Support multi-viewport on Wayland via xdg-toplevel-drag

[azonenberg]

Version/Branch of Dear ImGui:

latest docking

Back-ends:

any

Compiler, OS:

Linux

Full config/build information:

No response

Details:

Multi-viewport is currently not supported on Wayland (#8587 and others).

It appears that the new xdg-toplevel-drag protocol https://wayland.app/protocols/xdg-toplevel-drag-v1 is designed to enable exactly this sort of use case. Some new backend code would be needed to reflect the fact that we need to rely on drag/drop evens and can't use global coordinates to determine which window is being dragged where. But I disagree with previous statements that multi-viewport is impossible to implement on Wayland. This may have been true prior to the creation of xdg-toplevel-drag but if Firefox/Chrome can drag tabs into new windows and back, so can we.

Note that this will only be possible if the user is using a compositor implementing this protocol (e.g. KWin) so we will still need a check to disable multi-viewport if xdg-toplevel-drag is not available.

Screenshots/Video:

No response

Minimal, Complete and Verifiable Example code:

No response

[tokyovigilante]

Hi All,

I'm working on a native Wayland backend for imgui (my project requires features SDL doesn't support), and I'd be interested in working on this.