Entities can be dragged from the blueprint tree and streams tree to an existing view in the viewport

crates/viewer/re_blueprint_tree/src/blueprint_tree.rs

@@ -10,7 +10,7 @@ use re_types::blueprint::components::Visible;
 use re_ui::{drag_and_drop::DropTarget, list_item, ContextExt as _, DesignTokens, UiExt as _};
 use re_viewer_context::{
     contents_name_style, icon_for_container_kind, CollapseScope, Contents, DataResultNodeOrPath,
-    DragAndDropPayload, SystemCommandSender,
+    DragAndDropFeedback, DragAndDropPayload, SystemCommandSender,
 };
 use re_viewer_context::{
     ContainerId, DataQueryResult, DataResultNode, HoverHighlight, Item, ViewId, ViewerContext,
@@ -101,6 +101,7 @@ impl BlueprintTree {
 
                     // handle drag and drop interaction on empty space
                     self.handle_empty_space_drag_and_drop_interaction(
+                        ctx,
                         viewport,
                         ui,
                         empty_space_response.rect,
@@ -192,6 +193,7 @@ impl BlueprintTree {
         ctx.handle_select_hover_drag_interactions(&item_response, item, true);
 
         self.handle_root_container_drag_and_drop_interaction(
+            ctx,
             viewport,
             ui,
             Contents::Container(container_id),
@@ -275,6 +277,7 @@ impl BlueprintTree {
         viewport.set_content_visibility(ctx, &content, visible);
 
         self.handle_drag_and_drop_interaction(
+            ctx,
             viewport,
             ui,
             content,
@@ -411,6 +414,7 @@ impl BlueprintTree {
 
         viewport.set_content_visibility(ctx, &content, visible);
         self.handle_drag_and_drop_interaction(
+            ctx,
             viewport,
             ui,
             content,
@@ -629,6 +633,7 @@ impl BlueprintTree {
 
     fn handle_root_container_drag_and_drop_interaction(
         &mut self,
+        ctx: &ViewerContext<'_>,
         viewport: &ViewportBlueprint,
         ui: &egui::Ui,
         contents: Contents,
@@ -672,12 +677,13 @@ impl BlueprintTree {
         );
 
         if let Some(drop_target) = drop_target {
-            self.handle_contents_drop_target(viewport, ui, dragged_contents, &drop_target);
+            self.handle_contents_drop_target(ctx, viewport, ui, dragged_contents, &drop_target);
         }
     }
 
     fn handle_drag_and_drop_interaction(
         &mut self,
+        ctx: &ViewerContext<'_>,
         viewport: &ViewportBlueprint,
         ui: &egui::Ui,
         contents: Contents,
@@ -751,12 +757,13 @@ impl BlueprintTree {
         );
 
         if let Some(drop_target) = drop_target {
-            self.handle_contents_drop_target(viewport, ui, dragged_contents, &drop_target);
+            self.handle_contents_drop_target(ctx, viewport, ui, dragged_contents, &drop_target);
         }
     }
 
     fn handle_empty_space_drag_and_drop_interaction(
         &mut self,
+        ctx: &ViewerContext<'_>,
         viewport: &ViewportBlueprint,
         ui: &egui::Ui,
         empty_space: egui::Rect,
@@ -792,12 +799,13 @@ impl BlueprintTree {
                 usize::MAX,
             );
 
-            self.handle_contents_drop_target(viewport, ui, dragged_contents, &drop_target);
+            self.handle_contents_drop_target(ctx, viewport, ui, dragged_contents, &drop_target);
         }
     }
 
     fn handle_contents_drop_target(
         &mut self,
+        ctx: &ViewerContext<'_>,
         viewport: &ViewportBlueprint,
         ui: &Ui,
         dragged_contents: &[Contents],
@@ -816,6 +824,8 @@ impl BlueprintTree {
             false
         };
         if dragged_contents.iter().any(parent_contains_dragged_content) {
+            ctx.drag_and_drop_manager
+                .set_feedback(DragAndDropFeedback::Reject);
             return;
         }
 
@@ -826,7 +836,9 @@ impl BlueprintTree {
         );
 
         let Contents::Container(target_container_id) = drop_target.target_parent_id else {
-            // this shouldn't append
+            // this shouldn't happen
+            ctx.drag_and_drop_manager
+                .set_feedback(DragAndDropFeedback::Reject);
             return;
         };
 
@@ -839,6 +851,8 @@ impl BlueprintTree {
 
             egui::DragAndDrop::clear_payload(ui.ctx());
         } else {
+            ctx.drag_and_drop_manager
+                .set_feedback(DragAndDropFeedback::Accept);
             self.next_candidate_drop_parent_container_id = Some(target_container_id);
         }
     }

crates/viewer/re_selection_panel/src/view_entity_picker.rs

@@ -6,8 +6,10 @@ use re_data_ui::item_ui;
 use re_entity_db::{EntityPath, EntityTree, InstancePath};
 use re_log_types::{EntityPathFilter, EntityPathRule};
 use re_ui::{list_item, UiExt as _};
-use re_viewer_context::{DataQueryResult, ViewClassExt as _, ViewId, ViewerContext};
-use re_viewport_blueprint::{ViewBlueprint, ViewportBlueprint};
+use re_viewer_context::{DataQueryResult, ViewId, ViewerContext};
+use re_viewport_blueprint::{
+    create_entity_add_info, CanAddToView, EntityAddInfo, ViewBlueprint, ViewportBlueprint,
+};
 
 /// Window for adding/removing entities from a view.
 ///
@@ -73,10 +75,9 @@ fn add_entities_ui(ctx: &ViewerContext<'_>, ui: &mut egui::Ui, view: &ViewBluepr
     re_tracing::profile_function!();
 
     let tree = &ctx.recording().tree();
-    // TODO(jleibs): Avoid clone
-    let query_result = ctx.lookup_query_result(view.id).clone();
+    let query_result = ctx.lookup_query_result(view.id);
     let entity_path_filter = &view.contents.entity_path_filter;
-    let entities_add_info = create_entity_add_info(ctx, tree, view, &query_result);
+    let entities_add_info = create_entity_add_info(ctx, tree, view, query_result);
 
     list_item::list_item_scope(ui, "view_entity_picker", |ui| {
         add_entities_tree_ui(
@@ -85,7 +86,7 @@ fn add_entities_ui(ctx: &ViewerContext<'_>, ui: &mut egui::Ui, view: &ViewBluepr
             &tree.path.to_string(),
             tree,
             view,
-            &query_result,
+            query_result,
             entity_path_filter,
             &entities_add_info,
         );
@@ -263,116 +264,3 @@ fn add_entities_line_ui(
         }
     });
 }
-
-/// Describes if an entity path can be added to a view.
-#[derive(Clone, PartialEq, Eq)]
-enum CanAddToView {
-    Compatible { already_added: bool },
-    No { reason: String },
-}
-
-impl Default for CanAddToView {
-    fn default() -> Self {
-        Self::Compatible {
-            already_added: false,
-        }
-    }
-}
-
-impl CanAddToView {
-    /// Can be generally added but view might already have this element.
-    pub fn is_compatible(&self) -> bool {
-        match self {
-            Self::Compatible { .. } => true,
-            Self::No { .. } => false,
-        }
-    }
-
-    /// Can be added and view doesn't have it already.
-    pub fn is_compatible_and_missing(&self) -> bool {
-        self == &Self::Compatible {
-            already_added: false,
-        }
-    }
-
-    pub fn join(&self, other: &Self) -> Self {
-        match self {
-            Self::Compatible { already_added } => {
-                let already_added = if let Self::Compatible {
-                    already_added: already_added_other,
-                } = other
-                {
-                    *already_added && *already_added_other
-                } else {
-                    *already_added
-                };
-                Self::Compatible { already_added }
-            }
-            Self::No { .. } => other.clone(),
-        }
-    }
-}
-
-#[derive(Default)]
-#[allow(dead_code)]
-struct EntityAddInfo {
-    can_add: CanAddToView,
-    can_add_self_or_descendant: CanAddToView,
-}
-
-fn create_entity_add_info(
-    ctx: &ViewerContext<'_>,
-    tree: &EntityTree,
-    view: &ViewBlueprint,
-    query_result: &DataQueryResult,
-) -> IntMap<EntityPath, EntityAddInfo> {
-    let mut meta_data: IntMap<EntityPath, EntityAddInfo> = IntMap::default();
-
-    // TODO(andreas): This should be state that is already available because it's part of the view's state.
-    let class = view.class(ctx.view_class_registry);
-    let visualizable_entities = class.determine_visualizable_entities(
-        ctx.applicable_entities_per_visualizer,
-        ctx.recording(),
-        &ctx.view_class_registry
-            .new_visualizer_collection(view.class_identifier()),
-        &view.space_origin,
-    );
-
-    tree.visit_children_recursively(|entity_path| {
-        let can_add: CanAddToView =
-            if visualizable_entities.iter().any(|(_, entities)| entities.contains(entity_path)) {
-                CanAddToView::Compatible {
-                    already_added: query_result.contains_entity(entity_path),
-                }
-            } else {
-                // TODO(#6321): This shouldn't necessarily prevent us from adding it.
-                CanAddToView::No {
-                    reason: format!(
-                        "Entity can't be displayed by any of the available visualizers in this class of view ({}).",
-                        view.class_identifier()
-                    ),
-                }
-            };
-
-        if can_add.is_compatible() {
-            // Mark parents aware that there is some descendant that is compatible
-            let mut path = entity_path.clone();
-            while let Some(parent) = path.parent() {
-                let data = meta_data.entry(parent.clone()).or_default();
-                data.can_add_self_or_descendant = data.can_add_self_or_descendant.join(&can_add);
-                path = parent;
-            }
-        }
-
-        let can_add_self_or_descendant = can_add.clone();
-        meta_data.insert(
-            entity_path.clone(),
-            EntityAddInfo {
-                can_add,
-                can_add_self_or_descendant,
-            },
-        );
-    });
-
-    meta_data
-}

crates/viewer/re_time_panel/src/lib.rs

@@ -673,6 +673,7 @@ impl TimePanel {
         } = ui
             .list_item()
             .selected(is_selected)
+            .draggable(true)
             .force_hovered(is_item_hovered)
             .show_hierarchical_with_children(
                 ui,
@@ -726,7 +727,7 @@ impl TimePanel {
             &response,
             SelectionUpdateBehavior::UseSelection,
         );
-        ctx.handle_select_hover_drag_interactions(&response, item.to_item(), false);
+        ctx.handle_select_hover_drag_interactions(&response, item.to_item(), true);
 
         let is_closed = body_response.is_none();
         let response_rect = response.rect;

crates/viewer/re_ui/src/design_tokens.rs

@@ -430,6 +430,17 @@ impl DesignTokens {
     pub fn thumbnail_background_color(&self) -> egui::Color32 {
         self.color(ColorToken::gray(S250))
     }
+
+    /// Stroke used to indicate that a UI element is a container that will receive a drag-and-drop
+    /// payload.
+    ///
+    /// Sometimes this is the UI element that is being dragged over (e.g., a view receiving a new
+    /// entity). Sometimes this is a UI element not under the pointer, but whose content is
+    /// being hovered (e.g., a container in the blueprint tree)
+    #[inline]
+    pub fn drop_target_container_stroke(&self) -> egui::Stroke {
+        egui::Stroke::new(2.0, self.color(ColorToken::blue(S350)))
+    }
 }
 
 // ----------------------------------------------------------------------------

crates/viewer/re_ui/src/list_item/list_item.rs

@@ -384,13 +384,10 @@ impl ListItem {
             let bg_rect_to_paint = ui.painter().round_rect_to_pixels(bg_rect);
 
             if drag_target {
+                let stroke = crate::design_tokens().drop_target_container_stroke();
                 ui.painter().set(
                     background_frame,
-                    Shape::rect_stroke(
-                        bg_rect_to_paint.expand(-1.0),
-                        0.0,
-                        egui::Stroke::new(1.0, ui.visuals().selection.bg_fill),
-                    ),
+                    Shape::rect_stroke(bg_rect_to_paint.shrink(stroke.width), 0.0, stroke),
                 );
             }
 

crates/viewer/re_ui/src/ui_ext.rs

@@ -1094,7 +1094,11 @@ pub trait UiExt {
                 return *span;
             }
 
-            if node.has_visible_frame() || node.is_area_ui() || node.is_root_ui() {
+            if node.has_visible_frame()
+                || node.is_area_ui()
+                || node.is_panel_ui()
+                || node.is_root_ui()
+            {
                 return (node.max_rect + node.frame().inner_margin).x_range();
             }
         }

crates/viewer/re_viewer/src/app_state.rs

@@ -8,8 +8,8 @@ use re_smart_channel::ReceiveSet;
 use re_types::blueprint::components::PanelState;
 use re_ui::{ContextExt as _, DesignTokens};
 use re_viewer_context::{
-    drag_and_drop_payload_cursor_ui, AppOptions, ApplicationSelectionState, BlueprintUndoState,
-    CommandSender, ComponentUiRegistry, PlayState, RecordingConfig, StoreContext, StoreHub,
+    AppOptions, ApplicationSelectionState, BlueprintUndoState, CommandSender, ComponentUiRegistry,
+    DragAndDropManager, PlayState, RecordingConfig, StoreContext, StoreHub,
     SystemCommandSender as _, ViewClassExt as _, ViewClassRegistry, ViewStates, ViewerContext,
 };
 use re_viewport::ViewportUi;
@@ -215,8 +215,9 @@ impl AppState {
         );
 
         // The root container cannot be dragged.
-        let undraggable_items =
-            re_viewer_context::Item::Container(viewport_ui.blueprint.root_container).into();
+        let drag_and_drop_manager = DragAndDropManager::new(re_viewer_context::Item::Container(
+            viewport_ui.blueprint.root_container,
+        ));
 
         let applicable_entities_per_visualizer =
             view_class_registry.applicable_entities_for_visualizer_systems(&recording.store_id());
@@ -278,7 +279,7 @@ impl AppState {
             render_ctx: Some(render_ctx),
             command_sender,
             focused_item,
-            undraggable_items: &undraggable_items,
+            drag_and_drop_manager: &drag_and_drop_manager,
         };
 
         // We move the time at the very start of the frame,
@@ -350,7 +351,7 @@ impl AppState {
             render_ctx: Some(render_ctx),
             command_sender,
             focused_item,
-            undraggable_items: &undraggable_items,
+            drag_and_drop_manager: &drag_and_drop_manager,
         };
 
         if *show_settings_ui {
@@ -517,7 +518,7 @@ impl AppState {
         //
 
         add_view_or_container_modal_ui(&ctx, &viewport_ui.blueprint, ui);
-        drag_and_drop_payload_cursor_ui(ctx.egui_ctx);
+        drag_and_drop_manager.payload_cursor_ui(ctx.egui_ctx);
 
         // Process deferred layout operations and apply updates back to blueprint:
         viewport_ui.save_to_blueprint_store(&ctx, view_class_registry);