[Development] About inheriting QBlitterPaintEngine from QGL2PaintEngineEx class

Allan Sandfeld Jensen kde at carewolf.com
Sat Jul 12 19:52:54 CEST 2014

On Thursday 10 July 2014, haithem rahmani wrote:
> Hi,
> When running Qt-5 on top of the directfb qpa plugin,  some benchmarks are
> quite slow.
> (http://smashcat.org/av/canvas_test)
>  I've found that the 2D painting ops are going through the
> QBlitterPaintEngine class
> that is inheriting the QRasterPaintEngine class, which is doing all the
> painting via CPU.
> Qt provides another paintEgine class, QGL2PaintEngineEx, that is doing the
> same paintings via the GPU.
> So I want to know whether is possible to make the QBlitterPaintEngine
> inherit this QGL2PaintEngineEx
> instead of QRasterPaintEngine and got things working correctly or not?
It will probably be easier for you to use Qt 5.4 or cherry-pick 
https://codereview.qt-project.org/88787 . It uses the QOpenGLPaintDevices for 
2D canvases. Note that it only makes some operations faster and other 
especially pixel access slower.

Best regards

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