[cairo] Bug in PDF output with independent path/pen transformations

[Carl Worth]

On Thu, 01 Nov 2007 13:31:43 -0400, Behdad Esfahbod wrote:
> On Thu, 2007-11-01 at 23:44 +1030, Adrian Johnson wrote:
>
> > I am not seeing why the resolution of the path coordinates should be
> > linked to the curve flattening tolerance. They are two separate things.
>
> Humm, that's not the way I look at tolerance, though now that I read the
> docs, you are right.  In my opinion though, tolerance is simply the
> error margin acceptable by the user.  If you define it like that, it's
> quite acceptable to use it in rounding.

Yes. I think the documentation is just buggy here. I'd always intended
the tolerance value to express the error that the user is willing to
accept, (for any geometry), and not just used "when converting paths
into trapezoids".

The documentation probably ended up like only because the
implementation wasn't using the tolerance value for much of anything
else.

> > A user may increase the curve flattening tolerance for better
> > performance but still expect all objects to be accurately positioned
> > when imported into another application and rescaled.

I don't follow this. "Better performance" sounds like some interactive
display, while "imported into another application" sounds like some
vector output. If an application wants to distinguish these two cases,
I think it would be quite natural for it to use different tolerance
values in each case.

-Carl
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