Text2d bounding box fix (#20148)

# Objective

`calculate_bounds_text2d` generates `Aabb`s with the wrong size and
position for `Text2d` entities with `TextBounds`, which breaks culling.

## Solution

Calculate the correct bounds.

Fixes #20145

## Testing

```
cargo run --example testbed_2d
```

#### main
<img width="661" height="469" alt="text2daabb"
src="https://github.com/user-attachments/assets/c10b64ed-6e0d-4c4e-a81d-6ae2248d752a"
/>

#### This PR

<img width="441" height="308" alt="fixed-text2d-aabbs"
src="https://github.com/user-attachments/assets/bc715bf0-b77f-4149-9c6d-a5a8c1982780"
/>

crates/bevy_text/src/text2d.rs

@@ -17,7 +17,7 @@ use bevy_ecs::{
     system::{Commands, Local, Query, Res, ResMut},
 };
 use bevy_image::prelude::*;
-use bevy_math::Vec2;
+use bevy_math::{Vec2, Vec3};
 use bevy_reflect::{prelude::ReflectDefault, Reflect};
 use bevy_render::sync_world::TemporaryRenderEntity;
 use bevy_render::view::{self, Visibility, VisibilityClass};
@@ -186,6 +186,7 @@ pub fn extract_text2d_sprite(
         let top_left = (Anchor::TOP_LEFT.0 - anchor.as_vec()) * size;
         let transform =
             *global_transform * GlobalTransform::from_translation(top_left.extend(0.)) * scaling;
+
         let mut color = LinearRgba::WHITE;
         let mut current_span = usize::MAX;
 
@@ -366,22 +367,17 @@ pub fn calculate_bounds_text2d(
             text_bounds.width.unwrap_or(layout_info.size.x),
             text_bounds.height.unwrap_or(layout_info.size.y),
         );
-        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();
+        let x1 = (Anchor::TOP_LEFT.0.x - anchor.as_vec().x) * size.x;
+        let x2 = (Anchor::TOP_LEFT.0.x - anchor.as_vec().x + 1.) * size.x;
+        let y1 = (Anchor::TOP_LEFT.0.y - anchor.as_vec().y - 1.) * size.y;
+        let y2 = (Anchor::TOP_LEFT.0.y - anchor.as_vec().y) * size.y;
+        let new_aabb = Aabb::from_min_max(Vec3::new(x1, y1, 0.), Vec3::new(x2, y2, 0.));
 
         if let Some(mut aabb) = aabb {
-            *aabb = Aabb {
-                center,
-                half_extents,
-            };
+            *aabb = new_aabb;
         } else {
-            commands.entity(entity).try_insert(Aabb {
-                center,
-                half_extents,
-            });
+            commands.entity(entity).try_insert(new_aabb);
         }
     }
 }

examples/testbed/2d.rs

@@ -165,7 +165,7 @@ mod text {
                 &mut commands,
                 300. * Vec3::X + y * Vec3::Y,
                 justify,
-                Some(TextBounds::new(150., 55.)),
+                Some(TextBounds::new(150., 60.)),
             );
         }
 
@@ -221,6 +221,9 @@ mod text {
                 Transform::from_translation(dest + Vec3::Z),
                 anchor,
                 DespawnOnExitState(super::Scene::Text),
+                ShowAabbGizmo {
+                    color: Some(palettes::tailwind::AMBER_400.into()),
+                },
                 children![
                     (
                         TextSpan::new(format!("{}, {}\n", anchor.x, anchor.y)),