more visiting and less buffering in drawinglayer/

[Luboš Luňák]

On Friday 03 of December 2021, Noel Grandin wrote:
> What I am doing is attempting to remove the intermediate creation of
> drawinglayer objects (which is fairly expensive), and instead use a visitor
> pattern (represented by the Primitive2DDecompositionVisitor abstract class)

 +1

> Along the way I also intend to remove some buffering of these intermediate
> objects, since it is generally less expensive to just visit the
> higher-level tree.

 In case that would involve removing buffering of bitmaps, please check things 
like https://bugs.documentfoundation.org/show_bug.cgi?id=104878 still work 
well with Skia in software mode. I've implemented a cache in the Skia backend 
to handle cases of drawinglayer being dumb and repeatedly asking to do 
expensive redraws of the same stuff over and over again, which requires that 
the underlying bitmap is the same object and not something created from 
scratch every time.

-- 
 Luboš Luňák
 l.lunak at collabora.com