Text 2d alignment fix (#17365)

# Objective

`Text2d` ignores `TextBounds` when calculating the offset for text
aligment.
On main a text entity positioned in the center of the window with center
justification and 600px horizontal text bounds isn't centered like it
should be but shifted off to the right:
<img width="305" alt="hellox"
src="https://github.com/user-attachments/assets/8896c6f0-1b9f-4633-9c12-1de6eff5f3e1"
/>
(second example in the testing section below)

Fixes #14266

I already had a PR in review for this (#14270) but it used post layout
adjustment (which we want to avoid) and ignored `TextBounds`.

## Solution

* If `TextBounds` are present for an axis, use them instead of the size
of the computed text layout size to calculate the offset.
* Adjust the vertical offset of text so it's top is aligned with the top
of the texts bounding rect (when present).

## Testing

```
use bevy::prelude::*;
use bevy::color::palettes;
use bevy::sprite::Anchor;
use bevy::text::TextBounds;

fn main() {
    App::new()
        .add_plugins(DefaultPlugins)
        .add_systems(Startup, setup)
        .run();
}

fn example(commands: &mut Commands, dest: Vec3, justify: JustifyText) {
    commands.spawn((
        Sprite {
            color: palettes::css::YELLOW.into(),
            custom_size: Some(10. * Vec2::ONE),
            anchor: Anchor::Center,
            ..Default::default()
        },
        Transform::from_translation(dest),
    ));

    for a in [
        Anchor::TopLeft,
        Anchor::TopRight,
        Anchor::BottomRight,
        Anchor::BottomLeft,
    ] {
        commands.spawn((
            Text2d(format!("L R\n{:?}\n{:?}", a, justify)),
            TextFont {
                font_size: 14.0,
                ..default()
            },
            TextLayout {
                justify,
                ..Default::default()
            },
            TextBounds::new(300., 75.),
            Transform::from_translation(dest + Vec3::Z),
            a,
        ));
    }
}

fn setup(mut commands: Commands) {
    commands.spawn(Camera2d::default());

    for (i, j) in [
        JustifyText::Left,
        JustifyText::Right,
        JustifyText::Center,
        JustifyText::Justified,
    ]
    .into_iter()
    .enumerate()
    {
        example(&mut commands, (300. - 150. * i as f32) * Vec3::Y, j);
    }

    commands.spawn(Sprite {
        color: palettes::css::YELLOW.into(),
        custom_size: Some(10. * Vec2::ONE),
        anchor: Anchor::Center,
        ..Default::default()
    });
}
```

<img width="566" alt="cap"
src="https://github.com/user-attachments/assets/e6a98fa5-80b2-4380-a9b7-155bb49635b8"
/>

This probably looks really confusing but it should make sense if you
imagine each block of text surrounded by a 300x75 rectangle that is
anchored to the center of the yellow square.

# 

```
use bevy::prelude::*;
use bevy::sprite::Anchor;
use bevy::text::TextBounds;

fn main() {
    App::new()
        .add_plugins(DefaultPlugins)
        .add_systems(Startup, setup)
        .run();
}

fn setup(mut commands: Commands) {
    commands.spawn(Camera2d::default());

    commands.spawn((
        Text2d::new("hello"),
        TextFont {
            font_size: 60.0,
            ..default()
        },
        TextLayout::new_with_justify(JustifyText::Center),
        TextBounds::new(600., 200.),
        Anchor::Center,
    ));
}
```

<img width="338" alt="hello"
src="https://github.com/user-attachments/assets/e5e89364-afda-4baa-aca8-df4cdacbb4ed"
/>

The text being above the center is intended. When `TextBounds` are
present, the text block's offset is calculated using its `TextBounds`
not the layout size returned by cosmic-text.

# 

Probably we should add a vertical alignment setting for Text2d. Didn't
do it here as this is intended for a 0.15.2 release.

crates/bevy_text/src/text2d.rs

@@ -138,6 +138,7 @@ pub fn extract_text2d_sprite(
             &ViewVisibility,
             &ComputedTextBlock,
             &TextLayoutInfo,
+            &TextBounds,
             &Anchor,
             &GlobalTransform,
         )>,
@@ -156,6 +157,7 @@ pub fn extract_text2d_sprite(
         view_visibility,
         computed_block,
         text_layout_info,
+        text_bounds,
         anchor,
         global_transform,
     ) in text2d_query.iter()
@@ -164,11 +166,14 @@ pub fn extract_text2d_sprite(
             continue;
         }
 
-        let text_anchor = -(anchor.as_vec() + 0.5);
+        let size = Vec2::new(
-        let alignment_translation = text_layout_info.size * text_anchor;
+            text_bounds.width.unwrap_or(text_layout_info.size.x),
-        let transform = *global_transform
+            text_bounds.height.unwrap_or(text_layout_info.size.y),
-            * GlobalTransform::from_translation(alignment_translation.extend(0.))
+        );
-            * scaling;
+        let bottom_left =
+            -(anchor.as_vec() + 0.5) * size + (size.y - text_layout_info.size.y) * Vec2::Y;
+        let transform =
+            *global_transform * GlobalTransform::from_translation(bottom_left.extend(0.)) * scaling;
         let mut color = LinearRgba::WHITE;
         let mut current_span = usize::MAX;
         for PositionedGlyph {
@@ -319,16 +324,27 @@ pub fn scale_value(value: f32, factor: f32) -> f32 {
 pub fn calculate_bounds_text2d(
     mut commands: Commands,
     mut text_to_update_aabb: Query<
-        (Entity, &TextLayoutInfo, &Anchor, Option<&mut Aabb>),
+        (
+            Entity,
+            &TextLayoutInfo,
+            &Anchor,
+            &TextBounds,
+            Option<&mut Aabb>,
+        ),
         (Changed<TextLayoutInfo>, Without<NoFrustumCulling>),
     >,
 ) {
-    for (entity, layout_info, anchor, aabb) in &mut text_to_update_aabb {
+    for (entity, layout_info, anchor, text_bounds, aabb) in &mut text_to_update_aabb {
-        // `Anchor::as_vec` gives us an offset relative to the text2d bounds, by negating it and scaling
+        let size = Vec2::new(
-        // by the logical size we compensate the transform offset in local space to get the center.
+            text_bounds.width.unwrap_or(layout_info.size.x),
-        let center = (-anchor.as_vec() * layout_info.size).extend(0.0).into();
+            text_bounds.height.unwrap_or(layout_info.size.y),
-        // Distance in local space from the center to the x and y limits of the text2d bounds.
+        );
-        let half_extents = (layout_info.size / 2.0).extend(0.0).into();
+        let center = (-anchor.as_vec() * size + (size.y - layout_info.size.y) * Vec2::Y)
+            .extend(0.)
+            .into();
+
+        let half_extents = (0.5 * layout_info.size).extend(0.0).into();
+
         if let Some(mut aabb) = aabb {
             *aabb = Aabb {
                 center,

examples/2d/text2d.rs

@@ -119,30 +119,40 @@ fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
         Transform::from_translation(Vec3::new(-400.0, -250.0, 0.0)),
     ));
 
-    for (text_anchor, color) in [
+    commands
-        (Anchor::TopLeft, Color::Srgba(RED)),
+        .spawn((
-        (Anchor::TopRight, Color::Srgba(LIME)),
+            Sprite {
-        (Anchor::BottomRight, Color::Srgba(BLUE)),
+                color: Color::Srgba(LIGHT_CYAN),
-        (Anchor::BottomLeft, Color::Srgba(YELLOW)),
+                custom_size: Some(Vec2::new(10., 10.)),
-    ] {
+                ..Default::default()
-        commands
+            },
-            .spawn((
+            Transform::from_translation(250. * Vec3::Y),
-                Text2d::new(" Anchor".to_string()),
+        ))
-                slightly_smaller_text_font.clone(),
+        .with_children(|commands| {
-                Transform::from_translation(250. * Vec3::Y),
+            for (text_anchor, color) in [
-                text_anchor,
+                (Anchor::TopLeft, Color::Srgba(RED)),
-            ))
+                (Anchor::TopRight, Color::Srgba(LIME)),
-            .with_child((
+                (Anchor::BottomRight, Color::Srgba(BLUE)),
-                TextSpan("::".to_string()),
+                (Anchor::BottomLeft, Color::Srgba(YELLOW)),
-                slightly_smaller_text_font.clone(),
+            ] {
-                TextColor(LIGHT_GREY.into()),
+                commands
-            ))
+                    .spawn((
-            .with_child((
+                        Text2d::new(" Anchor".to_string()),
-                TextSpan(format!("{text_anchor:?} ")),
+                        slightly_smaller_text_font.clone(),
-                slightly_smaller_text_font.clone(),
+                        text_anchor,
-                TextColor(color),
+                    ))
-            ));
+                    .with_child((
-    }
+                        TextSpan("::".to_string()),
+                        slightly_smaller_text_font.clone(),
+                        TextColor(LIGHT_GREY.into()),
+                    ))
+                    .with_child((
+                        TextSpan(format!("{text_anchor:?} ")),
+                        slightly_smaller_text_font.clone(),
+                        TextColor(color),
+                    ));
+            }
+        });
 }
 
 fn animate_translation(