[cairo] Real-time ellipse creation - invalid matrix (not invertible) exception

[Lockert Fredrick]

On 23 August 2012 17:56, Carlos López González <genetita at gmail.com> wrote:
> I think that you have to restore after stroke, not before:
>
>
> cr->set_source_rgb(1.0, 1.0, 1.0);
> cr->fill_preserve();
> cr->stroke();
> cr->restore(); /// restore after stroke operation, not before


That would cause the stroke to be scaled with the arc, which would
create an undesired thick line around it.

The problem lies in the arc's scale operation. Whenever it goes from
positive to negative, it sometimes result in an invalid matrix. If the
mouse is moved fast enough though, it doesn't create an exception...
this confuses me more or less.

Thanks for your suggestion though, I really do appreciate it.


- Fredrick