Improve touch-based visualization

[Venerons]

Improve touch-based visualization.

Currently a touch-point create a blurry random-colored circle. This circle is not easy to see as it is under the fingers, and doesn't match the sharp style of the rest of the app.

The goal is to change this to create a circonference outer the finger, without any blur and with vibrant colors. This way the touch point is more visible and match better the app style.