fix(gizmos): scale child positions on viewport resize + add messages

bevy_editor_panes/bevy_3d_viewport/src/lib.rs

@@ -17,11 +17,10 @@ use bevy_editor_cam::prelude::{DefaultEditorCamPlugins, EditorCam};
 use bevy_editor_styles::Theme;
 use bevy_infinite_grid::{InfiniteGrid, InfiniteGridPlugin, InfiniteGridSettings};
 use bevy_pane_layout::prelude::*;
-use bevy_transform_gizmos::{TransformGizmo, prelude::*};
+use bevy_transform_gizmos::{TransformGizmo, messages::ViewportResized, prelude::*};
 use view_gizmo::ViewGizmoPlugin;
 
 use crate::{selection_box::SelectionBoxPlugin, view_gizmo::view_gizmo_node};
-
 mod selection_box;
 mod view_gizmo;
 
@@ -50,6 +49,7 @@ impl Plugin for Viewport3dPanePlugin {
         }
 
         app.add_plugins((DefaultEditorCamPlugins, ViewGizmoPlugin, SelectionBoxPlugin))
+            .add_message::<ViewportResized>()
             .add_systems(Startup, setup)
             .add_systems(
                 First,
@@ -231,6 +231,7 @@ fn update_render_target_size(
     bodies: Query<&PaneContentNode>,
     children_query: Query<&Children>,
     computed_node_query: Query<&ComputedNode, Changed<ComputedNode>>,
+    mut messages: MessageWriter<ViewportResized>,
     mut images: ResMut<Assets<Image>>,
 ) {
     for (pane_root, viewport) in &query {
@@ -246,7 +247,11 @@ fn update_render_target_size(
         };
         // TODO Convert to physical pixels
         let content_node_size = computed_node.size();
-
+        let size_array = [content_node_size.x, content_node_size.y];
+        messages.write(ViewportResized {
+            pane_entity: pane_root,
+            size: size_array,
+        });
         let camera = camera_query.get_mut(viewport.camera_id).unwrap();
 
         let image_handle = camera.target.as_image().unwrap();

crates/bevy_events/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "bevy_events"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+bevy.workspace = true
+bevy_editor_core.workspace = true
+
+[lints]
+workspace = true

crates/bevy_events/src/lib.rs

@@ -0,0 +1,16 @@
+//! This module contains events and messages used throughout the Bevy editor
+use bevy::prelude::Entity;
+use bevy::prelude::Message;
+
+/// Viewport size in pixels as a 2D vector.
+pub type ViewportSize = [f32; 2];
+
+/// Event emitted when a viewport (pane/editor panel) resizes.
+/// Used for dynamic gizmo scaling
+#[derive(Message, Clone)]
+pub struct ViewportResized {
+    /// Entity of the pane/viewport that resized (for multi-pane editors).
+    pub pane_entity: Entity,
+    /// New viewport size in pixels.
+    pub size: ViewportSize,
+}

crates/bevy_transform_gizmos/src/lib.rs

@@ -17,9 +17,11 @@ use bevy::{prelude::*, transform::TransformSystems};
 use bevy_editor_core::selection::EditorSelection;
 use mesh::{RotationGizmo, ViewTranslateGizmo};
 
+use messages::ViewportResized;
 use normalization::*;
 
 mod mesh;
+pub mod messages;
 pub mod normalization;
 
 /// Crate prelude.
@@ -103,6 +105,8 @@ pub struct TransformGizmoSettings {
     pub snap_enabled: bool,
     /// Current gizmo mode.
     pub mode: GizmoMode,
+    /// Current gizmo scale.
+    pub viewport_scale: f32,
 }
 
 impl Default for TransformGizmoSettings {
@@ -115,6 +119,7 @@ impl Default for TransformGizmoSettings {
             angle_snap: 15.0,   // 15 degree angle snapping
             scale_snap: 0.1,    // 0.1 scale increment snapping
             snap_enabled: true, // Enable snapping by default
+            viewport_scale: 1.0,
             mode: GizmoMode::default(),
         }
     }
@@ -129,6 +134,8 @@ impl Plugin for TransformGizmoPlugin {
         if !app.is_plugin_added::<MeshPickingPlugin>() {
             app.add_plugins(MeshPickingPlugin);
         }
+        app.add_message::<ViewportResized>();
+
         app.init_resource::<TransformGizmoSettings>()
             .add_plugins(Ui3dNormalizationPlugin)
             .add_message::<TransformGizmoEvent>()
@@ -164,6 +171,7 @@ impl Plugin for TransformGizmoPlugin {
                 (adjust_view_translate_gizmo, gizmo_cam_copy_settings)
                     .chain()
                     .in_set(TransformGizmoSystems::Drag),
+                transform_gizmo_viewport_handler,
             )
                 .chain()
                 .in_set(TransformGizmoSystems::Main)
@@ -661,6 +669,7 @@ fn place_gizmo(
 
 fn propagate_gizmo_elements(
     gizmo: Query<(&GlobalTransform, &Children), With<TransformGizmo>>,
+    settings: Res<TransformGizmoSettings>,
     mut gizmo_parts_query: Query<(&Transform, &mut GlobalTransform), Without<TransformGizmo>>,
 ) {
     if let Ok((gizmo_pos, gizmo_parts)) = gizmo.single() {
@@ -669,7 +678,12 @@ fn propagate_gizmo_elements(
                 error!("Malformed transform gizmo");
                 continue;
             };
-            *g_transform = gizmo_pos.mul_transform(*transform);
+            let scaled_transform = Transform {
+                translation: transform.translation * settings.viewport_scale,
+                rotation: transform.rotation,
+                scale: Vec3::splat(settings.viewport_scale),
+            };
+            *g_transform = gizmo_pos.mul_transform(scaled_transform);
         }
     }
 }
@@ -866,3 +880,14 @@ fn update_gizmo_visibility(
         }
     }
 }
+
+fn transform_gizmo_viewport_handler(
+    mut messages: MessageReader<ViewportResized>,
+    mut settings: ResMut<TransformGizmoSettings>,
+) {
+    for msg in messages.read() {
+        let viewport_height = msg.size[1];
+        let scale = (viewport_height / 600.0).clamp(0.3, 3.0);
+        settings.viewport_scale = scale;
+    }
+}

crates/bevy_transform_gizmos/src/messages.rs

@@ -0,0 +1,16 @@
+//! This module contains events/messages used to communicate with the transform gizmo plugin.
+use bevy::prelude::Entity;
+use bevy::prelude::Message;
+
+/// Viewport size in pixels as a 2D vector.
+pub type ViewportSize = [f32; 2];
+
+/// Event emitted when a viewport (pane/editor panel) resizes.
+/// Used for dynamic gizmo scaling
+#[derive(Message, Clone)]
+pub struct ViewportResized {
+    /// Entity of the pane/viewport that resized (for multi-pane editors).
+    pub pane_entity: Entity,
+    /// New viewport size in pixels.
+    pub size: ViewportSize,
+}