[cairo] How do I use an XRender Picture as a Cairo surface?

[adlo]

xfwm4's window previews seem to be scaled fast enough, and at a quality intermediate to that of CAIRO_FILTER_FAST and CAIRO_FILTER_GOOD. I suppose it uses XRender, but what could it be doing?

Also, if I choose CAIRO_FILTER_GOOD, my previews do not update in response to X11 Damage events. If I use CAIRO_FILTER_FAST, it works properly. Why is this, and how could I resolve this?

Regards

adlo



> On 19 Aug 2015, at 01:52, Bill Spitzak <spitzak at gmail.com> wrote:
> 
> 
> 
>> On Tue, Aug 18, 2015 at 2:24 PM, adlo <adloconwy at gmail.com> wrote:
>> > On 18 Aug 2015, at 19:13, Uli Schlachter <psychon at znc.in> wrote:
>> >
>> > Why do you want to use a picture instead of directly using the drawable?
>> 
>> I am writing a GTK2 program that gets previews/screenshots of all open windows. My program scales the previews and puts them in GtkImages.
>> 
>> CAIRO_FILTER_FAST gives rather low-quality results, but CAIRO_FILTER_GOOD is rather slow.
>> 
>> I wanted to try scaling the previews using XRender in order to find out if it is any better or faster compared to Cairo scaling.
> 
> Unfortunatly XRender is going to give the the exact same results as CAIRO_FILTER_FAST.
> 
>  
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