This example is running in WebGL2 and should work in most browsers. You can check the WebGPU examples here.
//! Demonstrates how CSS Grid layout can be used to lay items out in a 2D grid
use bevy::prelude::*;
fn main() {
App::new()
.add_plugins(DefaultPlugins.set(WindowPlugin {
primary_window: Some(Window {
resolution: [800., 600.].into(),
title: "Bevy CSS Grid Layout Example".to_string(),
..default()
}),
..default()
}))
.add_systems(Startup, spawn_layout)
.run();
}
fn spawn_layout(mut commands: Commands, asset_server: Res<AssetServer>) {
let font = asset_server.load("fonts/FiraSans-Bold.ttf");
commands.spawn(Camera2dBundle::default());
// Top-level grid (app frame)
commands
.spawn(NodeBundle {
style: Style {
// Use the CSS Grid algorithm for laying out this node
display: Display::Grid,
// Make node fill the entirety it's parent (in this case the window)
width: Val::Percent(100.0),
height: Val::Percent(100.0),
// Set the grid to have 2 columns with sizes [min-content, minmax(0, 1fr)]
// - The first column will size to the size of it's contents
// - The second column will take up the remaining available space
grid_template_columns: vec![GridTrack::min_content(), GridTrack::flex(1.0)],
// Set the grid to have 3 rows with sizes [auto, minmax(0, 1fr), 20px]
// - The first row will size to the size of it's contents
// - The second row take up remaining available space (after rows 1 and 3 have both been sized)
// - The third row will be exactly 20px high
grid_template_rows: vec![
GridTrack::auto(),
GridTrack::flex(1.0),
GridTrack::px(20.),
],
..default()
},
background_color: BackgroundColor(Color::WHITE),
..default()
})
.with_children(|builder| {
// Header
builder
.spawn(NodeBundle {
style: Style {
display: Display::Grid,
// Make this node span two grid columns so that it takes up the entire top tow
grid_column: GridPlacement::span(2),
padding: UiRect::all(Val::Px(6.0)),
..default()
},
..default()
})
.with_children(|builder| {
spawn_nested_text_bundle(builder, font.clone(), "Bevy CSS Grid Layout Example");
});
// Main content grid (auto placed in row 2, column 1)
builder
.spawn(NodeBundle {
style: Style {
// Make the height of the node fill its parent
height: Val::Percent(100.0),
// Make the grid have a 1:1 aspect ratio meaning it will scale as an exact square
// As the height is set explicitly, this means the width will adjust to match the height
aspect_ratio: Some(1.0),
// Use grid layout for this node
display: Display::Grid,
// Add 24px of padding around the grid
padding: UiRect::all(Val::Px(24.0)),
// Set the grid to have 4 columns all with sizes minmax(0, 1fr)
// This creates 4 exactly evenly sized columns
grid_template_columns: RepeatedGridTrack::flex(4, 1.0),
// Set the grid to have 4 rows all with sizes minmax(0, 1fr)
// This creates 4 exactly evenly sized rows
grid_template_rows: RepeatedGridTrack::flex(4, 1.0),
// Set a 12px gap/gutter between rows and columns
row_gap: Val::Px(12.0),
column_gap: Val::Px(12.0),
..default()
},
background_color: BackgroundColor(Color::DARK_GRAY),
..default()
})
.with_children(|builder| {
// Note there is no need to specify the position for each grid item. Grid items that are
// not given an explicit position will be automatically positioned into the next available
// grid cell. The order in which this is performed can be controlled using the grid_auto_flow
// style property.
item_rect(builder, Color::ORANGE);
item_rect(builder, Color::BISQUE);
item_rect(builder, Color::BLUE);
item_rect(builder, Color::CRIMSON);
item_rect(builder, Color::CYAN);
item_rect(builder, Color::ORANGE_RED);
item_rect(builder, Color::DARK_GREEN);
item_rect(builder, Color::FUCHSIA);
item_rect(builder, Color::TEAL);
item_rect(builder, Color::ALICE_BLUE);
item_rect(builder, Color::CRIMSON);
item_rect(builder, Color::ANTIQUE_WHITE);
item_rect(builder, Color::YELLOW);
item_rect(builder, Color::PINK);
item_rect(builder, Color::YELLOW_GREEN);
item_rect(builder, Color::SALMON);
});
// Right side bar (auto placed in row 2, column 2)
builder
.spawn(NodeBundle {
style: Style {
display: Display::Grid,
// Align content towards the start (top) in the vertical axis
align_items: AlignItems::Start,
// Align content towards the center in the horizontal axis
justify_items: JustifyItems::Center,
// Add 10px padding
padding: UiRect::all(Val::Px(10.)),
// Add an fr track to take up all the available space at the bottom of the column so that the text nodes
// can be top-aligned. Normally you'd use flexbox for this, but this is the CSS Grid example so we're using grid.
grid_template_rows: vec![GridTrack::auto(), GridTrack::auto(), GridTrack::fr(1.0)],
// Add a 10px gap between rows
row_gap: Val::Px(10.),
..default()
},
background_color: BackgroundColor(Color::BLACK),
..default()
})
.with_children(|builder| {
builder.spawn(TextBundle::from_section(
"Sidebar",
TextStyle {
font: font.clone(),
font_size: 24.0,
..default()
},
));
builder.spawn(TextBundle::from_section(
"A paragraph of text which ought to wrap nicely. A paragraph of text which ought to wrap nicely. A paragraph of text which ought to wrap nicely. A paragraph of text which ought to wrap nicely. A paragraph of text which ought to wrap nicely. A paragraph of text which ought to wrap nicely. A paragraph of text which ought to wrap nicely.",
TextStyle {
font: font.clone(),
font_size: 16.0,
..default()
},
));
builder.spawn(NodeBundle::default());
});
// Footer / status bar
builder.spawn(NodeBundle {
style: Style {
// Make this node span two grid column so that it takes up the entire bottom row
grid_column: GridPlacement::span(2),
..default()
},
background_color: BackgroundColor(Color::WHITE),
..default()
});
// Modal (absolutely positioned on top of content - currently hidden: to view it, change its visibility)
builder.spawn(NodeBundle {
visibility: Visibility::Hidden,
style: Style {
position_type: PositionType::Absolute,
margin: UiRect {
top: Val::Px(100.),
bottom: Val::Auto,
left: Val::Auto,
right: Val::Auto,
},
width: Val::Percent(60.),
height: Val::Px(300.),
max_width: Val::Px(600.),
..default()
},
background_color: BackgroundColor(Color::Rgba {
red: 255.0,
green: 255.0,
blue: 255.0,
alpha: 0.8,
}),
..default()
});
});
}
/// Create a coloured rectangle node. The node has size as it is assumed that it will be
/// spawned as a child of a Grid container with `AlignItems::Stretch` and `JustifyItems::Stretch`
/// which will allow it to take it's size from the size of the grid area it occupies.
fn item_rect(builder: &mut ChildBuilder, color: Color) {
builder
.spawn(NodeBundle {
style: Style {
display: Display::Grid,
padding: UiRect::all(Val::Px(3.0)),
..default()
},
background_color: BackgroundColor(Color::BLACK),
..default()
})
.with_children(|builder| {
builder.spawn(NodeBundle {
background_color: BackgroundColor(color),
..default()
});
});
}
fn spawn_nested_text_bundle(builder: &mut ChildBuilder, font: Handle<Font>, text: &str) {
builder.spawn(TextBundle::from_section(
text,
TextStyle {
font,
font_size: 24.0,
color: Color::BLACK,
},
));
}