Box sizing, gtk4

aganzha · November 25, 2023, 9:09am

Hello, everyone.
I am trying to understand how box sizing works.
The Window set to default size 640x480. Window has a single child - Box with vertical orientation. There is a FlowBox inside vertical Box.
When app starts there are no children in FlowBox, so Its height is zero and wrapping Box and Window are 640x480.
Then some widgets are added dynamically to the FlowBox. Untill it expands to the second row, surrounding Box and Window size are 640x480, but then second row of FlowBox appears Window and Box height jumps about the height of FlowBox row. Though, there are a lot of space in them to accomodate that row and even some more rows.
Why so? Is it possible to controll that behaviour?
There are no any size settings in those widgets, except the default size of window.

lb90 · November 25, 2023, 11:01am

Sounds like a bug to me. Could you share a minimal reproducible example?

aganzha · November 25, 2023, 12:16pm

Sure. Here is minimal example in rust (should be same in other languages) + screencast demonstrating how it behaves

gist.github.com

https://gist.github.com/aganzha/d396f0d0d982f1d18839046dee3ef693

main.rs

use gtk::prelude::*;
use gtk::{glib, Application, ApplicationWindow, HeaderBar, Box, Orientation, Button, FlowBox, Label};

const APP_ID: &str = "BoxSizing";

fn main() -> glib::ExitCode {

    let app = Application::builder().application_id(APP_ID).build();
    app.connect_activate(build_ui);
    app.run()

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lb90 · November 25, 2023, 1:33pm

Hi, that’s GtkFlowBox: the orthogonal orientation always requests the most size it could possibly need (#897) · Issues · GNOME / gtk · GitLab. As explained there, to get the desired behavior you should wrap the GtkFlowBox in a GtkScrolledWindow. Let me know if anything’s missing!

aganzha · November 25, 2023, 9:30pm

Hey. It worked, thank you!

system · December 25, 2023, 9:31pm

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