multi-touch-dev team mailing list archive

[Duncan McGreggor <duncan.mcgreggor@xxxxxxxxxxxxx>]

On 02/23/2011 11:42 AM, Chase Douglas wrote:
> On 02/23/2011 01:26 PM, Ping Cheng wrote:
>> On Wed, Feb 23, 2011 at 9:36 AM, Duncan McGreggor
>> <duncan.mcgreggor@xxxxxxxxxxxxx <mailto:duncan.mcgreggor@xxxxxxxxxxxxx>>
>> wrote:
>>
>>
>>     -------- Original Message --------
>>     Subject: Re: touch input rotation
>>     Date: Tue, 29 Jun 2010 07:43:56 -0700
>>     From: Kees Cook <kees.cook@xxxxxxxxxxxxx
>>     <mailto:kees.cook@xxxxxxxxxxxxx>>
>>     Organization: Canonical
>>     To: Alberto Milone <alberto.milone@xxxxxxxxxxxxx
>>     <mailto:alberto.milone@xxxxxxxxxxxxx>>
>>     CC: Federico Mena Quintero <federico@xxxxxxxxxx
>>     <mailto:federico@xxxxxxxxxx>>,        Bryce
>>     Harrington <bryce@xxxxxxxxxxxxx <mailto:bryce@xxxxxxxxxxxxx>>,      
>>      Chase Douglas
>>     <chase.douglas@xxxxxxxxxxxxx <mailto:chase.douglas@xxxxxxxxxxxxx>>,
>>            "Duncan M. McGreggor"
>>     <duncan.mcgreggor@xxxxxxxxxxxxx
>>     <mailto:duncan.mcgreggor@xxxxxxxxxxxxx>>,        Rick Spencer
>>     <rick.spencer@xxxxxxxxxxxxx <mailto:rick.spencer@xxxxxxxxxxxxx>>,  
>>          Rafi Rubin <rafi@xxxxxxxxxxxxxx <mailto:rafi@xxxxxxxxxxxxxx>>
>>
>>     Hi Alberto,
>>
>>     On Tue, Jun 29, 2010 at 04:20:56PM +0200, Alberto Milone wrote:
>>     > On 28 June 2010 20:14, Kees Cook <kees.cook@xxxxxxxxxxxxx
>>     <mailto:kees.cook@xxxxxxxxxxxxx>> wrote:
>>     > > I saw your touch input rotation work[1].  I was looking at this too,
>>     > > and I think it needs to be done more generally (in gnome-desktop
>>     rather
>>     > > than g-s-d), and with XInput (rather than calling out to xsetwacom).
>>
>>  
>> I agree with Alberto on this point. Using something generic, like
>> Xinput, rather than vendor/project-specific helps the community in the
>> long term.
> 
> There's a few steps to handle autorotation:
> 
> 1. Detect rotation
>   - Listen for lid switch events?
>   - Listen for accelerometer events?
> 2. Rotate screen using XRandR
> 3. Rotate touchscreen input devices
>   - X server has a "Coordinate Transformation Matrix" property for each
> device, use it to perform input coordinate transformation
> 
> I have a feeling that step 1 will be hardest, because I don't think
> there's any standard way to determine device orientation. We probably
> need some system-wide service to watch for these types of events and
> handle them appropriately.
> 
> Step 2 is already performed by gnome-settings-daemon (g-s-d) when you
> connect or disconnect a monitor. I would think it could be extended for
> this purpose.
> 
> For step 3 we need a mapping from touchscreens to Xinerama screens. We
> don't currently have any tool to do this. If you have a touchscreen on
> one monitor, and you plug in another, you will need to set the transform
> matrix manually or else your touchscreen will operate over the entire X
> screen! I don't know where this mapping should live, but if g-s-d could
> get to it then it could also handle this too.
> 
>> The good news is that kernel input subsystem has added (maybe not in the
>> tree yet, Henrik should be able to tell us more) a new set of ioctl so
>> we can retrieve the device types directly from the kernel. With this new
>> ioctl, generic "device self-identification" is available.
> 
> Yep, this will be very useful for setting up devices. In XI 2.1, devices
> will have a "mode" that tells us whether it's being used as a
> touchscreen or a touchpad or something else. g-s-d could look for these
> devices to map them to xinerama displays.
> 
> I have a feeling we should revisit this at UDS to map out how this
> should be tackled. There's a good chunk of development here, but it
> shouldn't be too difficult with the apis and interfaces we have already.

Agreed :-) In fact, I agreed so much, the first uTouch (and maybe DX
Team?) blueprint has been created for UDS O in Budapest:

https://blueprints.launchpad.net/ubuntu/+spec/dx-o-auto-rotate

Already looking forward to more good discussions :-)

d