FW: xrandr and xwayland

[David Deyo]

From: Carsten Haitzler<mailto:raster at rasterman.com>
Sent: Tuesday, August 3, 2021 9:38 AM
To: David Deyo<mailto:ddeyo at tireprofiles.com>
Cc: wayland-devel at lists.freedesktop.org<mailto:wayland-devel at lists.freedesktop.org>
Subject: Re: FW: xrandr and xwayland

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On Tue, 3 Aug 2021 13:40:25 +0000 David Deyo <ddeyo at tireprofiles.com> said:

> From: Carsten Haitzler<mailto:raster at rasterman.com>
> Sent: Tuesday, August 3, 2021 8:13 AM
> To: David Deyo<mailto:ddeyo at tireprofiles.com>
> Cc:
> wayland-devel at lists.freedesktop.org<mailto:wayland-devel at lists.freedesktop.org>
> Subject: Re: FW: xrandr and xwayland
>
> CAUTION: This email originated from outside of the organization. Do not click
> links or open attachments unless you recognize the sender and know the
> content is safe.
>
>
> On Tue, 3 Aug 2021 13:04:11 +0000 David Deyo <ddeyo at tireprofiles.com> said:
>
> >
> >
> > From: David Deyo<mailto:ddeyo at tireprofiles.com>
> > Sent: Monday, August 2, 2021 3:53 PM
> > To: Pekka Paalanen<mailto:ppaalanen at gmail.com>
> > Subject: RE: xrandr and xwayland
> >
> > On Fri, 30 Jul 2021 23:30:38 +0100
> > Carsten Haitzler <raster at rasterman.com> wrote:
> >
> > > On Fri, 30 Jul 2021 16:28:02 +0000 David Deyo <ddeyo at tireprofiles.com>
> > > said:
> > >
> > > No - this is up to the compositor itself to do in its own internal ways.
> > > Far too many abuses have happened over the years with xrandr available to
> > > any client anywhere. While in theory a wayland compositor could create an
> > > extension that works like xrandr, it'd be problematic to make it
> > > general-access like xrandr.
> >
> > >>>Indeed.
> >
> > > >
> > > > Hello  everyone,
> > > >
> > > > I need to rotate  my screen 90 degrees and back to normal in xwayland on
> > > > an iMX8 running gatesgarth distro.
> >
> > >>>Maybe you could explain your top-level use case for this, and the
> > >>>general system architecture (which relevant programs are running and
> > >>>what their responsibilities are)?
> >
> > Distro:
> > I am working on a product that our company is creating.  It uses an imx8 som
> > from Boundary.  The system is not a normal desktop. The DISTRO is created by
> > yocto using the gatesgarth branch.  Just recently we were notified that
> > Xwayland was working, so I don’t expect we will be removing it just yet.
> >
> >
> > Use case:
> > We will have a kiosk-looking desktop.  Some of our pages will have the
> > option for the end user to enter text from an on-screen keyboard. Since our
> > display will be so small (68.04mm (2.68") x 120.96mm (4.76")), we will have
> > to turn our unit sideways to make the keyboard fit.  We have already done
> > this on a smaller screen (1.0). On our 1.0 product, we used Segger as our
> > graphics library.  Compared to Android, and the like, it seems like
> > rotating the screen would be a standard capability.
> >
> > I believe our compositor (Weston) can do it, transform=90, but to use this
> > method, it has to be restarted; causing our gui app to crash and lose all
> > entered data. The client probably needs to drive the orientation.
> > Considering our gui will likely be in python3/tkinter, I will need some way
> > create a page and rotate the display.
> >
> > I am somewhat limited by the packages available to me in my distro.
>
> > > > >The right way here is to modify Weston to do on-the-fly rotation
> > > > >without a restart. You also will want a custom protocol from client to
> > > > >compositor to indicate when a client surface wants rotation. This way
> > > > >the compositor can correctly rotate the client content and any other
> > > > >on-screen content at the time
> > > > > (e.g. keyboard) when that client surface is the active visible one
> > > > > (as a kiosk
> > > > >style only one will be active/visible at a time - except for things
> > > > >like keyboard etc.). When you switch which surface is the active one
> > > > >then the compositor can re-evaluate how to draw on the screen based on
> > > > >what that client has requested rotation-wise.
> Thank you,
> A custom protocol makes sense.
>
>   1.   What’s the best way to communicate with Weston, socket, message,
> function  call?

> > > > > >Wayland protocol. You can create extensions as XML files and use
> > > > > >wayland-scanner to generate C code to handle that protocol.
Ok, thanks.

>   2.  How would Weston actually rotate the display, in particular on the fly?
> In the Weston documentation, it states that a super-kbd key and middle mouse
> button should rotate the display (if supported). I’d like to find where that
> is, as well.

> > > > > >Any number of ways. It could modify the KMS device properties for that output
> > > > > >to rotate. It could render rotated (in GL transform the triangle coordinates
> > > > > >when rendering) or in software render the pixels rotated as you read and write
> > > > > >them from one place to another (various algorithms can be used here). Weston
> > > > > >already can do these so it's just a matter of gluing together the code with
> > > > > >your protocol and some logic.
Excellent, along with rotation, I will also need to keep touch working correctly.
Does that decide any of the ways over the other?
-dwd

> -dwd
> --
> ------------- Codito, ergo sum - "I code, therefore I am" --------------
> Carsten Haitzler - raster at rasterman.com
>


--
------------- Codito, ergo sum - "I code, therefore I am" --------------
Carsten Haitzler - raster at rasterman.com

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