[Orientation] Allow applications to specify the orientations supported

[Gerry Boland]

Currently unity8 shell has a partial implementation of orientation support. It trusts applications to rotate their own contents, if they want to. The shell doesn't reposition the panel (at the top) though, so a landscape app still has a portrait panel on the side.

For proper orientation support in the shell, shell needs to know if the application wants to rotate its contents or not. To animate correctly, we really need shell to be responsible for rotating the app surface, not the app itself.

Therefore an application needs to tell shell what orientations it supports, so shell can respect its wishes.

A hint in the desktop file may be sufficient.

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Desired UX

As described above. Application should be able to tell the system its possible orientations so that the shell can handle the actual rotation accordingly.

[Michał Sawicz (saviq)]

> A hint in the desktop file may be sufficient.

Nope, it needs to be a surface property. Apps need to be able to dynamically change their orientation preference.

What's more, as discussed before, some apps will still want to rotate themselves (like camera, probably some games). The panel still needs to change position in that case, and we may say we only support this if app is fullscreen.

All in all, I believe this needs design exploration.

[Zsombor Egri (zsombi)]

From toolkit point of view, we need an API from QtMir to drive the app orientation, and orientation flags in MainView.

[Sylvain Becker (sylvain-becker)]

Hello,

I am the one who talks/asks Gerry about this feature.

My applications/games require a specific orientation : some require Landscape, others Portrait. So they need a way to request/lock this kind of configuration. The file ".desktop" would be really convenient to use (though it may not be dynamic as Michal said).

If you make it an API, please note this is not specific to QtMir. My applications don't use QT at all.
They are directly using MIR Client + OpenGL.

Cheers,

Sylvain

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Gerry Boland (gerboland)]

For iteration 1, the SDK team team agreed that setting the supported orientation in a desktop file hint is sufficient. Should we need more granularity, we can create an API for applications to set it themselves. But the lack of an existing API in Qt's QScreen class means that API would be custom to the UITK.

Awaiting UX decision

[Gerry Boland (gerboland)]

Just found https://bugs.launchpad.net/mir/+bug/1382209 "[Enhancement] Add an API to lock surface orientation"
so a UX decision would help clarify what we really need

[XiaoGuo, Liu (liu-xiao-guo)]

For some of the application, we need to have a fixed orientation at the start-up. For example, a car racing game may expect to have a the landscape orientation instead of the portrait, and it should be fixed instead of being automatically changing the orientation when a phone's orientaton is changed.

[Albert Astals Cid (aacid)]

unity8 waiting for design -> Incomplete

[Laurie Bradshaw (lauriebradshaw)]

Seems mir has the necessary support with mir_surface_set_preferred_orientation, which confusingly doesn't do anything at the moment, as the shell isn't honouring it.

I'm currently providing orientation support in neverball and tuxracer by rotating the whole scene and touch input to the user preference, and locking to an arbitrary orientation using the desktop file parameter to prevent automatic rotation interfering with the gameplay.

It'd be much better if the mir surface flag was honoured so the panel and gesture edges would also be rotated in order to maintain consistency with other applications.

[Daniel d'Andrada (dandrader)]

@Laurie

This bug is about enabling apps to tell the shell what orientations it supports (through that desktop file parameter). The shell deciding when to rotate them.

What you want is the ability for an application to tell its current preferred orientation (at runtime), which overrides shell's decision on rotating an app (among its supported orientations) based on the device physical position etc.

So this is a different topic and it's being tracked on https://bugs.launchpad.net/mir/+bug/1382209

[Daniel d'Andrada (dandrader)]

Mir added support for it but qtubuntu (for qt based apps), qtmir and unity8 are not using it yet.