Mirrored content (All monitors in pos 0,0)

[sergioperez]

Scenario

• I have a game running full-screen in a "main monitor" (1366x768)
• I plug-in an "additional display" on the second HDMI port, for example, an HDMI capture card

Expectations

It would be interesting that, in this scenario, the "secondary output" is set to the same resolution as the "main monitor" (1366x768), and also positioned at (0,0).

In this way, the same content would be visible in both screens.

Ideas

Do you think it would make sense to have new cage modes? As:

• -m custom -> Runs a script/command when the layout changes. Hence, an user could develop custom behaviors using bash and wlr-randr
• -m overlap -> Overlap all outputs (Maybe setting one output as the "main one")

At the moment, I am trying to resolve this scenario with some maybe not ideal scripts to achieve this in (my repo).

I assume that the output names will not be consistent in this scenario, as the image will be used in different systems

[emersion]

Related: https://gitlab.freedesktop.org/wlroots/wlr-protocols/-/issues/101

We'd need a way to set the source box of outputs in wlroots' scene-graph.

[joggee-fr]

Hi @sergioperez,
One thing I have done before to solve an analogue issue is writing a custom Wayland client mainly based on wlr-output-management protocol. The client simply waits for an output to appear and sets its position to (0,0), plus setting the mode to the same than the main output. Of course, this imposes some constraints.
Kind of dynamic $ wlr-randr --output HDMI-A-1 --pos 0,0 --mode 1920x1080.

[emersion]

If resolutions match, kanshi should be able to do this.

[n3rdopolis]

What about mismatched screens? Like a 1920x1080 and a 2160x1440 for instance? Could it be possible to just go with the smaller resolution so that it's just a 1920x1080 rectangle on the 2160x1400?

[emersion]

If the aspect-ratio is the same, the scale can be adjusted to match. If the aspect-ratio is different, this would be needed: https://gitlab.freedesktop.org/wlroots/wlr-protocols/-/merge_requests/116

[n3rdopolis]

oh cool, scaling would be even better