Thank you very much for your answer!
I must use QGraphicsProxyWidget because i need to flip the application of 180°! I'm in an embedded system with petalinux where i can't use a window system like x11 and so the rotation has to take place at a higher level (in the qt code)...
The previous code with the if statement works quite well...sometimes it doesn't receive the multitouch but it's decent! I just don't understand why if i pass the TouchBegin to QGraphicsVIew::viewportEvent(event) no TouchUpdate arrives...instead if i return true TouchUpdate and End arrive...

@SGaist said:

Very interesting and detailed explanation, thanks !

I wonder wether Qt should automatically detect or not your multiple devices… That's a question you should bring to either the interest mailing list or the #qt IRC channel. You'll find there Qt's developers/maintainers (this forum is more user oriented)

Ah, thanks for the info! I will check out the mailing list and the IRC channel!

For my purposes, auto-detect is probably not necessary, but I am unsure about "the general case". Anyway, it would be interesting to get the developers input on why there is a difference in auto-detect behavior depending on driver capabilities, and whether that is intentional or a bug.

Thanks!

Cheers,

/johan

@winkler3523 Good find. But it seems to be there from ages :) Vote it up.