rust-windowing
Touch input contact size
I noticed that it has been really helpful to determine the contact size of a touch input by using PointerEvent.width/height to improve accuracy.
I'm not sure about other platforms, but a quick look at the Windows API revealed POINTER_TOUCH_INFO.rcContact.
In any case, like force, this could be wrapped in an Option.
Wayland should have it as well https://wayland.app/protocols/wayland#wl_touch:event:shape
The thing is that device may not support reporting the shape of the input, so I'd assume it must be an Option.
Also, it's an ellipse and not a rectangle on Wayland, so it's a bit weird here.
After some digging into this lately, all these APIs are meant to represent ellipsis.
- Web should move all
WindowEvent::Touchto use touch events instead of pointer events. These expose much richer information (Touch.radiusX/YandTouch.rotationAngle) and align much more with other backends. They also clearly state that the contact points are ellipsis. - Wayland has
wl_touch::shapeandwl_touch::orientationdescribing the ellipsis. - Windows has
POINTER_TOUCH_INFO.rcContactandPOINTER_TOUCH_INFO.orientation, which are supposed to represent an ellipsis as well, but is just not documented as such. Chromium treats this information as an ellipsis as well.