Feat: DIST / ID / AREA inquiry commands

Add three classic CAD measurement commands:
- DIST (DI): two-point pick → distance, angle, delta XYZ
- ID: one-point pick → coordinates
- AREA: multi-point polygon pick (Enter to close) → area + perimeter

New CmdResult::Measurement(String) variant ends active command and
prints result to command line without modifying the document.

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

src/app/cmd_result.rs

@@ -364,6 +364,13 @@ impl H7CAD {
                 self.tabs[i].scene.zoom_to_window(p1, p2);
                 self.command_line.push_output("Zoom Window");
             }
+            CmdResult::Measurement(msg) => {
+                self.tabs[i].active_cmd = None;
+                self.tabs[i].snap_result = None;
+                self.tabs[i].scene.clear_preview_wire();
+                self.restore_pre_cmd_tangent();
+                self.command_line.push_output(&msg);
+            }
         }
         // Focus the command-line input while a command is active; blur it when the command ends.
         if self.tabs[i].active_cmd.is_some() {

src/app/commands.rs

@@ -970,6 +970,28 @@ impl H7CAD {
                 }
             }
 
+            // ── Inquiry ──────────────────────────────────────────────────────
+            "DIST"|"DI" => {
+                use crate::modules::home::inquiry::dist::DistCommand;
+                let cmd = DistCommand::new();
+                self.command_line.push_info(&cmd.prompt());
+                self.tabs[i].active_cmd = Some(Box::new(cmd));
+            }
+
+            "ID" => {
+                use crate::modules::home::inquiry::id::IdCommand;
+                let cmd = IdCommand::new();
+                self.command_line.push_info(&cmd.prompt());
+                self.tabs[i].active_cmd = Some(Box::new(cmd));
+            }
+
+            "AREA" => {
+                use crate::modules::home::inquiry::area::AreaCommand;
+                let cmd = AreaCommand::new();
+                self.command_line.push_info(&cmd.prompt());
+                self.tabs[i].active_cmd = Some(Box::new(cmd));
+            }
+
             "HELP"|"?" => {
                 self.command_line.push_output(
                     "Draw: LINE CIRCLE ARC PLINE RECT POLY POINT ELLIPSE SPLINE RAY XLINE HATCH  |  \
@@ -977,6 +999,7 @@ impl H7CAD {
                      Array: ARRAY ARRAYRECT ARRAYPOLAR ARRAYPATH  |  \
                      Text: TEXT MTEXT LEADER MLEADER  |  \
                      Dimension: DIMLINEAR DIMANGULAR DIMRADIUS  |  \
+                     Inquiry: DIST ID AREA LIST  |  \
                      View: ZOOM EXTENTS VIEW LIST/SAVE/RESTORE/DELETE  |  \
                      Layer: LAYER LIST/NEW/ON/OFF/FREEZE/THAW/LOCK/UNLOCK/COLOR/SET  |  \
                      Viewport: MVIEW VPLAYER VPORTS MS PS DRAWORDER  |  \

src/command/mod.rs

@@ -93,6 +93,8 @@ pub enum CmdResult {
     PasteClipboard { base_pt: Vec3 },
     /// Zoom the model-space camera to fit the given corner points; end command.
     ZoomToWindow { p1: Vec3, p2: Vec3 },
+    /// Print a measurement result to the command line and end the command.
+    Measurement(String),
 }
 
 // ── Trait ─────────────────────────────────────────────────────────────────

src/modules/home/inquiry/area.rs

@@ -0,0 +1,79 @@
+// AREA command — compute area and perimeter of a polygon picked point by point.
+// Press Enter to close and calculate.
+
+use glam::Vec3;
+
+use crate::command::{CadCommand, CmdResult};
+use crate::scene::wire_model::WireModel;
+
+pub struct AreaCommand {
+    points: Vec<Vec3>,
+}
+
+impl AreaCommand {
+    pub fn new() -> Self {
+        Self { points: vec![] }
+    }
+}
+
+impl CadCommand for AreaCommand {
+    fn name(&self) -> &'static str {
+        "AREA"
+    }
+
+    fn prompt(&self) -> String {
+        if self.points.is_empty() {
+            "AREA  Specify first corner point (Enter to cancel):".into()
+        } else {
+            format!(
+                "AREA  Specify next point ({} picked, Enter to calculate):",
+                self.points.len()
+            )
+        }
+    }
+
+    fn on_point(&mut self, pt: Vec3) -> CmdResult {
+        self.points.push(pt);
+        CmdResult::NeedPoint
+    }
+
+    fn on_enter(&mut self) -> CmdResult {
+        if self.points.len() < 3 {
+            return CmdResult::Cancel;
+        }
+        // Shoelace formula in the XZ plane (Y-up world)
+        let n = self.points.len();
+        let mut area_sum = 0.0f32;
+        let mut perimeter = 0.0f32;
+        for idx in 0..n {
+            let a = self.points[idx];
+            let b = self.points[(idx + 1) % n];
+            area_sum += a.x * b.z - b.x * a.z;
+            perimeter += (b - a).length();
+        }
+        let area = (area_sum * 0.5).abs();
+        let msg = format!("Area = {area:.4},  Perimeter = {perimeter:.4}");
+        CmdResult::Measurement(msg)
+    }
+
+    fn on_mouse_move(&mut self, pt: Vec3) -> Option<WireModel> {
+        if self.points.is_empty() {
+            return None;
+        }
+        let mut pts: Vec<[f32; 3]> = self.points.iter().map(|p| [p.x, p.y, p.z]).collect();
+        pts.push([pt.x, pt.y, pt.z]);
+        pts.push([self.points[0].x, self.points[0].y, self.points[0].z]);
+        Some(WireModel {
+            name: "area_preview".into(),
+            points: pts,
+            color: WireModel::CYAN,
+            selected: false,
+            pattern_length: 0.0,
+            pattern: [0.0; 8],
+            line_weight_px: 1.0,
+            snap_pts: vec![],
+            tangent_geoms: vec![],
+            key_vertices: vec![],
+        })
+    }
+}

src/modules/home/inquiry/dist.rs

@@ -0,0 +1,74 @@
+// DIST command — measure distance and angle between two picked points.
+
+use glam::Vec3;
+
+use crate::command::{CadCommand, CmdResult};
+use crate::scene::wire_model::WireModel;
+
+pub struct DistCommand {
+    first: Option<Vec3>,
+}
+
+impl DistCommand {
+    pub fn new() -> Self {
+        Self { first: None }
+    }
+}
+
+impl CadCommand for DistCommand {
+    fn name(&self) -> &'static str {
+        "DIST"
+    }
+
+    fn prompt(&self) -> String {
+        if self.first.is_none() {
+            "DIST  Specify first point:".into()
+        } else {
+            "DIST  Specify second point:".into()
+        }
+    }
+
+    fn on_point(&mut self, pt: Vec3) -> CmdResult {
+        if let Some(p1) = self.first {
+            let delta = pt - p1;
+            let dist = delta.length();
+            let dx = delta.x;
+            let dy = delta.z; // Y-up world: Z is the "drawing Y"
+            let dz = delta.y; // Y-up world: Y is elevation
+
+            // Angle in XY plane (XZ in world coords) — degrees from +X
+            let angle_xy = dy.atan2(dx).to_degrees();
+            // Angle from XY plane toward Z (elevation angle)
+            let dist_xy = dx.hypot(dy);
+            let angle_z = dz.atan2(dist_xy).to_degrees();
+
+            let msg = format!(
+                "Distance = {dist:.4},  Angle in XY Plane = {angle_xy:.4}°,  Angle from XY Plane = {angle_z:.4}°\n  Delta X = {dx:.4},  Delta Y = {dy:.4},  Delta Z = {dz:.4}",
+            );
+            CmdResult::Measurement(msg)
+        } else {
+            self.first = Some(pt);
+            CmdResult::NeedPoint
+        }
+    }
+
+    fn on_enter(&mut self) -> CmdResult {
+        CmdResult::Cancel
+    }
+
+    fn on_mouse_move(&mut self, pt: Vec3) -> Option<WireModel> {
+        let p1 = self.first?;
+        Some(WireModel {
+            name: "dist_preview".into(),
+            points: vec![[p1.x, p1.y, p1.z], [pt.x, pt.y, pt.z]],
+            color: WireModel::CYAN,
+            selected: false,
+            pattern_length: 0.0,
+            pattern: [0.0; 8],
+            line_weight_px: 1.0,
+            snap_pts: vec![],
+            tangent_geoms: vec![],
+            key_vertices: vec![],
+        })
+    }
+}

src/modules/home/inquiry/id.rs

@@ -0,0 +1,36 @@
+// ID command — report coordinates of a picked point.
+
+use glam::Vec3;
+
+use crate::command::{CadCommand, CmdResult};
+
+pub struct IdCommand;
+
+impl IdCommand {
+    pub fn new() -> Self {
+        Self
+    }
+}
+
+impl CadCommand for IdCommand {
+    fn name(&self) -> &'static str {
+        "ID"
+    }
+
+    fn prompt(&self) -> String {
+        "ID  Specify point:".into()
+    }
+
+    fn on_point(&mut self, pt: Vec3) -> CmdResult {
+        // Y-up world: X stays X, Z→drawing Y, Y→elevation Z
+        let x = pt.x;
+        let y = pt.z;
+        let z = pt.y;
+        let msg = format!("X = {x:.4},  Y = {y:.4},  Z = {z:.4}");
+        CmdResult::Measurement(msg)
+    }
+
+    fn on_enter(&mut self) -> CmdResult {
+        CmdResult::Cancel
+    }
+}

src/modules/home/inquiry/mod.rs

@@ -0,0 +1,3 @@
+pub mod area;
+pub mod dist;
+pub mod id;

src/modules/home/mod.rs

@@ -5,6 +5,7 @@ pub mod defaults;
 mod donate;
 pub mod draw;
 pub mod groups;
+pub mod inquiry;
 pub mod layers;
 pub mod modify;
 pub mod properties;