bevy_mod_stylebuilder

This crate provides a set of low-level utilities for configuring bevy_ui styles using a fluent API. A StyleBuilder is an object that understands how to insert, remove, and modify Bevy style components such as Style, BackgroundColor and so on, as well as the Pickable component used by bevy_mod_picking.

StyleBuilder is extensible by implementing additional traits. In fact, all of the fluent methods are trait methods.

use bevy_mod_stylebuilder::prelude::*;

fn style_button(ss: &mut StyleBuilder) {
    ss.border(1)
        .display(ui::Display::Flex)
        .flex_direction(ui::FlexDirection::Row)
        .justify_content(ui::JustifyContent::Center)
        .align_items(ui::AlignItems::Center)
        .align_content(ui::AlignContent::Center)
        .padding((12, 0))
        .border(0)
        .color(colors::FOREGROUND)
        .cursor(CursorIcon::Pointer);
}

In most cases, you won't need to instantiate a StyleBuilder object yourself, the UI framework will pass one to you as a callback parameter. For framework authors, however, here are the steps needed to create a new StyleBuilder:

/// Construct a new StyleBuilder instance with the entity and `Styles` component.
let mut sb = StyleBuilder::new(&mut target, style);
/// Apply one or more style functions.
self.styles.apply(&mut sb);
/// Call `.finish()` to write out the changes.
sb.finish();

Most style components such as BackgroundColor are modified immediately, however Style is treated as a special case because it has so many properties: it's cached in the StyleBuilder instance and then flushed out at the end via finish().