[cairo] Fill not overlapping stroke?

[Bill Spitzak]

David Trallero wrote:
>> I suppose what I want is a way to just fill inside the stroke and not overlap it;
>> or a way to pass fill and stroke at the same time.
> 
> If I understood you well, you are looking for something like this:
> 
>     cairo_push_group_with_content( cr, CAIRO_CONTENT_COLOR_ALPHA ) ;
>       cairo_set_line_width( cr, 10.0 ) ;
> 
>       cairo_rectangle( cr, 0, 0, 200, 200 ) ;
> 
>       cairo_set_source_rgba( cr, 1.0, 0.0, 0.0, .8 ) ;
>       cairo_fill_preserve( cr ) ;
> 
>       cairo_set_operator( cr, CAIRO_OPERATOR_DEST_OUT ) ;
> 
>       cairo_set_source_rgba( cr, 0.0, 0.0, 0.0, .5 ) ;
>       cairo_stroke( cr ) ;
> 
>     cairo_pop_group_to_source( cr ) ;
>     cairo_set_operator( cr, CAIRO_OPERATOR_DEST_OVER ) ;
>     cairo_paint( cr );

I think to make the stroke be an arbitrary color and alpha, you instead 
use CAIRO_OPERATOR_SOURCE when doing the stroke step.