Hello fellow developers.

I am building a google maps client using Qt and QGLWidget, mostly because I'm sick of slow performance maps applications.

I am getting some slowdowns while dragging the map around and I have reasons to believe that it's either because the CPU does the rendering or something makes the touchscreen pull readings slower than the display.

About the CPU rendering, when launching the application without any params, the main drawing routine never exceeds 5000 nano seconds (5 milliseconds). Assuming a framerate of 60FPS, that is perfectly okay (60FPS = 16.67ms draw time).
Now, I believe that is the CPU because when I launch my application with "-graphicssystem opengl" I get a weird and cryptic error - "QX11GLPixmapData is *NOT* being used", so I'm assuming GL rendering fails for some reason.

So even if OGL ES rendering is disabled, frame render speed should be enough for a smooth display - unless the touchscreen makes less reads than the display does updates.

Please feel free to correct my assumptions, I'm only here to learn - after all, this IS my first Qt/N900 application.

For those who want to experiment, or just interested, feel free to browse the source.

I haven't tried this on device yet (desktop only), but one suggestion for something to try... if you draw a smaller grid of tiles, does your visible performance appear to increase?

Actually, one would think so, but even with one tile, performance seems (visually) the same.

Feel free to modify the code, get rid of the loop and try it for yourself.