Philippe wrote: >>> 2) Using QPainter directly (OSX api) to draw is dead slow, 550% slower >>> that drawing to QImage. >>> I am wondering if there is any interest to this? Is it even normal? >> There are cases where CoreGraphics does better than the usecase you >> provided, but we are in general not happy with the performance we get >> from it. This is why we are opening up the option for switching to use >> different graphics backends on both OSX and X11. You can run >> applications with -graphicssystem raster (or even configure Qt with it >> to have enabled for all apps). You can also try with the highly >> experimental -graphicssystem opengl, but it probably won't look so good ;) > > The Qt 4.5 doc says: by default the backends is "Software Rasterizer" for > Windows. > > But by tracing with the debugger, in API QGraphicsSystemFactory::create, > the default engine is in fact "native", not "raster".
I see that that can be confusing ;) "native" means that it uses whatever is default on the system. On windows this is the software rasterizer. > In all cases, I see no difference of speed. In earlier Qt version, native was > faster under Windows. Since 4.0, Qt has been using the software rasterizer which is the exact same as is used on QImage. Assuming you have the same image format on the backingstore as you have on the image you are drawing you will get the exact same speed and you always did. The use of -graphicssystem raster only offers a potential benefit for Mac OS X and X11. - Gunnar _______________________________________________ Qt4-preview-feedback mailing list [email protected] http://lists.trolltech.com/mailman/listinfo/qt4-preview-feedback
