Windows/Linux: work towards replacing native window frame with our own custom buttons

[emilk]

Work towards #1063

This PR adds the code for the new custom window frame but with the feature disabled. It should therefore be safe to merge.

The rounding of the corners is done manually for each panel. A more robust solution would be to render to an offscreen buffer and then do the rounding afterwards, but hacking that into eframe is more work than we have before release 😬

TODO

• eframe: window transparency doesn't work with wgpu emilk/egui#2680
• Put all panels within one master CentralPanel
• Add an outer frame
• Fill in gap above the upper rounding of the time panel
• Memory panel
• Check that web still works
• Check that mac still works

Future work

• Fix window resizing UI on both Wayland and Xorg
• Fix lower right corner (paint_time_ranges_gaps). Maybe turn off rounding?
• Test on Linux X11
• Test on Linux Wayland
• Test on Windows
• Custom icons for close/maximize/minimize
• I think we need to center the panel buttons?

How main looks like on Gnome/xorg:

Current state of this PR:

With CUSTOM_WINDOW_DECORATIONS enabled:

Checklist

• I have read and agree to Contributor Guide and the Code of Conduct
• I've included a screenshot or gif (if applicable)
• I've added a line to CHANGELOG.md (if this is a big enough change to warrant it)

[jleibs]

This breaks window resizing UI on both Wayland and Xorg. Without this change you still get normal drag-to-resize behavior at the window borders / corners, but with this change the edges/corners are unresponsive and resize can only be done using context menu to resize.

[jleibs]

Also, nit: but is it intentional that the bottom right-hand corner is square while the remaining corners are rounded?
Edit: I see this is mentioned in the TODO.

Still: proof of life it's working on linux and looks great:

[teh-cmc]

Same, no issue on either Wayland nor XWayland

[emilk]

This breaks window resizing UI on both Wayland and Xorg. Without this change you still get normal drag-to-resize behavior at the window borders / corners, but with this change the edges/corners are unresponsive and resize can only be done using context menu to resize.

That's a deal breaker 😭

[emilk]

Ok, I will rework this PR to hide the changes behind future flag

[emilk]

I guess nobody tested this on Windows then?

[emilk]

Ok, the feature (CUSTOM_WINDOW_DECORATIONS) is now turned off, so this should be safe to merge.

[Wumpf]

we already have icons for all of these, we should use those instead

[emilk]

I don't think we do?

We have icons for maximizing and restoring Space Views (below), but we shouldn't reuse them for the window controls

[Wumpf]

would have taken those

[SkyfallWasTaken]

Now that this PR has been merged, would it be possible for re_ui::CUSTOM_WINDOW_DECORATIONS to be set to true? (Apologies if this is the wrong place to ask)

[emilk]

No, #1063 is not ready to be closed yet - it needs testing on Linux and Windows first, and probably some fixes in eframe and/or winit: https://github.com/emilk/egui/issues?q=is%3Aissue+is%3Aopen+custom_window_frame