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A comment on Emerging Rust GUI libraries in a WASM world. Parent comment

Re:Emerging Rust GUI libraries in a WASM world by flohofwoe on Thursday April 27, 2023 @06:17AM (#35725868)
This demo produces only a handful of draw calls to the GPU, and even though those draw calls can have hundreds of thousands of triangles, that's still as efficient as it gets.

I guess that egui works similar to Dear ImGui: only (font) texture changes and clip regions (e.g. scroll areas) require a new draw call, and that's typically just a handful to a few dozen draw calls even for complex UIs.

For long lists, Dear ImGui has a special 'ListClipper' class which allows to iterate over the visible 'slots' of a list, so that the code which describes the list UI can skip clipped items early. Not sure if egui has something similar.

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Re:Emerging Rust GUI libraries in a WASM world by Freaky on Thursday April 27, 2023 @12:04PM (#35730160)
> Dear ImGui has a special 'ListClipper' class which allows to iterate over the visible 'slots' of a list, so that the code which describes the list UI can skip clipped items early. Not sure if egui has something similar.

An egui ScrollArea can request only visible rows from a callback using show_rows:

https://docs.rs/egui/latest/egui/containers/scroll_area/stru...

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