[Poppler-bugs] [Bug 14408] Spectacular gradient failure

[bugzilla-daemon at freedesktop.org]

http://bugs.freedesktop.org/show_bug.cgi?id=14408





--- Comment #6 from Carl Worth <cworth at cworth.org>  2008-02-22 09:51:22 PST ---
(In reply to comment #5)
> One of the difficulties in implementing pdf gradients with cairo is how to deal
> with Postscript functions. For example axial gradients have a linearly varying
> parameter but the actual color values are expressed in terms of an arbitrary
> Postscript function. ie. the following is a valid axial gradient, r=sin(t),
> g=cos(t), b=0, where t varies linearly.

Yeah, that could be tricky. One could punt and just call the existing code in a
case like that, (meaning that many of these cases will still draw garbage, but
hopefully the actual usage is rare). Or one could sample that function at
various points in order to compute a static color-stop array suitable for
passing to cairo.

If it can be an arbitrary function though, I suppose it doesn't give you any
guarantees about how smooth it is so that you can know when you've sampled it
enough?

-Carl


-- 
Configure bugmail: http://bugs.freedesktop.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are the assignee for the bug.