ChromeOS Mirrored AND Extended Displays

[Bill_Gibson]

Our K-12 teaching staff using Windows OS based laptops frequently use a multi-screen configuration where the laptop display and a connected projector are mirrored while a stand-alone monitor on their desk has an extended desktop. This configuration enables them to face the classroom of students from their desk, easily seeing the screen content that the students are being shown while providing a private screen to address classroom management/administrative tasks.

Using this same projector/monitor hardware, Chrome OS currently only supports extended desktop across all three displays or mirroring the display across all three displays. This is a limitation that may prevent us from moving to CrOS devices, or would likely lead to our teaching staff abandoning the desk based display component reducing their effectiveness.

I opened a support case and they referenced a feature request case number of 884825

[SteveHarmon]

I did not realize this was the case with Chrome OS! Great information, Bill!

One solution that I did think of is that you could wire the external, extended display and then wirelessly cast the student view to the projector. Of course, wirelessly casting often has issues (especially with video), but it would allow the Chrome OS to customize the view similar to the Windows OS version.

Another idea would be to use an HDMI splitter which would allow the external monitor and display to be mirrors of each other and extended from the Chrome OS device.

Ideally, though, I agree with you that it would be great if Chrome OS could handle all of that internally.

[Kim_Nilsson]

A simple HDMI-splitter will solve that.

If you are able to choose which devices to be mirrored and which to be extended, then that is actually a Windows only feature.

MacOS can't control this, even though it's the exact result if connecting through it with a single cable. Only if you connect all external displays directly to the Mac are you able to make them all separate, which is normally what people want.

Interesting that your use case is exactly the opposite of what people with two external displays usually want. Totally understand it, as it is a special case for education.

[jhandler]

Yes this is a very specific educational use case.    The external monitor mirrors the projector allowing the teacher to see and interact with the projector display while using their built-in Chromebook screen for other administrative tasks needed while doing lessons.

[Bill_Gibson]

If anyone is able to upvote/comment on this on the Chromium/Monorail platform it would be appreciated
https://issues.chromium.org/issues/40938715

[claycodes]

Hey all, looking into the feasibility of this. A few questions:

• Would you be OK with Chromebook Plus only having this capability? Mirroring needs the extra processing so this may be a caveat. 
• Looking at the ability to mirror the Laptop screen to one display and have the other display as extended to take advantage of touch screens. Is this acceptable?
• Chromeboxes may not be considered for this. Any thoughts on this? Noting that Kiosk apps do this through APIs so a chromebox used for Kiosk would have a different method. 

[Kim_Nilsson]

Hi @claycodes 

Responding to your questions in order, hoping that is clear.

Restricting it to Chromebook Plus should mean that it'll only be for teachers, as I don't foresee student devices being purchased with a Plus stamp/hardware. When I say should, I also mean that no organisation should be buying non-plus CBs to teachers. Which in turn should mean that it's not OK to hike up the prices on Plus machines to the moon, or nobody will buy them.

Hmm, isn't this exactly what is requested? Ah, no, I see it now. It's not exactly as requested, but in my opinion, it is conceptually the same, as it solves the problem. @Bill_Gibson what do you think?

A Chromebox doesn't have its own screen, but the concept is still the same. The teacher wants to be able to connect two "local" screens where only one is mirrored to a larger remote screen. In my mind, it doesn't really matter if one of the "local" screens is a built-in screen (like on a Chromebook) or an external screen. Currently it's not possible.

[MattDPenn]

It would mildly disappoint me if it was restricted to Chromebook Plus. Partially because we've bought new chromeboxes just before the Plus designation came out though I haven't checked if the chromebox model will retroactively get Plus software. Does mirroring actually take more processing than extending? I would have thought it would be the opposite.

On the note of touch screens are more settings going to become available for this? I'm running into an issue with Epson Brightlink projectors, which are essentially touch screens, where the touch input isn't always registering to the correct screen when running in extended. When I go into settings I haven't found where you specify what screen you want touch input to affect. 

I would hope chromeboxes would be included. Not just my district but it seems like other school districts are looking at chromeboxes to replace in classroom equipment and it would help to keep features between chromebooks and chromeboxes the same. In my situation I have 2-3 screens hooked up to my teacher's chromeboxes.

[Bill_Gibson]

Speaking specifically to your questions and our deployment:

• Yes. Our staff deployment will be with Plus devices and this specific feature request is to support in-classroom management so will not affect student devices.
• Yes. Similar to @MattDPenn many of our classrooms (specifically K-8) use Epson Brightlink Interactive  projectors.
• We only use Chromeboxes to support digital signage with Chrome Sign Builder, not in the classroom setting.

Thanks for looking into this FR!

[YERKO]

Saludos @Bill_Gibson como sugiere @SteveHarmon la solución mas practica y considerando una posible migración a equipos Chromebooks (en nuestro colegio no contamos con ninguno), sería incluir en el presupuesto un divisor HDMI o VGA dependiendo de los proyectores con los que cuente su colegio y así poder resolver el problema, por lo general en el mercado dichos dispositivos externos son económicos y duraderos, siempre y cuando se utilicen correctamente.

Felicito a tu unidad educativa por el dominio de los docentes de trabajar con tres pantallas y con información y monitoreo en simultáneo, en mi colegio a algunos docentes el equipo está en escritorio extendido (en windows) y se asustan y dicen que el proyector está malo porque no muestra lo que ellos ven en su pantalla 😉

[Bill_Gibson]

Hi @YERKO ,
We are moving forward with this deployment and have chosen to purchase HDMI splitters. Unfortunately, our desktop monitors were all Display Port, so these need to be replaced as well. (We found that sourcing an economical DP and HDMI splitter is quite hard).

Initial adoption of extended/mirrored desktops was slow but those that have switched over to use it are able to access information more easily.