# Objective Bevy sprite image mode lacks proportional scaling for the underlying texture. In many cases, it's required. For example, if it is desired to support a wide variety of screens with a single texture, it's okay to cut off some portion of the original texture. ## Solution I added scaling of the texture during the preparation step. To fill the sprite with the original texture, I scaled UV coordinates accordingly to the sprite size aspect ratio and texture size aspect ratio. To fit texture in a sprite the original `quad` is scaled and then the additional translation is applied to place the scaled quad properly. ## Testing For testing purposes could be used `2d/sprite_scale.rs`. Also, I am thinking that it would be nice to have some tests for a `crates/bevy_sprite/src/render/mod.rs:sprite_scale`. --- ## Showcase <img width="1392" alt="image" src="https://github.com/user-attachments/assets/c2c37b96-2493-4717-825f-7810d921b4bc" />
		
			
				
	
	
		
			333 lines
		
	
	
		
			12 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
			
		
		
	
	
			333 lines
		
	
	
		
			12 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
//! Shows how to use sprite scaling to fill and fit textures into the sprite.
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use bevy::prelude::*;
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fn main() {
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    App::new()
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        .add_plugins(DefaultPlugins)
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        .add_systems(
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            Startup,
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            (setup_sprites, setup_texture_atlas).after(setup_camera),
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        )
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        .add_systems(Update, animate_sprite)
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        .run();
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}
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fn setup_camera(mut commands: Commands) {
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    commands.spawn(Camera2d);
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}
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fn setup_sprites(mut commands: Commands, asset_server: Res<AssetServer>) {
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    let square = asset_server.load("textures/slice_square_2.png");
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    let banner = asset_server.load("branding/banner.png");
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    let rects = [
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        Rect {
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            size: Vec2::new(100., 225.),
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            text: "Stretched".to_string(),
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            transform: Transform::from_translation(Vec3::new(-570., 230., 0.)),
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            texture: square.clone(),
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            image_mode: SpriteImageMode::Auto,
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        },
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        Rect {
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            size: Vec2::new(100., 225.),
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            text: "Fill Center".to_string(),
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            transform: Transform::from_translation(Vec3::new(-450., 230., 0.)),
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            texture: square.clone(),
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            image_mode: SpriteImageMode::Scale(ScalingMode::FillCenter),
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        },
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        Rect {
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            size: Vec2::new(100., 225.),
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            text: "Fill Start".to_string(),
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            transform: Transform::from_translation(Vec3::new(-330., 230., 0.)),
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            texture: square.clone(),
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            image_mode: SpriteImageMode::Scale(ScalingMode::FillStart),
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        },
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        Rect {
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            size: Vec2::new(100., 225.),
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            text: "Fill End".to_string(),
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            transform: Transform::from_translation(Vec3::new(-210., 230., 0.)),
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            texture: square.clone(),
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            image_mode: SpriteImageMode::Scale(ScalingMode::FillEnd),
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        },
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        Rect {
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            size: Vec2::new(300., 100.),
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            text: "Fill Start Horizontal".to_string(),
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            transform: Transform::from_translation(Vec3::new(10., 290., 0.)),
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            texture: square.clone(),
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            image_mode: SpriteImageMode::Scale(ScalingMode::FillStart),
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        },
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        Rect {
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            size: Vec2::new(300., 100.),
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            text: "Fill End Horizontal".to_string(),
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            transform: Transform::from_translation(Vec3::new(10., 155., 0.)),
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            texture: square.clone(),
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            image_mode: SpriteImageMode::Scale(ScalingMode::FillEnd),
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        },
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        Rect {
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            size: Vec2::new(200., 200.),
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            text: "Fill Center".to_string(),
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            transform: Transform::from_translation(Vec3::new(280., 230., 0.)),
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            texture: banner.clone(),
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            image_mode: SpriteImageMode::Scale(ScalingMode::FillCenter),
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        },
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        Rect {
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            size: Vec2::new(200., 100.),
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            text: "Fill Center".to_string(),
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            transform: Transform::from_translation(Vec3::new(500., 230., 0.)),
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            texture: square.clone(),
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            image_mode: SpriteImageMode::Scale(ScalingMode::FillCenter),
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        },
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        Rect {
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            size: Vec2::new(100., 100.),
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            text: "Stretched".to_string(),
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            transform: Transform::from_translation(Vec3::new(-570., -40., 0.)),
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            texture: banner.clone(),
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            image_mode: SpriteImageMode::Auto,
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        },
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        Rect {
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            size: Vec2::new(200., 200.),
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            text: "Fit Center".to_string(),
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            transform: Transform::from_translation(Vec3::new(-400., -40., 0.)),
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            texture: banner.clone(),
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            image_mode: SpriteImageMode::Scale(ScalingMode::FitCenter),
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        },
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        Rect {
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            size: Vec2::new(200., 200.),
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            text: "Fit Start".to_string(),
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            transform: Transform::from_translation(Vec3::new(-180., -40., 0.)),
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            texture: banner.clone(),
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            image_mode: SpriteImageMode::Scale(ScalingMode::FitStart),
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        },
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        Rect {
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            size: Vec2::new(200., 200.),
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            text: "Fit End".to_string(),
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            transform: Transform::from_translation(Vec3::new(40., -40., 0.)),
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            texture: banner.clone(),
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            image_mode: SpriteImageMode::Scale(ScalingMode::FitEnd),
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        },
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        Rect {
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            size: Vec2::new(100., 200.),
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            text: "Fit Center".to_string(),
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            transform: Transform::from_translation(Vec3::new(210., -40., 0.)),
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            texture: banner.clone(),
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            image_mode: SpriteImageMode::Scale(ScalingMode::FitCenter),
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        },
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    ];
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    for rect in rects {
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        let mut cmd = commands.spawn((
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            Sprite {
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                image: rect.texture,
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                custom_size: Some(rect.size),
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                image_mode: rect.image_mode,
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                ..default()
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            },
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            rect.transform,
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        ));
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        cmd.with_children(|builder| {
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            builder.spawn((
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                Text2d::new(rect.text),
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                TextLayout::new_with_justify(JustifyText::Center),
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                TextFont::from_font_size(15.),
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                Transform::from_xyz(0., -0.5 * rect.size.y - 10., 0.),
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                bevy::sprite::Anchor::TopCenter,
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            ));
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        });
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    }
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}
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fn setup_texture_atlas(
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    mut commands: Commands,
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    asset_server: Res<AssetServer>,
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    mut texture_atlas_layouts: ResMut<Assets<TextureAtlasLayout>>,
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) {
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    commands.spawn(Camera2d);
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    let gabe = asset_server.load("textures/rpg/chars/gabe/gabe-idle-run.png");
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    let animation_indices_gabe = AnimationIndices { first: 0, last: 6 };
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    let gabe_atlas = TextureAtlas {
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        layout: texture_atlas_layouts.add(TextureAtlasLayout::from_grid(
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            UVec2::splat(24),
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            7,
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            1,
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            None,
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            None,
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        )),
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        index: animation_indices_gabe.first,
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    };
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    let sprite_sheets = [
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        SpriteSheet {
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            size: Vec2::new(120., 50.),
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            text: "Stretched".to_string(),
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            transform: Transform::from_translation(Vec3::new(-570., -200., 0.)),
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            texture: gabe.clone(),
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            image_mode: SpriteImageMode::Auto,
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            atlas: gabe_atlas.clone(),
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            indices: animation_indices_gabe.clone(),
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            timer: AnimationTimer(Timer::from_seconds(0.1, TimerMode::Repeating)),
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        },
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        SpriteSheet {
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            size: Vec2::new(120., 50.),
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            text: "Fill Center".to_string(),
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            transform: Transform::from_translation(Vec3::new(-570., -300., 0.)),
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            texture: gabe.clone(),
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            image_mode: SpriteImageMode::Scale(ScalingMode::FillCenter),
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            atlas: gabe_atlas.clone(),
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            indices: animation_indices_gabe.clone(),
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            timer: AnimationTimer(Timer::from_seconds(0.1, TimerMode::Repeating)),
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        },
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        SpriteSheet {
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            size: Vec2::new(120., 50.),
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            text: "Fill Start".to_string(),
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            transform: Transform::from_translation(Vec3::new(-430., -200., 0.)),
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            texture: gabe.clone(),
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            image_mode: SpriteImageMode::Scale(ScalingMode::FillStart),
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            atlas: gabe_atlas.clone(),
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            indices: animation_indices_gabe.clone(),
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            timer: AnimationTimer(Timer::from_seconds(0.1, TimerMode::Repeating)),
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        },
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        SpriteSheet {
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            size: Vec2::new(120., 50.),
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            text: "Fill End".to_string(),
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            transform: Transform::from_translation(Vec3::new(-430., -300., 0.)),
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            texture: gabe.clone(),
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            image_mode: SpriteImageMode::Scale(ScalingMode::FillEnd),
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            atlas: gabe_atlas.clone(),
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            indices: animation_indices_gabe.clone(),
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            timer: AnimationTimer(Timer::from_seconds(0.1, TimerMode::Repeating)),
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        },
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        SpriteSheet {
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            size: Vec2::new(50., 120.),
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            text: "Fill Center".to_string(),
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            transform: Transform::from_translation(Vec3::new(-300., -250., 0.)),
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            texture: gabe.clone(),
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            image_mode: SpriteImageMode::Scale(ScalingMode::FillCenter),
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            atlas: gabe_atlas.clone(),
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            indices: animation_indices_gabe.clone(),
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            timer: AnimationTimer(Timer::from_seconds(0.1, TimerMode::Repeating)),
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        },
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        SpriteSheet {
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            size: Vec2::new(50., 120.),
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            text: "Fill Start".to_string(),
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            transform: Transform::from_translation(Vec3::new(-190., -250., 0.)),
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            texture: gabe.clone(),
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            image_mode: SpriteImageMode::Scale(ScalingMode::FillStart),
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            atlas: gabe_atlas.clone(),
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            indices: animation_indices_gabe.clone(),
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            timer: AnimationTimer(Timer::from_seconds(0.1, TimerMode::Repeating)),
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        },
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        SpriteSheet {
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            size: Vec2::new(50., 120.),
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            text: "Fill End".to_string(),
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            transform: Transform::from_translation(Vec3::new(-90., -250., 0.)),
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            texture: gabe.clone(),
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            image_mode: SpriteImageMode::Scale(ScalingMode::FillEnd),
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            atlas: gabe_atlas.clone(),
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            indices: animation_indices_gabe.clone(),
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            timer: AnimationTimer(Timer::from_seconds(0.1, TimerMode::Repeating)),
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        },
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        SpriteSheet {
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            size: Vec2::new(120., 50.),
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            text: "Fit Center".to_string(),
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            transform: Transform::from_translation(Vec3::new(20., -200., 0.)),
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            texture: gabe.clone(),
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            image_mode: SpriteImageMode::Scale(ScalingMode::FitCenter),
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            atlas: gabe_atlas.clone(),
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            indices: animation_indices_gabe.clone(),
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            timer: AnimationTimer(Timer::from_seconds(0.1, TimerMode::Repeating)),
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        },
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        SpriteSheet {
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            size: Vec2::new(120., 50.),
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            text: "Fit Start".to_string(),
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            transform: Transform::from_translation(Vec3::new(20., -300., 0.)),
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            texture: gabe.clone(),
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            image_mode: SpriteImageMode::Scale(ScalingMode::FitStart),
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            atlas: gabe_atlas.clone(),
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            indices: animation_indices_gabe.clone(),
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            timer: AnimationTimer(Timer::from_seconds(0.1, TimerMode::Repeating)),
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        },
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        SpriteSheet {
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            size: Vec2::new(120., 50.),
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            text: "Fit End".to_string(),
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            transform: Transform::from_translation(Vec3::new(160., -200., 0.)),
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            texture: gabe.clone(),
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            image_mode: SpriteImageMode::Scale(ScalingMode::FitEnd),
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            atlas: gabe_atlas.clone(),
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            indices: animation_indices_gabe.clone(),
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            timer: AnimationTimer(Timer::from_seconds(0.1, TimerMode::Repeating)),
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        },
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    ];
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    for sprite_sheet in sprite_sheets {
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        let mut cmd = commands.spawn((
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            Sprite {
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                image_mode: sprite_sheet.image_mode,
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                custom_size: Some(sprite_sheet.size),
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                ..Sprite::from_atlas_image(sprite_sheet.texture.clone(), sprite_sheet.atlas.clone())
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            },
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            sprite_sheet.indices,
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            sprite_sheet.timer,
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            sprite_sheet.transform,
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        ));
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        cmd.with_children(|builder| {
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            builder.spawn((
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                Text2d::new(sprite_sheet.text),
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                TextLayout::new_with_justify(JustifyText::Center),
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                TextFont::from_font_size(15.),
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                Transform::from_xyz(0., -0.5 * sprite_sheet.size.y - 10., 0.),
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                bevy::sprite::Anchor::TopCenter,
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            ));
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        });
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    }
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}
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struct Rect {
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    size: Vec2,
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    text: String,
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    transform: Transform,
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    texture: Handle<Image>,
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    image_mode: SpriteImageMode,
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}
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struct SpriteSheet {
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    size: Vec2,
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    text: String,
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    transform: Transform,
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    texture: Handle<Image>,
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    image_mode: SpriteImageMode,
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    atlas: TextureAtlas,
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    indices: AnimationIndices,
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    timer: AnimationTimer,
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}
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#[derive(Component, Clone)]
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struct AnimationIndices {
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    first: usize,
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    last: usize,
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}
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#[derive(Component, Deref, DerefMut)]
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struct AnimationTimer(Timer);
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fn animate_sprite(
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    time: Res<Time>,
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    mut query: Query<(&AnimationIndices, &mut AnimationTimer, &mut Sprite)>,
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) {
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    for (indices, mut timer, mut sprite) in &mut query {
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        timer.tick(time.delta());
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        if timer.just_finished() {
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            if let Some(atlas) = &mut sprite.texture_atlas {
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                atlas.index = if atlas.index == indices.last {
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                    indices.first
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                } else {
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                    atlas.index + 1
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                };
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            }
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        }
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    }
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}
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