[webkit-qt] GraphicsContext and Canvas

Lars Knoll lars.knoll at nokia.com
Thu Feb 4 23:44:08 PST 2010

On Thursday 04 February 2010 05:05:43 pm Rosenthal Noam (Nokia-D-
Qt/RedwoodCity) wrote:
> >-----Original Message-----
> >From: Knoll Lars (Nokia-D-Qt/Oslo)
> >
> >One thing worth considering is IMO to only use a QImage to
> >render the canvas content into, and avoid any
> >caching/conversion magic between images and pixmaps. We don't
> >get any HW acceleration for drawing with this, but it might
> >still be faster and easier than doing possible conversions
> >back and forth.
> I don't see why we would need to convert back to an image at all if the
>  user doesn't call getImageBuffer. Many times all we do with canvas is
>  transform; drawImage; fillRect; transform; drawImage; etc. In that case,
>  which is much more common than getting the image buffer or setting pixels
>  directly, HW acceleration is crucial.

The best answer unfortunately depends on the HW we're running on. On the N900 
for example, using tiled rendering, we are probably fastest if we use raster 
for rendering into images and then tile these using OpenGL. On another device 
doing it all in HW might be better.


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