in too closely shows lots of random stray lines all over the
> screen. Open share/examples/gallardo.svgz from Inkscape distribution,
> switch to Outline and zoom into an area where many paths are close to
> each other. At about 5000%, the pandemonium starts. 

Yes, both are the same issue, XFAIL test long-lines.  We may be
switching from 16.16 fixed point to 24.8.  That will help here a lot,
but would not completely fix it.  No idea about the real fix, but it
shouldn't be that hard.  We just need to detect overflows when
converting doubles to fixed and act appropriately.  Anyone taking this?


"Those who would give up Essential Liberty to purchase a little
 Temporary Safety, deserve neither Liberty nor Safety."
        -- Benjamin Franklin, 1759

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