Add named parameters, UI scale setting, OPTIONS/OP dispatch, and help manual

Named parameters (docs/named_parameters_design.md, stages 3-4):
- ParameterTable (src/scene/named_parameters.rs): a document-wide table of
  named formulas, each resolved through a shared expression evaluator with
  cross-parameter references, cycle detection, and division-by-zero/parse
  error reporting. SketchConstraint::driving_param becomes DrivingValue
  (Literal | Named) instead of a bare f64, resolved at solve time by
  sketch_solve::build_constraint via Scene::named_parameters.
- Persistence (src/scene/named_parameters_persist.rs): same lazy XRecord
  model sketch_persist.rs already established, synced around open/save.
  Bumps the sketch-constraint XRecord's own format version (1 -> 2) since
  DrivingValue's shape doesn't line up with a version-1 blob's bytes.
- PARAMETERS command and its editor (src/ui/window/named_parameters.rs):
  add/remove/edit rows, live validation, duplicate-name detection: Apply
  defines the table and re-solves every constraint scope with a
  named-parameter-driven constraint (command_driver.rs). Distance/Angle
  constraint prompts (modules/draw/constrain/value.rs) now accept either a
  literal or an existing parameter's name, mirroring how the constraint's
  own value prompt already worked.
- Undo scope-down carried over from this project's own established pattern
  (constraint-system stage 9): the geometry an Apply moves is one undo
  step, but the parameter table edit itself has no undo entry yet — a
  documented follow-up, not a silent gap.

UI scale setting (src/app/settings.rs, app/mod.rs, ui/window/options.rs):
  a whole-interface scale percentage (50-200%), wired directly into iced's
  own per-window scale_factor hook rather than per-panel font-size
  plumbing, so it applies immediately to every panel, dialog, and the
  ribbon at once. Persisted alongside the existing lineweight-display-scale
  setting.

OPTIONS/OP command dispatch (app/commands/view.rs, app/commands/mod.rs):
  OPTIONS was registered for autocomplete but had no dispatch arm — the
  Start-tab welcome screen's own button was the only way to reach it.
  Found live-testing the UI-scale setting, unrelated to that feature
  itself. "OP" is AutoCAD's own short alias.

help/: a new self-contained static user-help manual (manual.md as the
authored source, tools/build_help.py splits it into the committed static
HTML pages plus search index) — not yet wired into the application.

64 new/updated tests across the named-parameters and constraint-prompt
changes.

Co-Authored-By: Claude Sonnet 5 <[email protected]>

src/app/automation.rs

@@ -302,6 +302,7 @@ impl OpenCADStudio {
                 let i = self.active_tab;
                 self.tabs[i].scene.document = acadrust::CadDocument::new();
                 self.tabs[i].scene.sketch_constraints.clear();
+                self.tabs[i].scene.named_parameters = crate::scene::named_parameters::ParameterTable::new();
                 self.tabs[i].scene.deselect_all();
                 self.tabs[i].current_path = None;
                 // The headless session starts on the welcome (Start) tab, which
@@ -331,6 +332,7 @@ impl OpenCADStudio {
                         let i = self.active_tab;
                         self.tabs[i].scene.document = doc;
                         self.tabs[i].scene.load_sketch_constraints_from_document();
+                        self.tabs[i].scene.load_named_parameters_from_document();
                         self.tabs[i].scene.deselect_all();
                         crate::app::style_ops::ensure_standard_styles(
                             &mut self.tabs[i].scene.document,
@@ -1063,6 +1065,7 @@ mod tests {
             "CHANGELOG",
             "CUI",
             "ALIASEDIT",
+            "OPTIONS",
         ];
         for cmd in standalone {
             assert!(

src/app/command_driver.rs

@@ -951,6 +951,81 @@ impl OpenCADStudio {
         self.push_sketch_constraints_history(i, label, scope, constraints_before);
     }
 
+    /// PARAMETERS' Apply button (`docs/named_parameters_design.md` stage 4):
+    /// rebuilds the active tab's `Scene::named_parameters` from the
+    /// editor's working buffer, reports any row that failed to validate via
+    /// the command line, and re-solves every scope with a constraint driven
+    /// by a named parameter — the entire point of a *named* parameter is
+    /// that editing it ripples to whatever references it, the same way
+    /// editing a constraint's literal value already does.
+    ///
+    /// **Deliberate scope-down, matching this project's established
+    /// treatment of undo-granularity questions** (design doc §5 open
+    /// question 3, and the sibling constraint-system project's stage 9): the
+    /// geometry this ripple moves is bracketed into one undo step below
+    /// (same `begin_undo`/`bump_entities`/`commit_undo_delta` pattern
+    /// `resolve_one_sketch_conflict` above uses), but the parameter *table*
+    /// edit itself has no undo entry of its own yet — that would need a new
+    /// `HistorySnapshot` variant mirroring `SketchConstraints`
+    /// (`push_sketch_constraints_history`). Left for a follow-up, not
+    /// silently dropped: undoing after an Apply undoes the geometry it
+    /// moved, not the parameter values themselves.
+    pub(super) fn apply_named_parameter_editor_rows(&mut self) {
+        let i = self.active_tab;
+        // A name shared by more than one row can't be resolved by picking
+        // one arbitrarily (`ParameterTable::set` would just let the last
+        // one silently win) -- refuse every row sharing that name up front,
+        // same as `named_parameters::preview`'s live check.
+        let duplicates = crate::ui::window::named_parameters::duplicate_name_rows(&self.named_parameter_editor_rows);
+        let mut table = crate::scene::named_parameters::ParameterTable::new();
+        let mut failed = 0usize;
+        for (idx, row) in self.named_parameter_editor_rows.iter().enumerate() {
+            let name = row.name.trim();
+            if name.is_empty() || duplicates.contains(&idx) {
+                continue;
+            }
+            if let Err(e) = table.set(name, row.formula.trim()) {
+                self.command_line.push_error(crate::tf!("Parameter '{}': {}", name, e).as_ref());
+                failed += 1;
+            }
+        }
+        if !duplicates.is_empty() {
+            self.command_line.push_error(crate::tf!("{} row(s) skipped: duplicate parameter name.", duplicates.len()).as_ref());
+            failed += duplicates.len();
+        }
+        let param_count = table.len();
+        self.tabs[i].scene.named_parameters = table;
+
+        // The whole table just changed, not one isolated value, so there is
+        // no cheaper "which handles actually moved" test worth doing here —
+        // re-solve every scope with a constraint driven by *any* named
+        // parameter (mirrors `solve_scope`'s own "full rebuild, not
+        // incremental" philosophy).
+        let touched: Vec<Handle> = self.tabs[i]
+            .scene
+            .sketch_constraints
+            .iter()
+            .flat_map(|set| set.constraints.iter())
+            .filter(|c| c.enabled && matches!(c.driving_param, Some(crate::scene::named_parameters::DrivingValue::Named(_))))
+            .flat_map(|c| c.refs.iter().map(|r| r.entity))
+            .collect();
+
+        if !touched.is_empty() {
+            let pending = self.begin_undo(i, "Apply named parameters", touched.len(), true);
+            let changes: Vec<(Handle, crate::scene::ChangeKind)> =
+                touched.into_iter().map(|h| (h, crate::scene::ChangeKind::Modified)).collect();
+            self.tabs[i].scene.bump_entities(&changes);
+            if let Some(pd) = pending {
+                self.commit_undo_delta(i, pd);
+            }
+        }
+
+        self.tabs[i].dirty = true;
+        if failed == 0 {
+            self.command_line.push_info(crate::tf!("{} parameter(s) applied.", param_count).as_ref());
+        }
+    }
+
     fn apply_cmd_result_inner(&mut self, result: CmdResult) -> Task<Message> {
         let i = self.active_tab;
         let preserve_commit_layer = self.tabs[i]
@@ -6075,6 +6150,93 @@ mod sketch_constraint_undo_tests {
         assert_eq!(set.constraints.len(), 2, "undo should restore the removed constraint");
     }
 
+    /// `named_parameters_design.md` stage 4: applying the PARAMETERS editor's
+    /// working buffer both defines the parameter and re-solves whatever
+    /// constraint already references it by name — the entire point of a
+    /// *named* parameter, not just data plumbing.
+    #[test]
+    fn applying_named_parameter_rows_defines_and_resolves_referencing_constraints() {
+        let mut app = OpenCADStudio::new_for_test();
+        let _ = app.automation_op(r#"{"op":"new"}"#);
+        let line = add_line(&mut app, 0.0, 0.0, 10.0, 0.0);
+
+        // The constraint is added *before* the parameter exists -- allowed,
+        // same as `ParameterTable::set`'s own forward-reference tolerance;
+        // it just doesn't resolve to anything until the parameter is defined.
+        let _ = app.apply_cmd_result(CmdResult::AddSketchConstraint {
+            kind: ConstraintKind::Distance,
+            refs: vec![SketchRef::point(line, 0), SketchRef::point(line, 1)],
+            driving_param: Some(crate::scene::named_parameters::DrivingValue::Named("target_len".to_string())),
+            label: "Distance constraint",
+        });
+
+        app.named_parameter_editor_rows =
+            vec![crate::ui::window::named_parameters::ParamEditorRow { name: "target_len".to_string(), formula: "8".to_string() }];
+        app.apply_named_parameter_editor_rows();
+
+        assert_eq!(app.tabs[app.active_tab].scene.named_parameters().resolve("target_len"), Ok(8.0));
+        let (start, end) = match app.tabs[app.active_tab].scene.document.get_entity(line) {
+            Some(acadrust::EntityType::Line(l)) => (l.start, l.end),
+            other => panic!("expected a Line, got {other:?}"),
+        };
+        let len = ((end.x - start.x).powi(2) + (end.y - start.y).powi(2)).sqrt();
+        assert!((len - 8.0).abs() < 1e-6, "length should track the applied parameter, got {len}");
+
+        // Redefining the parameter and re-applying should ripple again.
+        app.named_parameter_editor_rows[0].formula = "3".to_string();
+        app.apply_named_parameter_editor_rows();
+        let (start, end) = match app.tabs[app.active_tab].scene.document.get_entity(line) {
+            Some(acadrust::EntityType::Line(l)) => (l.start, l.end),
+            other => panic!("expected a Line, got {other:?}"),
+        };
+        let len = ((end.x - start.x).powi(2) + (end.y - start.y).powi(2)).sqrt();
+        assert!((len - 3.0).abs() < 1e-6, "length should track the redefined parameter, got {len}");
+    }
+
+    /// A row that fails to validate (here, a formula that doesn't parse)
+    /// must not silently vanish or corrupt the table: it's reported as an
+    /// error and simply isn't added, while a valid row alongside it still
+    /// commits — the same isolate-the-failure treatment
+    /// `ParameterTable::resolve_all` already gives a bad reference.
+    #[test]
+    fn applying_a_row_with_a_malformed_formula_reports_an_error_and_keeps_the_good_row() {
+        let mut app = OpenCADStudio::new_for_test();
+        let _ = app.automation_op(r#"{"op":"new"}"#);
+
+        app.named_parameter_editor_rows = vec![
+            crate::ui::window::named_parameters::ParamEditorRow { name: "good".to_string(), formula: "10".to_string() },
+            crate::ui::window::named_parameters::ParamEditorRow { name: "bad".to_string(), formula: "1 +".to_string() },
+        ];
+        app.apply_named_parameter_editor_rows();
+
+        assert_eq!(app.tabs[app.active_tab].scene.named_parameters().resolve("good"), Ok(10.0));
+        assert!(!app.tabs[app.active_tab].scene.named_parameters().contains("bad"), "a malformed row must not be added");
+        assert!(
+            app.command_line.history.iter().any(|e| e.kind == crate::ui::command_line::EntryKind::Error),
+            "a malformed row must be reported as an error, not silently dropped"
+        );
+    }
+
+    /// Two rows typed with the same name must not silently collapse into
+    /// "whichever `set` call happens last wins" — both are refused, and an
+    /// unrelated row still commits normally.
+    #[test]
+    fn applying_rows_with_a_duplicate_name_refuses_both_and_keeps_the_unrelated_row() {
+        let mut app = OpenCADStudio::new_for_test();
+        let _ = app.automation_op(r#"{"op":"new"}"#);
+
+        app.named_parameter_editor_rows = vec![
+            crate::ui::window::named_parameters::ParamEditorRow { name: "x".to_string(), formula: "1".to_string() },
+            crate::ui::window::named_parameters::ParamEditorRow { name: "x".to_string(), formula: "2".to_string() },
+            crate::ui::window::named_parameters::ParamEditorRow { name: "y".to_string(), formula: "3".to_string() },
+        ];
+        app.apply_named_parameter_editor_rows();
+
+        assert!(!app.tabs[app.active_tab].scene.named_parameters().contains("x"), "a duplicated name must not be added at all");
+        assert_eq!(app.tabs[app.active_tab].scene.named_parameters().resolve("y"), Ok(3.0));
+        assert!(app.command_line.history.iter().any(|e| e.kind == crate::ui::command_line::EntryKind::Error));
+    }
+
     /// Design doc §6.1's manual Coincident UI: two picks landing on two
     /// different lines' endpoints should resolve to a real `SketchRef` pair
     /// and add a Coincident constraint — the same `AddCoincidentConstraint`

src/app/commands/mod.rs

@@ -292,6 +292,8 @@ pub fn start_allowed(cmd: &str) -> bool {
             | "PERF"
             | "CUI"
             | "ALIASEDIT"
+            | "OPTIONS"
+            | "OP"
             | "CUILOAD"
             | "CUIIMPORT"
     )
@@ -312,6 +314,7 @@ inventory::submit!(crate::command::CommandRegistration {
         "CLEANSCREEN",
         "CUI",
         "DSETTINGS",
+        "PARAMETERS",
         "GRID",
         "ISODRAFT",
         "ISOPLANE",

src/app/commands/view.rs

@@ -240,6 +240,25 @@ impl OpenCADStudio {
                 return Some(Task::done(Message::AliasEditorOpen));
             }
 
+            // ── OPTIONS — app preferences dialog ────────────────────────────
+            // Registered for autocomplete (`commands/mod.rs`'s "one-shot
+            // commands" list) but had no actual dispatch arm anywhere — the
+            // Start-tab welcome screen's "Options" button emits
+            // `Message::OptionsOpen` directly and was the only way to reach
+            // it. Found while live-testing the new UI-scale setting (nothing
+            // to do with that feature itself, just discovered along the
+            // way). "OP" is AutoCAD's own short alias for this command.
+            "OPTIONS" | "OP" => {
+                return Some(Task::done(Message::OptionsOpen));
+            }
+
+            // ── PARAMETERS — named-parameter/expression table editor ───────
+            // `docs/named_parameters_design.md` stage 4. AutoCAD's own
+            // command name for the equivalent feature (Parameters Manager).
+            "PARAMETERS" => {
+                return Some(Task::done(Message::NamedParametersOpen));
+            }
+
             // ── CUI — keyboard shortcut / key-binding editor ───────────────
             "CUI" => {
                 return Some(Task::done(Message::ShortcutsPanelOpen));

src/app/mod.rs

@@ -504,6 +504,12 @@ pub(super) struct OpenCADStudio {
     crosshair_color_input: String,
     /// Model-space lineweight preview scale, in percent (25..=200).
     lineweight_display_scale: i32,
+    /// Whole-interface scale, in percent (50..=200) — drives iced's own
+    /// per-window `scale_factor` (`run`'s `.scale_factor(...)` hook), so it
+    /// resizes every panel, dialog, the ribbon, and their text uniformly
+    /// rather than needing a separate font-size knob threaded through each
+    /// panel's own view code.
+    ui_scale: i32,
     /// Isometric drafting state and active axis pair.
     isometric_drafting: bool,
     iso_plane: settings::IsoPlane,
@@ -1018,6 +1024,15 @@ pub(super) struct OpenCADStudio {
     /// edited. Seeded from `command_aliases` on open, committed back on close.
     alias_editor_rows: Vec<(String, String)>,
 
+    // ── Named Parameters (docs/named_parameters_design.md, stage 4) ────────
+    /// Working buffer for the PARAMETERS modal. Unlike `alias_editor_rows`,
+    /// this isn't a copy of a separate app-level store — the real state
+    /// lives per-document at `Scene::named_parameters`; this buffer is
+    /// seeded from the active tab's table on open and only written back to
+    /// it on Apply (`apply_named_parameter_editor_rows`,
+    /// `src/app/named_parameters.rs`).
+    named_parameter_editor_rows: Vec<crate::ui::window::named_parameters::ParamEditorRow>,
+
     // ── Layout Manager Panel ──────────────────────────────────────────────
     layout_manager_selected: String,
     layout_manager_rename_buf: String,
@@ -1695,6 +1710,7 @@ pub enum ModalKind {
     AttributeEditor,
     LayerDeleteWarning,
     Aliases,
+    NamedParameters,
     ScaleManager,
     /// Add / remove the annotation scales a single selected object has a
     /// per-object representation for.
@@ -1937,6 +1953,8 @@ pub enum Message {
     CursorTypeChanged(settings::CursorType),
     /// Set the model-space lineweight preview scale from Options.
     LineweightDisplayScaleChanged(i32),
+    /// Set the whole-interface scale (`ui_scale`) from Options.
+    UiScaleChanged(i32),
     /// Set the ribbon's large-button icon-label font size from Options.
     RibbonLabelFontSizeChanged(i32),
     /// Set the ribbon's panel-title ("Draw", "Modify", …) font size from Options.
@@ -2706,6 +2724,24 @@ pub enum Message {
     AliasEditorRemove(usize),
     /// Commit the edited rows to the alias table (Apply button); stays open.
     AliasEditorApply,
+    // ── Named Parameters (PARAMETERS) ───────────────────────────────────
+    /// Open the named-parameter editor, seeding rows from the active tab's
+    /// `Scene::named_parameters`.
+    NamedParametersOpen,
+    /// Live edit of the name or formula in row `idx`.
+    NamedParametersInput {
+        idx: usize,
+        field: crate::ui::window::named_parameters::ParamField,
+        value: String,
+    },
+    /// Append a blank parameter row.
+    NamedParametersAdd,
+    /// Remove parameter row `idx`.
+    NamedParametersRemove(usize),
+    /// Commit the edited rows to `Scene::named_parameters` (Apply button)
+    /// and re-solve every constraint that reads a named parameter; stays
+    /// open.
+    NamedParametersApply,
     // ── About window ────────────────────────────────────────────────────
     AboutOpen,
     /// Close whatever in-canvas modal dialog is open (Plan B).
@@ -3378,6 +3414,7 @@ impl OpenCADStudio {
             crosshair_color: None,
             crosshair_color_input: String::new(),
             lineweight_display_scale: 100,
+            ui_scale: 100,
             isometric_drafting: false,
             iso_plane: settings::IsoPlane::Left,
             snap_angle_deg: 0.0,
@@ -3579,6 +3616,7 @@ impl OpenCADStudio {
             // Command aliases (populated from ocad.pgp just after construction)
             command_aliases: rustc_hash::FxHashMap::default(),
             alias_editor_rows: Vec::new(),
+            named_parameter_editor_rows: Vec::new(),
             // Layout Manager
             layout_manager_selected: "Model".to_string(),
             layer_state_selected: None,
@@ -3978,6 +4016,7 @@ pub fn run() -> iced::Result {
         ..iced::Settings::default()
     })
     .subscription(OpenCADStudio::subscription)
+    .scale_factor(|state: &OpenCADStudio, _window: window::Id| state.ui_scale as f32 / 100.0)
     .title(|state: &OpenCADStudio, window_id: window::Id| {
         let _ = window_id; // all dialogs are in-canvas modals now
         if let Some(tab) = state.tabs.get(state.active_tab) {
@@ -4022,6 +4061,7 @@ pub fn run_web() -> iced::Result {
         OpenCADStudio::view_main,
     )
     .subscription(OpenCADStudio::subscription)
+    .scale_factor(|state: &OpenCADStudio| state.ui_scale as f32 / 100.0)
     .title(|_state: &OpenCADStudio| {
         concat!("Open CAD Studio ", env!("OCS_APP_VERSION")).to_string()
     })

src/app/settings.rs

@@ -166,6 +166,14 @@ pub struct UserSettings {
     pub crosshair_color: Option<[u8; 3]>,
     /// Model-space lineweight preview scale as a percentage.
     pub lineweight_display_scale: i32,
+    /// Whole-interface scale, as a percentage — every panel, dialog, the
+    /// ribbon, and their text, not just one widget's font size. Wired
+    /// straight into iced's own per-window `scale_factor` hook
+    /// (`OpenCADStudio::run`), so a change takes effect immediately with no
+    /// per-panel plumbing needed. Relies on the struct-level `#[serde(default)]`
+    /// (via `impl Default` below) to backfill this field for a config file
+    /// saved before this setting existed, same as every other field here.
+    pub ui_scale: i32,
     /// Isometric drafting changes the grid and crosshair to the active axis pair.
     pub isometric_drafting: bool,
     pub iso_plane: IsoPlane,
@@ -310,6 +318,7 @@ impl Default for UserSettings {
             cursor_type: CursorType::Crosshair,
             crosshair_color: None,
             lineweight_display_scale: 100,
+            ui_scale: 100,
             isometric_drafting: false,
             iso_plane: IsoPlane::Left,
             snap_angle_deg: 0.0,

src/app/update/file.rs

@@ -368,6 +368,7 @@ impl OpenCADStudio {
             cursor_type: self.cursor_type,
             crosshair_color: self.crosshair_color,
             lineweight_display_scale: self.lineweight_display_scale,
+            ui_scale: self.ui_scale,
             isometric_drafting: self.isometric_drafting,
             iso_plane: self.iso_plane,
             snap_angle_deg: self.snap_angle_deg,
@@ -425,6 +426,7 @@ impl OpenCADStudio {
             .map(crate::app::config::rgb_to_hex)
             .unwrap_or_default();
         self.lineweight_display_scale = s.lineweight_display_scale.clamp(25, 200);
+        self.ui_scale = s.ui_scale.clamp(50, 200);
         self.isometric_drafting = s.isometric_drafting;
         self.iso_plane = s.iso_plane;
         self.snap_angle_deg = if s.snap_angle_deg.is_finite() {
@@ -1394,6 +1396,9 @@ pub(super) fn on_open_file(&mut self) -> Task<Message> {
                 // Design doc §8 stage 4: read back any persisted sketch
                 // constraint sets right after the document is installed.
                 self.tabs[i].scene.load_sketch_constraints_from_document();
+                // named_parameters_design.md stage 2: same load-time hook,
+                // for the document-wide parameter table.
+                self.tabs[i].scene.load_named_parameters_from_document();
                 self.tabs[i].active_layer = self.tabs[i]
                     .scene
                     .document
@@ -1660,6 +1665,9 @@ pub(super) fn on_open_file(&mut self) -> Task<Message> {
         // Design doc §8 stage 4: write any sketch constraint sets into the
         // document right before it's serialized.
         self.tabs[i].scene.materialize_sketch_constraints_for_save();
+        // named_parameters_design.md stage 2: same save-time hook, for the
+        // document-wide parameter table.
+        self.tabs[i].scene.materialize_named_parameters_for_save();
     }
 
     #[cfg(not(target_arch = "wasm32"))]
@@ -2611,6 +2619,7 @@ pub(super) fn on_open_file(&mut self) -> Task<Message> {
                     self.stamp_header_sysvars(i);
                     self.sync_solid_models_for_save(i);
                     self.tabs[i].scene.materialize_sketch_constraints_for_save();
+                    self.tabs[i].scene.materialize_named_parameters_for_save();
                     let tab_id = self.tabs[i].id;
                     let bounds = crate::ui::wrap_bar::dropdown_bounds(
                         crate::app::view::VIEWPORT_CAPTURE_BOUNDS_ID,

src/app/update/mod.rs

@@ -5861,6 +5861,43 @@ impl OpenCADStudio {
                 Task::none()
             }
 
+            // ── Named Parameters (PARAMETERS) ─────────────────────────────────
+            Message::NamedParametersOpen => {
+                let i = self.active_tab;
+                self.named_parameter_editor_rows = self.tabs[i]
+                    .scene
+                    .named_parameters()
+                    .iter()
+                    .map(|p| crate::ui::window::named_parameters::ParamEditorRow { name: p.name.clone(), formula: p.source.clone() })
+                    .collect();
+                self.active_modal = Some(super::ModalKind::NamedParameters);
+                Task::none()
+            }
+            Message::NamedParametersInput { idx, field, value } => {
+                use crate::ui::window::named_parameters::ParamField;
+                if let Some(row) = self.named_parameter_editor_rows.get_mut(idx) {
+                    match field {
+                        ParamField::Name => row.name = value,
+                        ParamField::Formula => row.formula = value,
+                    }
+                }
+                Task::none()
+            }
+            Message::NamedParametersAdd => {
+                self.named_parameter_editor_rows.push(crate::ui::window::named_parameters::ParamEditorRow::default());
+                Task::none()
+            }
+            Message::NamedParametersRemove(idx) => {
+                if idx < self.named_parameter_editor_rows.len() {
+                    self.named_parameter_editor_rows.remove(idx);
+                }
+                Task::none()
+            }
+            Message::NamedParametersApply => {
+                self.apply_named_parameter_editor_rows();
+                Task::none()
+            }
+
             // ── Options / About windows ───────────────────────────────────
             Message::OptionsOpen => {
                 self.active_modal = Some(super::ModalKind::Options);
@@ -5900,6 +5937,12 @@ impl OpenCADStudio {
                 Task::none()
             }
 
+            Message::UiScaleChanged(value) => {
+                self.ui_scale = value.clamp(50, 200);
+                self.persist_settings_if_changed();
+                Task::none()
+            }
+
             Message::RibbonLabelFontSizeChanged(value) => {
                 self.ribbon.set_label_font_size(value);
                 self.save_config();

src/app/view/modal.rs

@@ -13,6 +13,7 @@ impl OpenCADStudio {
             Some(K::About) => crate::tr!("modal", "about"),
             Some(K::Shortcuts) => crate::tr!("modal", "keyboard-shortcuts"),
             Some(K::Aliases) => crate::tr!("modal", "command-aliases"),
+            Some(K::NamedParameters) => crate::t!("Named Parameters").into_owned(),
             Some(K::Options) => crate::tr!("action", "options"),
             Some(K::FindReplace) => crate::tr!("modal", "find-replace"),
             Some(K::PluginManager) => crate::tr!("modal", "plugin-manager"),
@@ -173,6 +174,19 @@ impl OpenCADStudio {
                     },
                 )
             }
+            super::super::ModalKind::NamedParameters => {
+                sized_flow(
+                    ex,
+                    620,
+                    520,
+                    |flow| {
+                        crate::ui::window::named_parameters::view_window(
+                            &self.named_parameter_editor_rows,
+                            flow,
+                        )
+                    },
+                )
+            }
             super::super::ModalKind::Options => sized_flow(
                 ex,
                 540,
@@ -191,6 +205,7 @@ impl OpenCADStudio {
                         self.crosshair_color,
                         &self.crosshair_color_input,
                         self.lineweight_display_scale,
+                        self.ui_scale,
                         self.ribbon.label_font_size(),
                         self.ribbon.group_title_font_size(),
                         &self.model_space,