GNOME Mutter 3.21.4 Released WIth New Screen Capture API, NVIDIA vRAM Robustness

[phoronix]

Phoronix: GNOME Mutter 3.21.4 Released WIth New Screen Capture API, NVIDIA vRAM Robustness

Various GNOME software components were checked in today in preparation for this week's GNOME 3.21.4 development release...

http://www.phoronix.com/scan.php?page=news_item&px=GNOME-Mutter-3.21.4

[juno]

Screen capture API sounds good to me, but I honestly have no idea.
Wouldn't this make sense to add to Wayland?
I remembered, Martin Graesslin posted something on his blog:

On Wayland the world is different. An application is not able to see the windows of other applications. This means by default Plasma is not able to see what windows exists, the taskmanager would be empty. The only application which knows about the existing windows is the Wayland compositor.

https://blog.martin-graesslin.com/blog/2016/06/a-task-manager-for-the-plasma-wayland-session/

seems like every Wayland compositor would have to provide an interface if somebody want to take a screenshot or capture the screen in motion.
The capturing program would have to implement each of those. So wouldn't it make sense to have it defined in Wayland?

[ElectricPrism]

Screen capture API sounds good to me, but I honestly have no idea.
Wouldn't this make sense to add to Wayland?
I remembered, Martin Graesslin posted something on his blog:

https://blog.martin-graesslin.com/blog/2016/06/a-task-manager-for-the-plasma-wayland-session/

seems like every Wayland compositor would have to provide an interface if somebody want to take a screenshot or capture the screen in motion.
The capturing program would have to implement each of those. So wouldn't it make sense to have it defined in Wayland?

To what are you referring? I'm under the impression that Wayland is a protocol and Mutter is the Gnome implementation of that protocol in the form of a compositor.

[eduperez]

To what are you referring? I'm under the impression that Wayland is a protocol and Mutter is the Gnome implementation of that protocol in the form of a compositor.

Exactly: if there exists the need for a new screen-capture API, it should be added first to the protocol (Wayland) and then implemented in the compositor (Mutter).

This new API implemented in Mutter, is part of the Wayland protocol? are all compositors going to implement the same API? or is it proprietary to Mutter, and other compositors will implement their own different API?

[juno]

To what are you referring? I'm under the impression that Wayland is a protocol and Mutter is the Gnome implementation of that protocol in the form of a compositor.

Exactly: if there exists the need for a new screen-capture API, it should be added first to the protocol (Wayland) and then implemented in the compositor (Mutter).

That's exactly what I meant, but I'm not into the protocol so I thought I'd ask...

Afaiu, this is only for mutter but a little more background info would be great.

[zxy_thf]

Exactly: if there exists the need for a new screen-capture API, it should be added first to the protocol (Wayland) and then implemented in the compositor (Mutter).

This new API implemented in Mutter, is part of the Wayland protocol? are all compositors going to implement the same API? or is it proprietary to Mutter, and other compositors will implement their own different API?

(Correct me if I were wrong).
afaik Wayland protocol has been classified into multiple "tiers" (sorry I don't know the exact term used by the developers), and the core protocol only handles most fundamental things like window creation and even dispatching.
The screenshot API is not the part of the core protocol, and even the official compositor has its own "weston_screenshooter" API.
I think screenshot API has been considered as a DE specific API and DEs are free to create its own one.

[pal666]

This new API implemented in Mutter, is part of the Wayland protocol? are all compositors going to implement the same API? or is it proprietary to Mutter, and other compositors will implement their own different API?

you got it backwards. it is api provided by clutter for use by mutter. mutter does not expose it to wayland clients, mutter just stores screenshots on disk