[cairo] clipmask of multiple rects in different angles

[Theo Veenker]

On 07/20/2016 01:44 PM, Enrico Weigelt, metux IT consult wrote:
> On 20.07.2016 13:37, Enrico Weigelt, metux IT consult wrote:
>
> <snip>
>
> If all rects would just have angle 0, it perhaps could be trivial,
> just paint a bunch of rects, but call cairo_clip instead of cairo_fill.
>
> But what about transformation matrices ? When are they applied ?
> For each draw new path element (cairo_rectangle, etc) or only on the
> final path ?

Not an answer to your question, but if you just take the bounding box of the modified 
element and use that as a clip mask and clear and redraw everything that is in or partly 
in the box you can get very good performance in my experience.

There has been talk on this list about damage tracking but I believe it never got concrete.

Theo