Merge PR #1110: expose selection settings

# Conflicts:
#	src/app/mod.rs
#	src/app/properties.rs
#	src/app/settings.rs
#	src/app/update/file.rs
#	src/app/view/modal.rs
#	src/ui/window/options.rs

src/app/update/file.rs

@@ -367,6 +367,7 @@ impl OpenCADStudio {
             pick_box: self.pick_box,
             double_click_block_refedit: self.double_click_block_refedit,
             double_click_block_attedit: self.double_click_block_attedit,
+            grip_object_limit: self.grip_object_limit,
             cursor_type: self.cursor_type,
             crosshair_color: self.crosshair_color,
             lineweight_display_scale: self.lineweight_display_scale,
@@ -422,6 +423,7 @@ impl OpenCADStudio {
         self.pick_box = s.pick_box.clamp(0, 50);
         self.double_click_block_refedit = s.double_click_block_refedit;
         self.double_click_block_attedit = s.double_click_block_attedit;
+        self.grip_object_limit = s.grip_object_limit.clamp(0, 32767);
         self.cursor_type = s.cursor_type;
         self.crosshair_color = s.crosshair_color;
         self.crosshair_color_input = s

src/app/update/mod.rs

@@ -6137,6 +6137,48 @@ impl OpenCADStudio {
                 Task::none()
             }
 
+            Message::GripObjectLimitChanged(limit) => {
+                self.grip_object_limit = limit.clamp(0, 32767);
+                self.persist_settings_if_changed();
+                Task::none()
+            }
+
+            Message::SelectionEffectToggled(enabled) => {
+                self.model_space.selection_effect = enabled;
+                self.sync_model_space_theme(false);
+                self.persist_settings_if_changed();
+                Task::none()
+            }
+
+            // SELECTIONPREVIEW is a bitmask and the two checkboxes own one bit
+            // each: 1 = rollover while idle, 2 = rollover during a command.
+            Message::SelectionPreviewIdleToggled(enabled) => {
+                self.model_space.selection_preview =
+                    set_preview_bit(self.model_space.selection_preview, 1, enabled);
+                self.persist_settings_if_changed();
+                Task::none()
+            }
+
+            Message::SelectionPreviewCommandToggled(enabled) => {
+                self.model_space.selection_preview =
+                    set_preview_bit(self.model_space.selection_preview, 2, enabled);
+                self.persist_settings_if_changed();
+                Task::none()
+            }
+
+            // "Use Shift to add" is the inverse of PICKADD.
+            Message::ShiftToAddToggled(shift_to_add) => {
+                self.pick_add = !shift_to_add;
+                self.persist_settings_if_changed();
+                Task::none()
+            }
+
+            Message::PickDragRectToggled(rectangle) => {
+                self.pick_drag_rect = rectangle;
+                self.persist_settings_if_changed();
+                Task::none()
+            }
+
             Message::RestoreSelectionVisualDefaults => {
                 self.model_space.selection_area = true;
                 self.model_space.selection_opacity = 12;
@@ -6149,6 +6191,10 @@ impl OpenCADStudio {
                 self.model_space.grip_color = 0;
                 self.model_space.grip_hot = 0;
                 self.model_space.grip_hover = 0;
+                // The button restores the *visual* defaults, which is why the
+                // grip limit is here and PICKADD / PICKDRAG are not — those are
+                // how selection behaves, not how it looks.
+                self.grip_object_limit = crate::app::settings::DEFAULT_GRIP_OBJECT_LIMIT;
                 self.sync_model_space_theme(false);
                 self.persist_settings_if_changed();
                 Task::none()
@@ -8661,3 +8707,12 @@ mod free_text_entry_tests {
         assert_eq!(app.text_entry_mode(), TextEntryMode::Command);
     }
 }
+
+/// Set or clear one bit of `SELECTIONPREVIEW`.
+fn set_preview_bit(current: u8, bit: u8, enabled: bool) -> u8 {
+    if enabled {
+        current | bit
+    } else {
+        current & !bit
+    }
+}

src/app/update/viewport.rs

@@ -5778,3 +5778,57 @@ properties={:.1}ms picked={}",
         Task::none()
     }
 }
+
+#[cfg(test)]
+mod selection_preview_tests {
+    use super::*;
+    use crate::app::{HoverDwell, OpenCADStudio, HOVER_DWELL_MS};
+
+    /// Drive one settled rollover pick over a line and report what the scene
+    /// ended up highlighting.
+    fn rollover_hits(preview: u8) -> bool {
+        let mut app = OpenCADStudio::new_for_test();
+        app.automation_op(r#"{"op":"new"}"#);
+        let i = app.active_tab;
+        app.model_space.selection_preview = preview;
+        let _ = app.run_command_line("LINE 0,0 10,10");
+        app.tabs[i].scene.selection.borrow_mut().vp_size = (800.0, 600.0);
+        let _ = app.run_command_line("ZOOM EXTENTS");
+
+        // The pick only runs once the cursor has been still for the dwell
+        // window, so the arming timestamp is backdated past it.
+        app.hover_dwell = Some(HoverDwell {
+            last_move_at: Instant::now()
+                - std::time::Duration::from_millis(HOVER_DWELL_MS as u64 * 2),
+            point: iced::Point::new(400.0, 300.0),
+            tile_size: (800.0, 600.0),
+            tab: i,
+        });
+        let _ = app.on_hover_dwell_tick();
+        app.tabs[i].scene.hover_highlight.is_some()
+    }
+
+    /// Bit 1 of `SELECTIONPREVIEW` is the rollover that runs with no command
+    /// active, and the Options card gives it a checkbox. The config comment
+    /// used to describe the bits the wrong way round, so which bit does what
+    /// is worth asserting rather than reading.
+    #[test]
+    fn the_idle_rollover_follows_bit_one() {
+        assert!(
+            rollover_hits(1),
+            "bit 1 set: the line under the cursor must be highlighted",
+        );
+        assert!(
+            rollover_hits(3),
+            "both bits set: still highlighted",
+        );
+        assert!(
+            !rollover_hits(0),
+            "preview off: nothing may be highlighted",
+        );
+        assert!(
+            !rollover_hits(2),
+            "only the in-command bit: the idle rollover stays off",
+        );
+    }
+}