[Qt-interest] Why doesn't the X11 paint engine support QPaintEngine::PixmapTransform?

[Michael T]

Dear List,

I hope that this is the right place to ask this, as ideally one of the developers working on that code would be best placed to answer.  I noticed that when using the Qt X11 paint engine backend (src/gui/painting/qpaintengine_x11.cpp), if one tries to do a drawPixmap operation with a transformation more complex than a simple translation, the pixmap will be copied over to a QImage, the transformation done there in software, and the result copied back to the X server.  This is even if XRENDER is in use.  It seems to me that one could do the transformation on the server at painting time (in the XRENDER case of course) using XRenderSetPictureTransrform(3) to rather increase the efficiency of the operation.  I have trouble believing though that the developers, who surely understand XRENDER much better than I do, didn't think of that, so I am wondering why they chose not to do this.

Thanks in advance for any answer.

Regards,

Michael
 		 	   		  
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