[cairo] Cairo and WinCe image drawing

Owen Taylor otaylor at redhat.com
Wed Apr 12 07:28:45 PDT 2006


On Wed, 2006-04-12 at 13:45 +0200, Marco Manfredini wrote:
> On Wednesday 12 April 2006 11:39, Stefan Klug wrote:
> > The problem is, that it's rather slow.
> > (Dragging a fullscreen image should be possible at 24fps but I get
> > around 5fps (no exact measurement))
> > I'm only drawing untransformed images at integer positions.
> > The main bottleneck seems to be the transfer of imagedata to the target
> > surface.
> 
> This looks to me like a flaw in the image transfer routine. ARM (and MIPS) 
> implementations usually have very weak support for 8 and 16 bit memory 
> access, which can result in horrible performances for naively coded or ported 
> loops. Do you have the choice to try an image transfer route that does 32 bit 
> memory access only? 

Depending on what Stefan is doing, the "image transfer routine" may well
be the Windows CE native drawing calls (AlphaBlend and so forth).
There's just not enough information yet to get to that level of
speculation.
						Owen




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