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/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",
         }