I have 2 QML Profiler questions.  I am profiling a simple Knob widget which is 
made out of an Image and a MouseArea, with some Javscript to control the 
rotation property of the Image.

When I profile the Knob in QML Profiler, I see that the Knob is efficient, in 
that there are no Paint events.   This must mean that when the Knob is created, 
the Knob png is sent to the GPU, and after that, the rotation is simply 
controlled by a rotation command sent to the GPU for that Image.  Hopefully, I 
understand that correctly.

Question 1:  Is the rotation command that is sent to the GPU considered to be a 
'compositing event', and if so, will QML Profiler show compositing activity 
separately, as in Chrome Dev Tools in Chrome?

I also discovered that in Qt 5.1, if you manipulate opacity on an Item during 
onPressed and onReleased mouse events, Paint events occur for that Item even 
when the Item has visible: false.  I would think that visible property would 
supersede opacity to ensure most efficient draw.

Question 2: Should I report this as a bug?


I was going to try and test these on Qt 5.2 Beta, because I know the scene 
graph renderer has been reworked, but I'm not able to run the QML Profiler in 
Qt 5.2 Beta like I can in Qt Creator 2.7.2/Qt 5.1.  I entered a bug about that 
already.

- VStevenP


_______________________________________________
Interest mailing list
Interest@qt-project.org
http://lists.qt-project.org/mailman/listinfo/interest

Reply via email to