Questions about ways to disable window scrolling

[achabense]

Version/Branch of Dear ImGui:

Version 1.92.2b

Back-ends:

Any (imgui_impl_sdl3.cpp + imgui_impl_sdlrenderer3.cpp)

Compiler, OS:

Any (MSVC + Win10)

Full config/build information:

No response

Details:

I have two related questions about ways to disable window-scrolling:

1. About ctrl to disable scrolling:
   Currently, pressing ctrl will disable window scrolling. This is intentionally handled in the codebase, and I want to rely on this behavior (to assume the window won't be scrolled when using ctrl+wheel to set some custom values).
   

   imgui/imgui.cpp

   Lines 10295 to 10296 in 960921f

   	if (g.IO.KeyCtrl)
   	return;

   
   However, in the same function there is a comment about obsoleteness, and I cannot make sure - does it only apply to FontAllowUserScaling, or does it also apply to the ctrl-to-disable-scrolling behavior?
   

   imgui/imgui.cpp

   Lines 10276 to 10278 in 960921f

   	// Zoom / Scale window
   	// FIXME-OBSOLETE: This is an old feature, it still works but pretty much nobody is using it and may be best redesigned.
   	if (wheel.y != 0.0f && g.IO.KeyCtrl && g.IO.FontAllowUserScaling)

2. About custom way to disable scrolling:
   I want to further disable window scrolling under some custom conditions (e.g. when certain buttons are pressed / certain popups displayed). Currently I'm using ImGui::SetKeyOwner(ImGuiKey_MouseWheelY, ImGuiKeyOwner_Any, ImGuiInputFlags_LockThisFrame), which seems to work. However (for easier maintenance) what's the recommended way to do this?

Screenshots/Video:

No response

Minimal, Complete and Verifiable Example code:

No response

[ocornut]

assume the window won't be scrolled when using ctrl+wheel to set some custom values

This likely isn't going to change.

However, in the same function there is a comment about obsoleteness, and I cannot make sure - does it only apply to FontAllowUserScaling, or does it also apply to the ctrl-to-disable-scrolling behavior?

The comment is about FontAllowUserScaling. However I have been meaning to reevaluate this comment: since 1.92, that feature which used to be not really usable has become actually functional and potentially interesting again. I haven't yet got around to evaluate how it would work since i'm not done with general scaling, which is why it hasn't been advertised much. I should update this comment.

Currently I'm using ImGui::SetKeyOwner(ImGuiKey_MouseWheelY, ImGuiKeyOwner_Any, ImGuiInputFlags_LockThisFrame), which seems to work. However (for easier maintenance) what's the recommended way to do this?

Either this either ImGui::SetKeyOwner(ImGuiKey_MouseWheelY, your_id); would work equally.
They are both correct assuming you want to hook the whole key (as opposed to the shortcut, the key would be owned regardless of which mods are held).

None that there's also a ImGuiWindowFlags_NoScrollWithMouse flag which does that for both axis.
If it was designed today this probably wouldn't be a window flag but instead a function that would essentially call the SetKeyOwner() blurb you used above.

[achabense]

Thanks a lot for the info!

[ocornut]

Closing as answered, but let me know if something is missing or you need anything!