[cairo] bounded operators

[L A]

+ cairo list  ,sorry about the repost..

On Sat, Nov 6, 2010 at 3:11 AM, Andrea Canciani <ranma42 at gmail.com> wrote:
> On Sat, Nov 6, 2010 at 11:03 AM, L A <l.thee.a at gmail.com> wrote:
>> Probably a stupid question: why are CAIRO_OPERATOR_SOURCE and
>> CAIRO_OPERATOR_CLEAR not bounded? _cairo_operator_bounded_by_source
>> call seems to be returning false for these two.
>
> They are bounded by the mask, not by the souce (see
> _cairo_operator_bounded_by_mask).
> You might also want a high level overview of the operators:
> http://cairographics.org/operators/
> Notice that throughout the whole document "bounded" means "bounded by mask" (as
> explained in the section "The Source").
>
> Andrea
>

Thanks, that makes sense. Another question: if the mask is empty (ie:
NULL), can we assume that op is source bounded?