Interaction restriction

[luiswirth]

I'm currently developing my own drawing application, which uses egui.
I have a window in which I render the pen drawings of the user. This is rendered directly with wgpu (no epaint) and egui just shows an image, which is the render target.

Drawing is done using the mouse. When a mouse button is pressed down it is supposed to draw. Unfortunately currently egui moves the window when the mouse "drags" it. How can I prevent this? I don't want the window to be fixed in place, but only moveable by the borders.

This problem is probably part of a broader one: Being able to customize how the user can interact with egui.

[emilk]

There is a painting demo at https://emilk.github.io/egui/#demo with the source code at https://github.com/emilk/egui/blob/master/egui_demo_lib/src/apps/demo/painting.rs

The critical part you are missing is Sense::drag() - this tells egui that you will be catching drags, and that egui should not use them

[luiswirth]

I think this is something very valuable for egui. Since it advertises itself as a gui framework for game engines.

Think of Unity, where the scene/game view is just a window. This setup also requires the gui to be hooked up to a custom rendering pipeline and a interaction system, which forwards the events specific to this window to some kind of scene handler.

[emilk]

Rendering custom content within an egui Ui would indeed be great, and the only way to do so currently is via a texture/image.

I just pushed this: d862ff6

now you can make an egui::Image "swallow" input with image.sense(Sense::click_and_drag())

[luiswirth]

Oh great, thanks! I will try it out, when I have time.

[luiswirth]

Nice, it works for me :).

[luiswirth]

For now this question is resolved. But I think it would be nice to really forward the events and transform the positions etc to be relative to the ui element.