Re: [pointerevents] Should pressure be set to 1 or .5 on devices that don't report it?

> InputDeviceCapabilities would be useful (and should have all 
capabilities as @patrickhlauke suggests) - but my guess is with good 
defaults less than 5% of developers would use it. If I can pick up 
Tilt and use it as is, supported or not (no tilt support means the 
stylus is reported as vertical), then I won't look at tiltSupported to
 do something special.

> With some defaults, InputDeviceCapabilities is required:

> opacity = pressure;
> if (! InputDeviceCapabilities.pressureSupported) then
> opacity *= 2.0; // required to reach 100% opacity on non-pressure 
styli
> endif

IMHO this argument is compelling.  We should define a default value 
that best matches the typical usage. If pressure is often mapped to 
opacity and pressure-sensitive stylus users already know to press hard
 to get an opaque line, then a default of '1' makes sense.  In 
contrast, if pressure is more often mapped to line width and 
pressure-sensitive stylus users know to use a moderate touch to get a 
reasonable middle-width line then '0.5' is probably the better 
default.  I have no data on this but trust dfleck@'s judgement (Wacom 
is probably in the best position to say what's most typical).

Note that both 
[Android](https://developer.android.com/reference/android/view/MotionEvent.html#AXIS_PRESSURE)
 and 
[iOS](https://developer.apple.com/reference/uikit/uitouch/1618110-force)
 use 1.0 as the "normal pressure value" (and so the appropriate 
default).  If Windows is the odd OS out, then I'd prefer to match the 
majority OS behavior and rely on some windows-specific code to map 
between the OS and PointerEvents.


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Received on Wednesday, 28 September 2016 16:39:53 UTC