Re: [pointerevents] tiltX and tiltY aren't as helpful as just having altitude angle (#274)

> "giving developers what they want" (though, is this backed up by data on developer wants? or purely on "since on this platform there's only this type of data, this is what they want"?)

This is a valuable question! Thanks for asking it. I didn't provide any data.

So let's think about the common apps that would use a stylus. We can ignore everything that only needs the x,y locations (which is probably the majority of apps... because the user is on a stylus and the app just treats it like a regular touch).

Of the "specialised for stylus" apps, I suggest the most common involve painting of some kind. That means they are trying to emulate a brush or nib, so the important inputs are:

- the pressure at the tip
- the orientation of the nib around the surface
- the angle between the surface and the stylus

i.e. pressure, azimuth and altitude

Giving them tiltX and tiltY just means they have to do calculations.

So what apps would actually want tiltX and tiltY? I guess some kind of simulation (e.g. surgery). But even then, if they are trying to represent a physical object, then the vectors they are interested in are better represented by the azimuth and altitude.

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Received on Monday, 28 January 2019 23:47:18 UTC