feat: MLineStyle manager (MLSTYLE command + dialog)

- MLSTYLE command: LIST, NEW, SET, DEL subcommands
- Multiline Style Manager dialog: style list, element details (offset,
  color, linetype), Set Current / New / Delete buttons
- MLINE/ML command now reads document header.multiline_style to apply
  the current style to newly created MLine entities
- MlineCommand.with_style() constructor for style-aware multiline drawing

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/commands.rs

@@ -392,7 +392,8 @@ impl H7CAD {
 
             "MLINE"|"ML" => {
                 use crate::modules::home::draw::mline::MlineCommand;
-                let cmd_obj = MlineCommand::new();
+                let style = self.tabs[i].scene.document.header.multiline_style.clone();
+                let cmd_obj = MlineCommand::with_style(style);
                 self.command_line.push_info(&cmd_obj.prompt());
                 self.tabs[i].active_cmd = Some(Box::new(cmd_obj));
             }
@@ -2084,6 +2085,115 @@ impl H7CAD {
             }
 
             // ── DimStyle management ───────────────────────────────────────
+            // MLSTYLE — Multiline Style Manager.
+            // Usage:
+            //   MLSTYLE                — open dialog
+            //   MLSTYLE LIST / ?       — list all multiline styles
+            //   MLSTYLE NEW <name>     — create a new style
+            //   MLSTYLE SET <name>     — set current multiline style
+            //   MLSTYLE DEL <name>     — delete a style (not Standard)
+            cmd if cmd == "MLSTYLE" || cmd.starts_with("MLSTYLE ") => {
+                use acadrust::objects::{MLineStyle, ObjectType};
+                let raw_rest = cmd.split_once(' ').map(|(_, r)| r.trim()).unwrap_or("");
+                let parts: Vec<&str> = raw_rest.split_whitespace().collect();
+                let sub = parts.first().map(|s| s.to_uppercase()).unwrap_or_default();
+                match sub.as_str() {
+                    "" | "DIALOG" | "UI" => {
+                        return Task::done(Message::MlStyleDialogOpen);
+                    }
+                    "LIST" | "?" => {
+                        let doc = &self.tabs[i].scene.document;
+                        let current = &doc.header.multiline_style;
+                        let styles: Vec<String> = doc.objects.values()
+                            .filter_map(|o| if let ObjectType::MLineStyle(s) = o { Some(s) } else { None })
+                            .map(|s| {
+                                let cur = if &s.name == current { " (current)" } else { "" };
+                                format!("{}  [{}]{}",
+                                    s.name,
+                                    s.elements.len(),
+                                    cur)
+                            })
+                            .collect();
+                        if styles.is_empty() {
+                            self.command_line.push_output("No multiline styles.");
+                        } else {
+                            self.command_line.push_output(&format!("MLineStyles:\n  {}", styles.join("\n  ")));
+                        }
+                    }
+                    "NEW" | "N" => {
+                        let name = parts.get(1).copied().unwrap_or("").to_string();
+                        if name.is_empty() {
+                            self.command_line.push_error("Usage: MLSTYLE NEW <name>");
+                        } else {
+                            let doc = &self.tabs[i].scene.document;
+                            let exists = doc.objects.values().any(|o| {
+                                matches!(o, ObjectType::MLineStyle(s) if s.name.eq_ignore_ascii_case(&name))
+                            });
+                            if exists {
+                                self.command_line.push_error(&format!("MLSTYLE: '{}' already exists.", name));
+                            } else {
+                                self.push_undo_snapshot(i, "MLSTYLE NEW");
+                                let mut style = MLineStyle::standard();
+                                style.name = name.clone();
+                                let nh = acadrust::Handle::new(self.tabs[i].scene.document.next_handle());
+                                style.handle = nh;
+                                self.tabs[i].scene.document.objects.insert(
+                                    nh, ObjectType::MLineStyle(style)
+                                );
+                                self.tabs[i].dirty = true;
+                                self.command_line.push_output(&format!("MLSTYLE: '{}' created.", name));
+                            }
+                        }
+                    }
+                    "SET" | "S" => {
+                        let name = parts.get(1).copied().unwrap_or("").to_string();
+                        if name.is_empty() {
+                            self.command_line.push_error("Usage: MLSTYLE SET <name>");
+                        } else {
+                            let doc = &self.tabs[i].scene.document;
+                            let exists = doc.objects.values().any(|o| {
+                                matches!(o, ObjectType::MLineStyle(s) if s.name.eq_ignore_ascii_case(&name))
+                            });
+                            if exists {
+                                self.push_undo_snapshot(i, "MLSTYLE SET");
+                                self.tabs[i].scene.document.header.multiline_style = name.clone();
+                                self.tabs[i].dirty = true;
+                                self.command_line.push_output(&format!("MLSTYLE: current style set to '{}'.", name));
+                            } else {
+                                self.command_line.push_error(&format!("MLSTYLE: '{}' not found.", name));
+                            }
+                        }
+                    }
+                    "DEL" | "DELETE" => {
+                        let name = parts.get(1).copied().unwrap_or("").to_string();
+                        if name.is_empty() || name.eq_ignore_ascii_case("Standard") {
+                            self.command_line.push_error("Cannot delete the Standard style.");
+                        } else {
+                            let doc = &self.tabs[i].scene.document;
+                            let handle = doc.objects.iter()
+                                .find_map(|(&h, o)| {
+                                    if let ObjectType::MLineStyle(s) = o {
+                                        if s.name.eq_ignore_ascii_case(&name) { Some(h) } else { None }
+                                    } else { None }
+                                });
+                            if let Some(h) = handle {
+                                self.push_undo_snapshot(i, "MLSTYLE DEL");
+                                self.tabs[i].scene.document.objects.remove(&h);
+                                self.tabs[i].dirty = true;
+                                self.command_line.push_output(&format!("MLSTYLE: '{}' deleted.", name));
+                            } else {
+                                self.command_line.push_error(&format!("MLSTYLE: '{}' not found.", name));
+                            }
+                        }
+                    }
+                    _ => {
+                        self.command_line.push_error(
+                            "Usage: MLSTYLE [LIST|NEW <name>|SET <name>|DEL <name>]"
+                        );
+                    }
+                }
+            }
+
             cmd if cmd == "DIMSTYLE" || cmd == "DDIM" || cmd.starts_with("DIMSTYLE ") || cmd.starts_with("DDIM ") => {
                 use acadrust::tables::DimStyle;
                 let raw_rest = cmd.split_once(' ').map(|(_, r)| r.trim()).unwrap_or("");

src/app/mod.rs

@@ -90,6 +90,10 @@ pub(super) struct H7CAD {
     /// Currently loaded CTB/STB table (None = no override).
     active_plot_style: Option<crate::io::plot_style::PlotStyleTable>,
 
+    // ── MLineStyle Dialog ─────────────────────────────────────────────────
+    mlstyle_open: bool,
+    mlstyle_selected: String,
+
     // ── DimStyle Dialog ───────────────────────────────────────────────────
     dimstyle_open: bool,
     /// Name of the style currently shown in the dialog.
@@ -335,6 +339,13 @@ pub enum Message {
     PlotStyleLoaded(Option<crate::io::plot_style::PlotStyleTable>),
     /// Clear the active plot style table.
     PlotStyleClear,
+    // ── MLineStyle Dialog ─────────────────────────────────────────────────
+    MlStyleDialogOpen,
+    MlStyleDialogClose,
+    MlStyleDialogSelect(String),
+    MlStyleDialogSetCurrent,
+    MlStyleDialogNew,
+    MlStyleDialogDelete,
     // ── DimStyle Dialog ───────────────────────────────────────────────────
     DimStyleDialogOpen,
     DimStyleDialogClose,
@@ -396,6 +407,9 @@ impl H7CAD {
             page_setup_scale: "Fit".to_string(),
             // Plot style
             active_plot_style: None,
+            // MLineStyle dialog
+            mlstyle_open: false,
+            mlstyle_selected: "Standard".to_string(),
             // DimStyle dialog
             dimstyle_open: false,
             dimstyle_selected: "Standard".to_string(),

src/app/update.rs

@@ -2126,6 +2126,98 @@ impl H7CAD {
                 Task::none()
             }
 
+            // ── MLineStyle Dialog ─────────────────────────────────────────────
+            Message::MlStyleDialogOpen => {
+                use acadrust::objects::ObjectType;
+                let i = self.active_tab;
+                let cur = self.tabs[i].scene.document.header.multiline_style.clone();
+                let exists = self.tabs[i].scene.document.objects.values().any(|o| {
+                    matches!(o, ObjectType::MLineStyle(s) if s.name == cur)
+                });
+                self.mlstyle_selected = if exists {
+                    cur
+                } else {
+                    self.tabs[i].scene.document.objects.values()
+                        .find_map(|o| if let ObjectType::MLineStyle(s) = o { Some(s.name.clone()) } else { None })
+                        .unwrap_or_else(|| "Standard".to_string())
+                };
+                self.mlstyle_open = true;
+                Task::none()
+            }
+            Message::MlStyleDialogClose => {
+                self.mlstyle_open = false;
+                Task::none()
+            }
+            Message::MlStyleDialogSelect(name) => {
+                self.mlstyle_selected = name;
+                Task::none()
+            }
+            Message::MlStyleDialogSetCurrent => {
+                use acadrust::objects::ObjectType;
+                let i = self.active_tab;
+                let name = self.mlstyle_selected.clone();
+                let exists = self.tabs[i].scene.document.objects.values().any(|o| {
+                    matches!(o, ObjectType::MLineStyle(s) if s.name == name)
+                });
+                if exists {
+                    self.push_undo_snapshot(i, "MLSTYLE SET");
+                    self.tabs[i].scene.document.header.multiline_style = name.clone();
+                    self.tabs[i].dirty = true;
+                    self.command_line.push_output(&format!("Current multiline style: {}", name));
+                }
+                Task::none()
+            }
+            Message::MlStyleDialogNew => {
+                use acadrust::objects::ObjectType;
+                let i = self.active_tab;
+                // Generate a unique name.
+                let doc = &self.tabs[i].scene.document;
+                let mut n = 1u32;
+                let base = "MLS";
+                let new_name = loop {
+                    let candidate = format!("{}{}", base, n);
+                    let taken = doc.objects.values().any(|o| {
+                        matches!(o, ObjectType::MLineStyle(s) if s.name.eq_ignore_ascii_case(&candidate))
+                    });
+                    if !taken { break candidate; }
+                    n += 1;
+                };
+                self.push_undo_snapshot(i, "MLSTYLE NEW");
+                let mut style = acadrust::objects::MLineStyle::standard();
+                style.name = new_name.clone();
+                let nh = acadrust::Handle::new(self.tabs[i].scene.document.next_handle());
+                style.handle = nh;
+                self.tabs[i].scene.document.objects.insert(nh, ObjectType::MLineStyle(style));
+                self.mlstyle_selected = new_name;
+                self.tabs[i].dirty = true;
+                Task::none()
+            }
+            Message::MlStyleDialogDelete => {
+                use acadrust::objects::ObjectType;
+                let i = self.active_tab;
+                let name = self.mlstyle_selected.clone();
+                if name.eq_ignore_ascii_case("Standard") {
+                    self.command_line.push_error("Cannot delete the Standard style.");
+                    return Task::none();
+                }
+                let handle = self.tabs[i].scene.document.objects.iter()
+                    .find_map(|(&h, o)| {
+                        if let ObjectType::MLineStyle(s) = o {
+                            if s.name == name { Some(h) } else { None }
+                        } else { None }
+                    });
+                if let Some(h) = handle {
+                    self.push_undo_snapshot(i, "MLSTYLE DEL");
+                    self.tabs[i].scene.document.objects.remove(&h);
+                    // Select first remaining style.
+                    self.mlstyle_selected = self.tabs[i].scene.document.objects.values()
+                        .find_map(|o| if let ObjectType::MLineStyle(s) = o { Some(s.name.clone()) } else { None })
+                        .unwrap_or_else(|| "Standard".to_string());
+                    self.tabs[i].dirty = true;
+                }
+                Task::none()
+            }
+
             // ── DimStyle Dialog ───────────────────────────────────────────────
             Message::DimStyleDialogOpen => {
                 let i = self.active_tab;

src/app/view.rs

@@ -227,6 +227,21 @@ impl H7CAD {
             iced::widget::Space::new().width(0).height(0).into()
         };
 
+        let mlstyle_layer: Element<'_, Message> = if self.mlstyle_open {
+            use acadrust::objects::ObjectType;
+            let tab = &self.tabs[self.active_tab];
+            let styles: Vec<String> = tab.scene.document.objects.values()
+                .filter_map(|o| if let ObjectType::MLineStyle(s) = o { Some(s.name.clone()) } else { None })
+                .collect();
+            let selected_style = tab.scene.document.objects.values()
+                .find_map(|o| if let ObjectType::MLineStyle(s) = o {
+                    if s.name == self.mlstyle_selected { Some(s) } else { None }
+                } else { None });
+            mlstyle_overlay(styles, &self.mlstyle_selected, selected_style, tab.scene.document.header.multiline_style.clone())
+        } else {
+            iced::widget::Space::new().width(0).height(0).into()
+        };
+
         let dimstyle_layer: Element<'_, Message> = if self.dimstyle_open {
             let tab = &self.tabs[self.active_tab];
             let styles: Vec<String> = tab.scene.document.dim_styles
@@ -241,7 +256,7 @@ impl H7CAD {
             iced::widget::Space::new().width(0).height(0).into()
         };
 
-        stack![main_ui, self.app_menu.view(), snap_layer, dropdown_layer, layout_ctx_layer, page_setup_layer, dimstyle_layer].into()
+        stack![main_ui, self.app_menu.view(), snap_layer, dropdown_layer, layout_ctx_layer, page_setup_layer, mlstyle_layer, dimstyle_layer].into()
     }
 
     pub fn subscription(&self) -> Subscription<Message> {
@@ -1021,3 +1036,165 @@ fn dimstyle_overlay<'a>(
 
     stack![catcher, positioned].into()
 }
+
+// ── MLineStyle Dialog overlay ───────────────────────────────────────────────
+
+fn mlstyle_overlay<'a>(
+    styles: Vec<String>,
+    selected: &'a str,
+    selected_style: Option<&'a acadrust::objects::MLineStyle>,
+    current_style: String,
+) -> Element<'a, Message> {
+    use iced::Length::Shrink;
+
+    const PANEL_BG:  Color = Color { r: 0.15, g: 0.15, b: 0.15, a: 1.0 };
+    const BORDER:    Color = Color { r: 0.35, g: 0.35, b: 0.35, a: 1.0 };
+    const TEXT_COL:  Color = Color { r: 0.88, g: 0.88, b: 0.88, a: 1.0 };
+    const DIM_COL:   Color = Color { r: 0.55, g: 0.55, b: 0.55, a: 1.0 };
+    const ACCENT:    Color = Color { r: 0.25, g: 0.50, b: 0.85, a: 1.0 };
+    const ACTIVE_BG: Color = Color { r: 0.20, g: 0.40, b: 0.70, a: 1.0 };
+
+    let btn_style = |accent: bool| move |_: &Theme, status: button::Status| button::Style {
+        background: Some(Background::Color(match (accent, status) {
+            (true, button::Status::Hovered | button::Status::Pressed) =>
+                Color { r: 0.20, g: 0.42, b: 0.72, a: 1.0 },
+            (false, button::Status::Hovered | button::Status::Pressed) =>
+                Color { r: 0.28, g: 0.28, b: 0.28, a: 1.0 },
+            (true, _) => ACCENT,
+            _ => Color { r: 0.22, g: 0.22, b: 0.22, a: 1.0 },
+        })),
+        text_color: TEXT_COL,
+        border: Border { color: BORDER, width: 1.0, radius: 4.0.into() },
+        ..Default::default()
+    };
+
+    // Style list.
+    let style_items: Vec<Element<'_, Message>> = styles.iter().map(|name| {
+        let is_sel = name.as_str() == selected;
+        let is_cur = *name == current_style;
+        let label = if is_cur {
+            format!("{} ◀", name)
+        } else {
+            name.clone()
+        };
+        button(text(label).size(11).color(TEXT_COL))
+            .on_press(Message::MlStyleDialogSelect(name.clone()))
+            .style(move |_: &Theme, st| button::Style {
+                background: Some(Background::Color(match (is_sel, st) {
+                    (true, _) => ACTIVE_BG,
+                    (false, button::Status::Hovered | button::Status::Pressed) =>
+                        Color { r: 0.26, g: 0.26, b: 0.26, a: 1.0 },
+                    _ => Color::TRANSPARENT,
+                })),
+                text_color: TEXT_COL,
+                ..Default::default()
+            })
+            .padding([3, 8])
+            .width(Fill)
+            .into()
+    }).collect();
+
+    let style_panel = container(
+        column(style_items).spacing(2)
+    )
+    .style(|_: &Theme| container::Style {
+        background: Some(Background::Color(Color { r: 0.12, g: 0.12, b: 0.12, a: 1.0 })),
+        border: Border { color: BORDER, width: 1.0, radius: 4.0.into() },
+        ..Default::default()
+    })
+    .padding(4)
+    .width(160)
+    .height(240);
+
+    // Right panel: details for selected style.
+    let details: Element<'_, Message> = if let Some(s) = selected_style {
+        let info_row = |label: &'static str, val: String| -> Element<'_, Message> {
+            row![
+                text(label).size(11).color(DIM_COL).width(110),
+                text(val).size(11).color(TEXT_COL),
+            ].spacing(8).align_y(iced::Center).into()
+        };
+        let elem_rows: Vec<Element<'_, Message>> = s.elements.iter().enumerate().map(|(idx, e)| {
+            let color_str: String = match &e.color {
+                acadrust::types::Color::ByLayer => "ByLayer".into(),
+                acadrust::types::Color::ByBlock => "ByBlock".into(),
+                acadrust::types::Color::Index(i) => format!("ACI {}", i),
+                acadrust::types::Color::Rgb { r, g, b } => format!("#{:02X}{:02X}{:02X}", r, g, b),
+            };
+            let lt = if e.linetype.is_empty() { "ByLayer" } else { e.linetype.as_str() };
+            row![
+                text(format!("  {}:", idx)).size(10).color(DIM_COL).width(20),
+                text(format!("{:+.3}", e.offset)).size(10).color(TEXT_COL).width(60),
+                text(color_str).size(10).color(TEXT_COL).width(80),
+                text(lt).size(10).color(TEXT_COL),
+            ].spacing(4).align_y(iced::Center).into()
+        }).collect();
+
+        let mut col_items: Vec<Element<'_, Message>> = vec![
+            info_row("Name:", s.name.clone()),
+            info_row("Elements:", s.elements.len().to_string()),
+            text("  Off   Color        Ltype").size(10).color(DIM_COL).into(),
+        ];
+        col_items.extend(elem_rows);
+        column(col_items).spacing(6).into()
+    } else {
+        text("No style selected.").size(11).color(DIM_COL).into()
+    };
+
+    let right_panel = column![
+        details,
+        Space::new().height(Fill),
+        row![
+            button(text("Set Current").size(11))
+                .on_press(Message::MlStyleDialogSetCurrent)
+                .style(btn_style(true))
+                .padding([5, 10]),
+            button(text("New").size(11))
+                .on_press(Message::MlStyleDialogNew)
+                .style(btn_style(false))
+                .padding([5, 10]),
+            button(text("Delete").size(11))
+                .on_press(Message::MlStyleDialogDelete)
+                .style(btn_style(false))
+                .padding([5, 10]),
+        ].spacing(6),
+    ]
+    .spacing(10)
+    .width(280)
+    .height(240);
+
+    let panel = container(
+        column![
+            row![
+                text("Multiline Style Manager").size(13).color(TEXT_COL),
+                Space::new().width(Fill),
+                button(text("✕").size(12).color(DIM_COL))
+                    .on_press(Message::MlStyleDialogClose)
+                    .style(|_: &Theme, _| button::Style {
+                        background: Some(Background::Color(Color::TRANSPARENT)),
+                        text_color: DIM_COL,
+                        ..Default::default()
+                    })
+                    .padding([2, 6]),
+            ].align_y(iced::Center),
+            row![style_panel, right_panel].spacing(12).align_y(iced::Top),
+        ].spacing(10).padding(16)
+    )
+    .style(|_: &Theme| container::Style {
+        background: Some(Background::Color(PANEL_BG)),
+        border: Border { color: BORDER, width: 1.0, radius: 6.0.into() },
+        ..Default::default()
+    })
+    .width(Shrink);
+
+    let catcher = mouse_area(
+        container(iced::widget::Space::new().width(Fill).height(Fill))
+    ).on_press(Message::MlStyleDialogClose);
+
+    let positioned = container(panel)
+        .width(Fill).height(Fill)
+        .align_x(iced::Alignment::Center)
+        .align_y(iced::Alignment::Center);
+
+    stack![catcher, positioned].into()
+}

src/modules/home/draw/mline.rs

@@ -17,11 +17,17 @@ pub struct MlineCommand {
     points: Vec<Vec3>,
     scale: f64,
     waiting_scale: bool,
+    style_name: String,
 }
 
 impl MlineCommand {
+    #[allow(dead_code)]
     pub fn new() -> Self {
-        Self { points: vec![], scale: 1.0, waiting_scale: false }
+        Self { points: vec![], scale: 1.0, waiting_scale: false, style_name: "Standard".into() }
+    }
+
+    pub fn with_style(style_name: impl Into<String>) -> Self {
+        Self { points: vec![], scale: 1.0, waiting_scale: false, style_name: style_name.into() }
     }
 }
 
@@ -55,7 +61,7 @@ impl CadCommand for MlineCommand {
 
         // Close command
         if (up == "C" || up == "CLOSE") && self.points.len() >= 3 {
-            let entity = build_mline(&self.points, self.scale, true);
+            let entity = build_mline(&self.points, self.scale, true, &self.style_name);
             return Some(CmdResult::CommitAndExit(entity));
         }
 
@@ -85,7 +91,7 @@ impl CadCommand for MlineCommand {
         if self.points.len() < 2 {
             return CmdResult::Cancel;
         }
-        let entity = build_mline(&self.points, self.scale, false);
+        let entity = build_mline(&self.points, self.scale, false, &self.style_name);
         CmdResult::CommitAndExit(entity)
     }
 
@@ -104,12 +110,13 @@ impl CadCommand for MlineCommand {
             line_weight_px: 1.0,
             snap_pts: vec![],
             tangent_geoms: vec![],
+            aci: 0,
             key_vertices: vec![],
         })
     }
 }
 
-fn build_mline(pts: &[Vec3], scale: f64, closed: bool) -> EntityType {
+fn build_mline(pts: &[Vec3], scale: f64, closed: bool, style_name: &str) -> EntityType {
     let verts: Vec<Vector3> = pts.iter()
         .map(|p| Vector3::new(p.x as f64, p.z as f64, p.y as f64))
         .collect();
@@ -119,5 +126,6 @@ fn build_mline(pts: &[Vec3], scale: f64, closed: bool) -> EntityType {
         MLine::from_points(&verts)
     };
     mline.scale_factor = scale;
+    mline.style_name = style_name.to_string();
     EntityType::MLine(mline)
 }