Re: [mediacapture-image] Add pan and tilt constraints

> Roll can easily be added, in my experience it isn't commonly available in consumer webcams so I didn't add it at this time. Most webcams in laptops and phones aren't going to have support for pan/tilt/roll at all, but I know Logitech brand webcams have support for pan/tilt, but not roll.

I'm not sure whether W3C APIs should be tailored for particular brand or type of device.

> You'll have to expand on that a bit, I don't quite follow.

When object is rotated in 3D space, order of rotations can affect end result http://quaternions.online/ , maybe I'm wrong :smiley: 

> I guarantee that's going to mess with people's code. Anyone not familiar with the behavior of floats wouldn't have that kind of situation occur to them, and so they wouldn't check.

I'm think it is not related to arcseconds or degrees, it is generic rounding problem. Spec doesn't say what happens when step has decimal places e.g., 1.89.

@yellowdoge Maybe specification could add note about rounding problem or introduce different `MediaSettingsRange` interfaces.

**For example:**
color temperature, iso, brightness, contrast, saturation, sharpness, zoom **=>** `unsigned long long`
focus, exposure comp **=>** `unrestricted double` (focus can be +Infinity)
tilt, pan, roll **=>** `long` (+-180deg)

@dsanders11 my personal opinion is that pan, tilt and roll are niche features and not directly related to photo / video capture capabilities. Those are the features of camera accesoires: motorized heads, 3-axis gimbals, conference webcam or security IP cams chassis. Looks like UVC and Windows APIs have those features for some legacy reasons, I'm not sure whether new specs should replicate same pattern.

Also, Windows is a good example of what not to do. Half of the methods [get / set arcseconds]( https://msdn.microsoft.com/en-us/library/windows/desktop/dd376341(v=vs.85).aspx), while other half [uses degrees](https://msdn.microsoft.com/en-us/library/windows/desktop/dd376347(v=vs.85).aspx).

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Received on Friday, 16 June 2017 14:27:48 UTC