Can support ImGuiConfigFlags_ViewportsEnable?

[Wuqiqi123]

I test it in qt5 and it works perfect.
Can you support Viewports and docking, I really like this two features.
Thanks.

[dpaulat]

Excellent - great to hear it works with Qt 5!

The backend is designed to work with Qt graphics contexts defined external to ImGui. With multi-viewports, ImGui manages the viewports and graphics contexts. I played around with it briefly, but I wasn't able to find a good way to separate that functionality and make them externally managed. The solution I had was to create an ImGui context for each widget, and that seemed to work well for my purposes. That said, I'm open to alternate solutions.

I think docking might be a little bit easier to achieve. First, instead of creating an ImGui context per widget, you'd have to return to sharing a single ImGui context (this should work decently, I've tested this part). In addition, you'll need to enable docking via the enable flag using the docking branch. Per the Docking documentation, that should get you 90% of the features. While it's a starting point, I'm skeptical, as I haven't tested it with this backend. I do have some code that checks whether input occurred on a given widget, and I suspect this might need some tweaking.

I'm not sure what an entire-screen docking approach would look like, I would imagine there's a way to create an invisible Qt OpenGL widget over the entire screen as your main viewport.

There has been at least some discussion around a similar use case:
ocornut/imgui#4298

[Wuqiqi123]

Yes! I checkout imgui to docking branch and test DemoWindow. It looks works.