feat(statusbar): selection filtering by object type (FILTER pill)

Add a per-type selection filter to the scene: the FILTER pill opens a
checklist of the entity types in the layout, and unchecking a type
excludes it from interactive picking (click, box and lasso selection all
honour it). The pill lights up while any type is filtered out.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/mod.rs

@@ -177,6 +177,8 @@ pub(super) struct OpenCADStudio {
     units_popup_open: bool,
     /// True while the Isolate pill's action menu is open.
     isolate_popup_open: bool,
+    /// True while the selection-filter type picker is open.
+    selection_filter_popup_open: bool,
     /// Clean-screen mode: hide ribbon and side panels for a full canvas.
     clean_screen: bool,
     /// Quick Properties: show a compact floating property panel on selection.
@@ -756,6 +758,12 @@ pub enum Message {
     ToggleTransparencyDisplay,
     /// Toggle the Quick Properties floating panel.
     ToggleQuickProperties,
+    /// Toggle the selection-filter type picker open/closed.
+    ToggleSelectionFilterPopup,
+    /// Close the selection-filter type picker.
+    CloseSelectionFilterPopup,
+    /// Include/exclude an entity type from interactive selection.
+    ToggleSelectionFilterType(String),
     /// Toggle the drawing-units picker open/closed.
     ToggleUnitsPopup,
     /// Close the drawing-units picker.
@@ -1225,6 +1233,7 @@ impl OpenCADStudio {
             statusbar_menu_open: false,
             units_popup_open: false,
             isolate_popup_open: false,
+            selection_filter_popup_open: false,
             statusbar_config: crate::ui::statusbar_config::StatusBarConfig::load(),
             clean_screen: false,
             quick_properties: false,

src/app/update.rs

@@ -2889,6 +2889,8 @@ impl OpenCADStudio {
                                 vp_mat,
                                 bounds,
                             ));
+                            // Selection filter: keep only allowed types.
+                            handles.retain(|&h| self.tabs[i].scene.passes_selection_filter(h));
                             self.tabs[i].scene.deselect_all();
                             for h in &handles {
                                 self.tabs[i].scene.select_entity(*h, false);
@@ -2932,6 +2934,9 @@ impl OpenCADStudio {
                                     // body, not just the thin projected edges.
                                     self.tabs[i].scene.mesh_click_hit(p, vp_mat, bounds)
                                 });
+                            // Selection filter: drop a pick whose type is excluded.
+                            let hit =
+                                hit.filter(|&h| self.tabs[i].scene.passes_selection_filter(h));
                             if let Some(handle) = hit {
                                 // Individual picks accumulate (issue #47):
                                 // each plain click adds to the selection,
@@ -2980,6 +2985,8 @@ impl OpenCADStudio {
                                 vp_mat,
                                 bounds,
                             ));
+                            // Selection filter: keep only allowed types.
+                            handles.retain(|&h| self.tabs[i].scene.passes_selection_filter(h));
                             self.tabs[i].scene.deselect_all();
                             for h in &handles {
                                 self.tabs[i].scene.select_entity(*h, false);
@@ -3594,6 +3601,21 @@ impl OpenCADStudio {
                 self.quick_properties ^= true;
                 Task::none()
             }
+            Message::ToggleSelectionFilterPopup => {
+                self.selection_filter_popup_open ^= true;
+                Task::none()
+            }
+            Message::CloseSelectionFilterPopup => {
+                self.selection_filter_popup_open = false;
+                Task::none()
+            }
+            Message::ToggleSelectionFilterType(name) => {
+                let f = &mut self.tabs[self.active_tab].scene.selection_filter;
+                if !f.remove(&name) {
+                    f.insert(name);
+                }
+                Task::none()
+            }
             Message::ToggleUnitsPopup => {
                 self.units_popup_open ^= true;
                 Task::none()

src/app/view.rs

@@ -1173,6 +1173,7 @@ impl OpenCADStudio {
                         tab.scene.is_isolation_active(),
                         tab.scene.transparency_display,
                         self.quick_properties,
+                        tab.scene.selection_filter_active(),
                         &self.statusbar_config,
                     )
                 })
@@ -1232,6 +1233,21 @@ impl OpenCADStudio {
             iced::widget::Space::new().width(0).height(0).into()
         };
 
+        let sel_filter_layer: Element<'_, Message> = if self.selection_filter_popup_open {
+            let types: Vec<String> = tab
+                .scene
+                .entity_type_names_in_layout()
+                .into_iter()
+                .map(|s| s.to_string())
+                .collect();
+            crate::ui::selection_filter_popup::selection_filter_popup_overlay(
+                types,
+                &tab.scene.selection_filter,
+            )
+        } else {
+            iced::widget::Space::new().width(0).height(0).into()
+        };
+
         let dropdown_layer: Element<'_, Message> = self
             .ribbon
             .dropdown_overlay(
@@ -1270,6 +1286,7 @@ impl OpenCADStudio {
             statusbar_menu_layer,
             units_layer,
             isolate_layer,
+            sel_filter_layer,
             dropdown_layer,
             layout_ctx_layer,
             qselect_layer,

src/scene/mod.rs

@@ -556,6 +556,9 @@ pub struct Scene {
     /// Whether entity transparency is honoured on screen. When false the
     /// wire shader forces every line opaque (a uniform toggle, no retessellate).
     pub transparency_display: bool,
+    /// Selection filter: entity-type names excluded from interactive picking.
+    /// Empty = every type is selectable.
+    pub selection_filter: HashSet<String>,
     /// In-progress preview wires while a command is active (rubber-band + object ghosts).
     pub preview_wires: Vec<WireModel>,
     /// Committed-segment wire drawn during multi-point commands (normal colour).
@@ -702,6 +705,7 @@ impl Scene {
             selected: HashSet::new(),
             hidden: HashSet::new(),
             transparency_display: true,
+            selection_filter: HashSet::new(),
             preview_wires: vec![],
             interim_wire: None,
             camera_generation: 0,
@@ -4267,6 +4271,25 @@ impl Scene {
         names.into_iter().collect()
     }
 
+    /// True when `handle`'s entity type is allowed by the selection filter.
+    /// The filter stores excluded type names; empty = everything allowed.
+    pub fn passes_selection_filter(&self, handle: Handle) -> bool {
+        if self.selection_filter.is_empty() {
+            return true;
+        }
+        match self.document.get_entity(handle) {
+            Some(e) => !self
+                .selection_filter
+                .contains(crate::entities::traits::entity_type_name(e)),
+            None => true,
+        }
+    }
+
+    /// True when the selection filter is excluding at least one type.
+    pub fn selection_filter_active(&self) -> bool {
+        !self.selection_filter.is_empty()
+    }
+
     /// Returns the list of `(field, label)` pairs the Quick Select
     /// "Properties" dropdown should show given the current type filter:
     ///

src/ui/mod.rs

@@ -19,6 +19,7 @@ pub mod plotstyle;
 pub mod properties;
 pub mod ribbon;
 pub mod scale_popup;
+pub mod selection_filter_popup;
 pub mod shortcuts;
 pub mod snap_popup;
 pub mod statusbar;

src/ui/selection_filter_popup.rs

@@ -0,0 +1,131 @@
+//! Selection-filter type picker — choose which entity types are selectable.
+//! A checked row means that type can be picked; unchecking it excludes the
+//! type from interactive selection. Opened from the FILTER status pill.
+
+use std::collections::HashSet;
+
+use iced::widget::{button, column, container, mouse_area, row, text};
+use iced::{Background, Border, Color, Element, Fill, Length, Padding, Theme};
+
+use crate::app::Message;
+
+/// Full-screen overlay: transparent click-catcher + type list pinned
+/// bottom-right, above the status bar.
+///
+/// - `types`: entity-type names present in the current layout.
+/// - `excluded`: types currently filtered out (unchecked).
+pub fn selection_filter_popup_overlay(
+    types: Vec<String>,
+    excluded: &HashSet<String>,
+) -> Element<'static, Message> {
+    let rows: Vec<Element<'static, Message>> = if types.is_empty() {
+        vec![empty_row()]
+    } else {
+        types
+            .into_iter()
+            .map(|name| {
+                let included = !excluded.contains(&name);
+                type_row(name, included)
+            })
+            .collect()
+    };
+
+    let panel = container(column(rows))
+        .style(|_: &Theme| container::Style {
+            background: Some(Background::Color(PANEL_BG)),
+            border: Border {
+                color: PANEL_BORDER,
+                width: 1.0,
+                radius: 3.0.into(),
+            },
+            ..Default::default()
+        })
+        .width(Length::Fixed(160.0));
+
+    let positioned = container(panel)
+        .align_right(Fill)
+        .align_bottom(Fill)
+        .padding(Padding {
+            bottom: 27.0,
+            right: 4.0,
+            top: 0.0,
+            left: 0.0,
+        })
+        .width(Fill)
+        .height(Fill);
+
+    mouse_area(positioned)
+        .on_press(Message::CloseSelectionFilterPopup)
+        .into()
+}
+
+fn type_row(name: String, included: bool) -> Element<'static, Message> {
+    let check = text(if included { "✓" } else { "  " })
+        .size(11)
+        .color(if included { CHECK_COLOR } else { Color::TRANSPARENT })
+        .width(Length::Fixed(14.0));
+
+    let lbl = text(name.clone())
+        .size(11)
+        .color(if included { LABEL_ON } else { LABEL_OFF });
+
+    let content = row![check, lbl].spacing(6).align_y(iced::Center);
+
+    button(content)
+        .on_press(Message::ToggleSelectionFilterType(name))
+        .style(|_: &Theme, status| button::Style {
+            background: Some(Background::Color(match status {
+                button::Status::Hovered => ROW_HOVER,
+                _ => Color::TRANSPARENT,
+            })),
+            ..Default::default()
+        })
+        .width(Fill)
+        .padding([4, 10])
+        .into()
+}
+
+fn empty_row() -> Element<'static, Message> {
+    container(text("No objects").size(11).color(LABEL_OFF))
+        .padding([4, 10])
+        .into()
+}
+
+// ── Colours ───────────────────────────────────────────────────────────────
+
+const PANEL_BG: Color = Color {
+    r: 0.15,
+    g: 0.15,
+    b: 0.15,
+    a: 1.0,
+};
+const PANEL_BORDER: Color = Color {
+    r: 0.32,
+    g: 0.32,
+    b: 0.32,
+    a: 1.0,
+};
+const ROW_HOVER: Color = Color {
+    r: 0.22,
+    g: 0.22,
+    b: 0.22,
+    a: 1.0,
+};
+const CHECK_COLOR: Color = Color {
+    r: 0.35,
+    g: 0.75,
+    b: 1.00,
+    a: 1.0,
+};
+const LABEL_ON: Color = Color {
+    r: 0.92,
+    g: 0.92,
+    b: 0.92,
+    a: 1.0,
+};
+const LABEL_OFF: Color = Color {
+    r: 0.6,
+    g: 0.6,
+    b: 0.6,
+    a: 1.0,
+};

src/ui/statusbar.rs

@@ -65,6 +65,8 @@ impl StatusBar {
         transparency_display: bool,
         // Whether the Quick Properties floating panel is enabled.
         quick_properties: bool,
+        // True when the selection filter is excluding at least one type.
+        selection_filter_active: bool,
         // Which pills the user has chosen to show on the bar.
         config: &'a StatusBarConfig,
     ) -> Element<'a, Message> {
@@ -201,6 +203,16 @@ impl StatusBar {
                 "Quick Properties\nFloating panel on selection",
             ));
         }
+        if vis(StatusPill::SelFilter) {
+            right_status = right_status.push(tip(
+                toggle_pill(
+                    "FILTER",
+                    selection_filter_active,
+                    Message::ToggleSelectionFilterPopup,
+                ),
+                "Selection Filtering\nLimit which object types can be picked",
+            ));
+        }
         if vis(StatusPill::Vp) && !vp_label.is_empty() {
             right_status = right_status.push(tip(
                 status_pill(vp_label).into(),

src/ui/statusbar_config.rs

@@ -26,6 +26,7 @@ pub enum StatusPill {
     Transparency,
     Isolate,
     QuickProps,
+    SelFilter,
     Vp,
     CleanScreen,
 }
@@ -49,6 +50,7 @@ impl StatusPill {
         StatusPill::Transparency,
         StatusPill::Isolate,
         StatusPill::QuickProps,
+        StatusPill::SelFilter,
         StatusPill::Vp,
         StatusPill::CleanScreen,
     ];
@@ -71,6 +73,7 @@ impl StatusPill {
             StatusPill::Transparency => "transparency",
             StatusPill::Isolate => "isolate",
             StatusPill::QuickProps => "quickprops",
+            StatusPill::SelFilter => "selfilter",
             StatusPill::Vp => "vp",
             StatusPill::CleanScreen => "cleanscreen",
         }
@@ -94,6 +97,7 @@ impl StatusPill {
             StatusPill::Transparency => "Show Transparency",
             StatusPill::Isolate => "Isolate Objects",
             StatusPill::QuickProps => "Quick Properties",
+            StatusPill::SelFilter => "Selection Filtering",
             StatusPill::Vp => "Viewport Count",
             StatusPill::CleanScreen => "Clean Screen",
         }