[Development] Extending touch semantic information and Qt backends

[Александр Волков]

Hi, Ariel.

11.02.2016 04:13, Ariel Molina пишет:
> - Multiple touch devs/layers and Person tagged touches. Can be easily 
> added by extending QWindowSystemInterface::TouchPoint with a device 
> identification, like device(). This will also work for TUIO.
There is QTouchEvent::device(). Isn't it enough?

> - Area & rotation. There is TouchPoint::area() and ::pressure() but 
> currently there is no support for ::angle(). Angle can be zero when 
> not supported.
Angle is not enough, because for compatibility with older apps 
TouchPoint::rect() should be as close as possible to the rotated rect.
See https://codereview.qt-project.org/#/c/114238/
In other words it should be a projection of the rotated rect, so you 
should introduce a separate method to get the rotated rect.

> - Unique identification. On research and advanced interactive surfaces 
> the usage of "markers" [3] is quite common. This is just a code 
> extracted either visually or by other mechanisms which is passed along 
> the touch information. I conjunction with area, rotation and uuid this 
> paves the way for very rich interaction.
How does it differ from TouchPoint::id()?

BR,
Alexander.