- From: dfleck via GitHub <sysbot+gh@w3.org>
- Date: Mon, 28 Jan 2019 22:09:35 +0000
- To: public-pointer-events@w3.org
There are two common APIs: xTilt, yTilt, and twist or altitude (angle between stylus and surface), azimuth (“compass” direction of tilt), and twist twist is axial rotation of the stylus, and is the least supported (it usually requires an additional electrode or coil). Twist is important for non-symmetrical brushes (think chisel tip marker where moving with the stylus vertical could result in a narrow line, or a wider line when there is a 90 degree twist) Due to the detection method (in most cases a series of X and Y electrodes or coils) what is natively measured is xTilt and yTilt. This is often converted to azimuth and altitude with simple trig. Twist has nothing to do with this transformation. Depending on the brush, both altitude and azimuth can be important. Take an airbrush for example. When vertical (altitude = 90 degrees) the brush is circular and azimuth doesn't matter. However it becomes somewhat oval and directional (spraying away from the tip) when altitude isn't 90 degrees. When the stylus is tilted, the direction of the oval spray depends on the azimuth (but does not depend on twist with a round nozzle). -- GitHub Notification of comment by dfleck Please view or discuss this issue at https://github.com/w3c/pointerevents/issues/274#issuecomment-458321700 using your GitHub account
Received on Monday, 28 January 2019 22:09:36 UTC