[cairo] Re : Re : Re : Re : multithreaded bug in cairo on call to cairo stroke?

Andrea Canciani ranma42 at gmail.com
Wed Dec 15 09:09:20 PST 2010

On Wed, Dec 15, 2010 at 4:27 PM, Philippe Leroux <lerouxp at yahoo.ca> wrote:
> ya pixman/simpleops is fine for me now
> out of curiosity
> so if i change the source to a random pattern just after i created the context
> (in each threads)
> would that force cairo to use a seperate source for each thread? and be kind of
> a workaround?
> because, i tried and it doesnt seems to work

It's slightly harder than that, because cairo is clever enough to
notice if you are
actually using the same pattern.
For example, if you create a solid color using a gradients whose color stops
all have the same color, cairo will usually optimize it to a solid color.
To actually force disctinct sources you would probably have to use surface
patterns, but I think this would cause major slowdowns.

> i also tested your second patch (and without pixman/simplops)
> works fine, with colors !

Very good. We don't have a clean fix yet, but at least we know how
it can be fixed.


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