I have a Qt5 application using Qwt Library for plotting a few traces, with graphic zoom, and some other simple Qt widgets, like QLabel, QPushButton, QScrollBar, QFrame and the like.
The application is running on Linux.
Linux kernel is 3.10.17.
Distribution is Ubuntu 14.04.4 LTS (trusty).
Qt version is 5.2.1.
I was trying to run the application specifying the platform eglfs (which should work directly on Linux framebuffer, as far as I could understand) instead of the default xcb (which needs the X server).
However I could not get it working (problem is described in this post: "EGL Error : could not create the EGL surface: error 0x300b" on i.MX6 when running Qt5 application with -platform eglfs).
My question is:
in case I succeed, would I have a significant performance improvement with eglfs with respect to xcb, in terms of CPU load?
I didn't see huge difference between eglfs or xcb platform of Qt, even xcb is smoother some times. for example mouse movements are very smooth in xcb, not in eglfs. But there will be a huge improvement if you use QGlPainter instead of QPainter and accordingly use QGlWidget instead of QWidget.
Also QtQuick2 works fine with eglfs, its very smooth and high quality in our IMX6-Rex board.