> On Apr 6, 2017, at 7:57 PM, Ch'Gans <chg...@gna.org> wrote: > > On 7 April 2017 at 14:38, Patrick Stinson <patrickk...@gmail.com> wrote: >> I am implementing a pan and zoom on pinch via raw touch events and am >> finding setTransform() to be very slow, even with an empty scene. The touch >> events are backed up in a queue by slow synchronous calls to >> QGraphicsView.setTransform(). > > If it's slow with an empty scene, then you have a problem that has > nothing to do with QTransform. Maybe you have a cascade of events that > bounce on each other until it stabilise... > Maybe your synchronous calls are too frequent. I would advise to use > the animation framework to do this sort of things.
This is possible. I will check further. > > Whats your environment, which HW, which OS, which Qt, … I am using Qt-5.8.1 and PyQt-5.8.1, latest sierra with latest MacBook pro > >> >> Without stripping down my code into a runnable example, is setTransform >> considered to be too slow for 60Hz frame-rate updates from touch events? If >> so, is there a better way to smoothly zoom and pan the graphics view? > > Use the animation framework. no need for a queue mechanism, should > work without any problems unless you hardware is not powerful enough. > How would one animate the transform without a "transform" property? Or am I missing something? (I’ve been away from qt for a while - since before the animation framework) > Chris > >> >> Thanks! >> -P >> _______________________________________________ >> Interest mailing list >> Interest@qt-project.org >> http://lists.qt-project.org/mailman/listinfo/interest _______________________________________________ Interest mailing list Interest@qt-project.org http://lists.qt-project.org/mailman/listinfo/interest
