bevy/examples/ui/z_index.rs
ickshonpe eaac730617 Fix the Size helper functions using the wrong default value and improve the UI examples (#7626)
# Objective
`Size::width` sets the `height` field to `Val::DEFAULT` which is `Val::Undefined`, but the default for `Size` `height` is `Val::Auto`. 
`Size::height` has the same problem, but with the `width` field. 

The UI examples specify numeric values in many places where they could either be elided or replaced by composition of the Flex enum properties.

related: https://github.com/bevyengine/bevy/pull/7468
fixes: https://github.com/bevyengine/bevy/issues/6498

## Solution
Change `Size::width` so it sets `height` to `Val::AUTO` and change `Size::height` so it sets `width` to `Val::AUTO`.
Added some tests so this doesn't happen again.

## Changelog
Changed `Size::width` so it sets the `height` to `Val::AUTO`.
Changed `Size::height` so it sets the `width` to `Val::AUTO`.
Added tests to `geometry.rs` for `Size` and `UiRect` to ensure correct behaviour.
Simplified the UI examples. Replaced numeric values with the Flex property enums or elided them where possible, and removed the remaining use of auto margins.

## Migration Guide
The `Size::width` constructor function now sets the `height` to `Val::Auto` instead of `Val::Undefined`.
The `Size::height` constructor function now sets the `width` to `Val::Auto` instead of `Val::Undefined`.
2023-02-11 23:07:16 +00:00

134 lines
5.7 KiB
Rust

//! Demonstrates how to use the z-index component on UI nodes to control their relative depth
//!
//! It uses colored boxes with different z-index values to demonstrate how it can affect the order of
//! depth of nodes compared to their siblings, but also compared to the entire UI.
use bevy::prelude::*;
fn main() {
App::new()
.insert_resource(ClearColor(Color::BLACK))
.add_plugins(DefaultPlugins)
.add_startup_system(setup)
.run();
}
fn setup(mut commands: Commands) {
commands.spawn(Camera2dBundle::default());
// spawn the container with default z-index.
// the default z-index value is `ZIndex::Local(0)`.
// because this is a root UI node, using local or global values will do the same thing.
commands
.spawn(NodeBundle {
style: Style {
size: Size::width(Val::Percent(100.0)),
align_items: AlignItems::Center,
justify_content: JustifyContent::Center,
..default()
},
..default()
})
.with_children(|parent| {
parent
.spawn(NodeBundle {
background_color: Color::GRAY.into(),
style: Style {
size: Size::new(Val::Px(180.0), Val::Px(100.0)),
..default()
},
..default()
})
.with_children(|parent| {
// spawn a node with default z-index.
parent.spawn(NodeBundle {
background_color: Color::RED.into(),
style: Style {
position_type: PositionType::Absolute,
position: UiRect {
left: Val::Px(10.0),
bottom: Val::Px(40.0),
..default()
},
size: Size::new(Val::Px(100.0), Val::Px(50.0)),
..default()
},
..default()
});
// spawn a node with a positive local z-index of 2.
// it will show above other nodes in the grey container.
parent.spawn(NodeBundle {
z_index: ZIndex::Local(2),
background_color: Color::BLUE.into(),
style: Style {
position_type: PositionType::Absolute,
position: UiRect {
left: Val::Px(45.0),
bottom: Val::Px(30.0),
..default()
},
size: Size::new(Val::Px(100.0), Val::Px(50.0)),
..default()
},
..default()
});
// spawn a node with a negative local z-index.
// it will show under other nodes in the grey container.
parent.spawn(NodeBundle {
z_index: ZIndex::Local(-1),
background_color: Color::GREEN.into(),
style: Style {
position_type: PositionType::Absolute,
position: UiRect {
left: Val::Px(70.0),
bottom: Val::Px(20.0),
..default()
},
size: Size::new(Val::Px(100.0), Val::Px(75.0)),
..default()
},
..default()
});
// spawn a node with a positive global z-index of 1.
// it will show above all other nodes, because it's the highest global z-index in this example.
// by default, boxes all share the global z-index of 0 that the grey container is added to.
parent.spawn(NodeBundle {
z_index: ZIndex::Global(1),
background_color: Color::PURPLE.into(),
style: Style {
position_type: PositionType::Absolute,
position: UiRect {
left: Val::Px(15.0),
bottom: Val::Px(10.0),
..default()
},
size: Size::new(Val::Px(100.0), Val::Px(60.0)),
..default()
},
..default()
});
// spawn a node with a negative global z-index of -1.
// this will show under all other nodes including its parent, because it's the lowest global z-index
// in this example.
parent.spawn(NodeBundle {
z_index: ZIndex::Global(-1),
background_color: Color::YELLOW.into(),
style: Style {
position_type: PositionType::Absolute,
position: UiRect {
left: Val::Px(-15.0),
bottom: Val::Px(-15.0),
..default()
},
size: Size::new(Val::Px(100.0), Val::Px(125.0)),
..default()
},
..default()
});
});
});
}