bevy/examples/ui/font_atlas_debug.rs
ira 9f906fdc8b Improve ergonomics and reduce boilerplate around creating text elements. (#5343)
# Objective

Creating UI elements is very boilerplate-y with lots of indentation.
This PR aims to reduce boilerplate around creating text elements.

## Changelog

* Renamed `Text::with_section` to `from_section`.
  It no longer takes a `TextAlignment` as argument, as the vast majority of cases left it `Default::default()`.
* Added `Text::from_sections` which creates a `Text` from a list of `TextSections`.
  Reduces line-count and reduces indentation by one level.
* Added `Text::with_alignment`.
  A builder style method for setting the `TextAlignment` of a `Text`.
* Added `TextSection::new`.
  Does not reduce line count, but reduces character count and made it easier to read. No more `.to_string()` calls!
* Added `TextSection::from_style` which creates an empty `TextSection` with a style.
  No more empty strings! Reduces indentation.
* Added `TextAlignment::CENTER` and friends.
* Added methods to `TextBundle`. `from_section`, `from_sections`, `with_text_alignment` and `with_style`.

## Note for reviewers.
Because of the nature of these changes I recommend setting diff view to 'split'.
~~Look for the book icon~~ cog in the top-left of the Files changed tab.

Have fun reviewing ❤️
<sup> >:D </sup>

## Migration Guide

`Text::with_section` was renamed to `from_section` and no longer takes a `TextAlignment` as argument.
Use `with_alignment` to set the alignment instead.

Co-authored-by: devil-ira <justthecooldude@gmail.com>
2022-07-20 14:14:29 +00:00

92 lines
2.7 KiB
Rust

//! This example illustrates how `FontAtlas`'s are populated.
//! Bevy uses `FontAtlas`'s under the hood to optimize text rendering.
use bevy::{prelude::*, text::FontAtlasSet};
fn main() {
App::new()
.init_resource::<State>()
.insert_resource(ClearColor(Color::BLACK))
.add_plugins(DefaultPlugins)
.add_startup_system(setup)
.add_system(text_update_system)
.add_system(atlas_render_system)
.run();
}
struct State {
atlas_count: u32,
handle: Handle<Font>,
timer: Timer,
}
impl Default for State {
fn default() -> Self {
Self {
atlas_count: 0,
handle: Handle::default(),
timer: Timer::from_seconds(0.05, true),
}
}
}
fn atlas_render_system(
mut commands: Commands,
mut state: ResMut<State>,
font_atlas_sets: Res<Assets<FontAtlasSet>>,
texture_atlases: Res<Assets<TextureAtlas>>,
) {
if let Some(set) = font_atlas_sets.get(&state.handle.as_weak::<FontAtlasSet>()) {
if let Some((_size, font_atlas)) = set.iter().next() {
let x_offset = state.atlas_count as f32;
if state.atlas_count == font_atlas.len() as u32 {
return;
}
let texture_atlas = texture_atlases
.get(&font_atlas[state.atlas_count as usize].texture_atlas)
.unwrap();
state.atlas_count += 1;
commands.spawn_bundle(ImageBundle {
image: texture_atlas.texture.clone().into(),
style: Style {
position_type: PositionType::Absolute,
position: UiRect {
top: Val::Px(0.0),
left: Val::Px(512.0 * x_offset),
..default()
},
..default()
},
..default()
});
}
}
}
fn text_update_system(mut state: ResMut<State>, time: Res<Time>, mut query: Query<&mut Text>) {
if state.timer.tick(time.delta()).finished() {
for mut text in &mut query {
let c = rand::random::<u8>() as char;
let string = &mut text.sections[0].value;
if !string.contains(c) {
string.push(c);
}
}
state.timer.reset();
}
}
fn setup(mut commands: Commands, asset_server: Res<AssetServer>, mut state: ResMut<State>) {
let font_handle = asset_server.load("fonts/FiraSans-Bold.ttf");
state.handle = font_handle.clone();
commands.spawn_bundle(Camera2dBundle::default());
commands.spawn_bundle(TextBundle::from_section(
"a",
TextStyle {
font: font_handle,
font_size: 60.0,
color: Color::YELLOW,
},
));
}