Layout Questions and Feedback

[zicklag]

Hey there, I just tried EGUI for the first time today and got my baisc GUI project up and going really quickly. It's pretty great. 😃

So far the widgets seem pretty effective and you've got a lot of good features, but the one area I felt was a little lacking was the layout. I don't say this to critisize or anything, so don't take this the wrong way. Layout just felt a little cumbersome and like it wasn't easily possible to make responsive UI's that handle different screen sizes well.

I haven't gotten deep into it yet, and I think there are ways to make it do stuff I haven't found yet, but things like easily adding paddings or margins to frames with options for resizing or wrapping colums would be nice. And maybe all that I need is some basic examples to show how to do certain things. This is all my less-than-24-hours quick evaluation as I throw together a project so again, I'm not doing a heavy criticism of it. 🙂

That's just my first impression. I am really enjoying using this so far, and I think you've done well to deliver "The easiest to use GUI libary" ( not that I've tried many yet, but you're doing great! )

---

Also I notice you had this as a non-goal in the README:

Advanced and flexible layouts (that's fundamentally incompatible with immediate mode)

I just wanted to ask to get a better understanding of this myself, but something like using stretch for flexbox layout would be impossible, then correct? Is it because advanced layout systems takes too much time to run every frame? I was curious, even if it were a non-goal for EGUI if it would be possible to create an integration with stretch in another crate so I wanted to get a little more elaboration on "fundamentally incompatible" if you can spare the time, for my own education. 😉

[zicklag]

Ah, I did find out a nicer way to do Frame's with margins than I had found earlier:

Frame {
    margin: Vec2::new(6.0, 6.0),
    ..Default::default()
}
.show(ui, |ui| {
    // Put stuff in it
});

That's nicer than what I did earlier:

let mut frame = Frame::default();
frame.margin = Vec2::new(6.0, 6.0);
frame.show(ui, |ui| {
    // put stuff in it
});

But I'm thinking maybe we should still have a margin convenience function for doing that.

I think I'll just use this thread to document my findings as I experiment. ;)

[emilk]

Suggestions welcome, as are user stories (i.e. "this is why I want to do this").

I think I'll just use this thread to document my findings as I experiment.

Sounds good!

[emilk]

Hi! Thanks for trying egui, and glad you like it :)

Yes, egui is still lacking when it comes to layouts. For instance, grid layouts was only added last month. Even when things are possible they are not well documented, and a big reason for this is because egui is still evolving quickly, and any docs will become outdated fast. The best chance is finding something similar to what you want in the demo and try to copy that (see for instance the "Layout Test" window).

I wanted to get a little more elaboration on "fundamentally incompatible" if you can spare the time, for my own education.

Great question! In fact, I decided to spend some time to explain this in detail in the project README.md: https://github.com/emilk/egui#why-immediate-mode. As you can see, the fundamental problem is that most advanced layouts requires knowing the sizes of things before they can be positioned, but egui needs to know the positions of things before it can do the layout. You can still do nice layouts for fixed-sized widgets. For instance, if you have a bunch of images of known sizes you can probably use stretch to layout them and then just explicitly place them inside an egui Ui (https://docs.rs/egui/0.9.0/egui/struct.Ui.html#method.put)

[zicklag]

Awesome, that helps a lot, thanks! Good explanation in the readme.

I've had some fun with egui in the last few days and gotten a simple app working. I think my favorite part about it so far is the fact that it works so seamlessly on desktop and web. Your getting started template repo was also a huge timesaver. It let me write my custom calculator-type app in Rust and run it in the browser with no problems.

Anyway, I'll be keeping an eye on egui. Thanks for the lib!

[emilk]

That's great to hear, thanks for writing that! 😄