Wayland Relative Pointer API Progress

[Michal Suchanek]

On 17 April 2015 at 12:52, Hans de Goede <hdegoede at redhat.com> wrote:
> Hi,
>
>
> On 17-04-15 11:47, Michal Suchanek wrote:
>>
>> On 17 April 2015 at 09:11, Pekka Paalanen <ppaalanen at gmail.com> wrote:
>>>
>>> On Fri, 17 Apr 2015 13:43:11 +0900
>>> x414e54 <x414e54 at linux.com> wrote:
>>>
>>>> Thank you for the comments.
>>>> I do have a few counterpoints but I will leave after that.
>>>>
>>>>>
>>>>> Not sure an IR/laser/wii mote pointer should even be considered a
>>>>> "relative" pointer since they operate in absolute coordinates. Given
>>>>> this, there is no "set position" hint to consider. Transmitting
>>>>> acceleramoter data via a "relative pointer" doesn't sound reasonable.
>>>>>
>>>>
>>>> I think this is the issue right here. Pointers are not relative, mice
>>>> are not pointers.
>>>
>>>
>>> What definition of a "pointer" are you using?
>>>
>>> The definition Wayland uses for a wl_pointer is a device that:
>>> - requires a cursor image on screen to be usable
>>> - the physical input is relative, not absolute
>>>
>>> This definition is inspired by mice, and mice have been called pointer
>>> devices, so we picked the well-known name "pointer" for mice-like
>>> devices.
>>>
>>> Specifically, a pointer is *not* a device where you directly point a
>>> location on screen, like a touchscreen for example. For touchscreens,
>>> there is a separate protocol wl_touch.
>>>
>>> For drawing tablets, there will be yet another procotol.
>>>
>>> Joysticks or gamepads fit into none of the above. For the rest of the
>>> conversation, you should probably look up the long gamepad protocol
>>> discussions from the wayland-devel mailing list archives.
>>
>>
>> And how is a joystick different from a trackpoint, exactly?
>>
>> It uses different hardware interface and later different software
>> interface but for no good reason. It's just 2 axis relative input
>> device with buttons. Sure, the big joystick, gamepad directional cap
>> and trackpoint are at a different place of the stick size scale and
>> might have different hardware sensors which should be reflected with
>> different acceleration settings but ultimately it's the same kind of
>> device.
>
>
> Actually joystick analog inputs are absolute not relative. They give a value
> for exactly how much the "stick" has moved from the center.
>
> Except for dpads which are really buttons not relative axis, so joysticks
> really are pretty much not like trackpoints in anyway.
>

Do you mean that the absolute trackpoint excentricity is somehow
translated to relative motion delta in hardware so that it does look
like a mouse although it is in fact a joystick?

Thanks

Michal