Pick spline control vertices with the configured screen aperture

src/app/command_driver.rs

@@ -312,6 +312,33 @@ impl OpenCADStudio {
         true
     }
 
+    /// Refresh screen-space feature picking immediately before point dispatch.
+    pub(super) fn refresh_command_point_pick_context(&mut self, i: usize) {
+        if self.tabs[i].active_cmd.as_ref()
+            .is_some_and(|command| command.wants_point_pick_context())
+        {
+            let scene = &self.tabs[i].scene;
+            let size = scene.selection.borrow().vp_size;
+            let edit = scene.viewport_edit_frame(size);
+            let tile = edit.as_ref().map(|(_, rect)| *rect)
+                .unwrap_or_else(|| scene.active_model_tile_bounds(size.0, size.1));
+            let bounds = iced::Rectangle { x: 0.0, y: 0.0, width: tile.width, height: tile.height };
+            let context = if bounds.width > 0.0 && bounds.height > 0.0 {
+                let (view, eye) = if let Some((camera, _)) = edit {
+                    (camera.view_proj_rte(bounds), camera.eye())
+                } else {
+                    let camera = scene.camera.borrow();
+                    (camera.view_proj_rte(bounds), camera.eye())
+                };
+                Some(crate::command::PointPickContext { view, eye, bounds,
+                    aperture_px: crate::ui::overlay::pick_box_aperture_px(self.pick_box) })
+            } else { None };
+            if let Some(command) = self.tabs[i].active_cmd.as_mut() {
+                command.set_point_pick_context(context);
+            }
+        }
+    }
+
     /// Drive the active command's step machine with one [`StepInput`], then
     /// apply the result. This is the single entry point every input source
     /// (command line, headless, dynamic input, plugin API, viewport) funnels
@@ -414,6 +441,7 @@ impl OpenCADStudio {
                 command.inject_selection_entities(entities);
             }
         }
+        if matches!(&input, StepInput::Point(_)) { self.refresh_command_point_pick_context(i); }
         let ctrl = self.ctrl_down;
         let shift = self.shift_down;
         let result: Option<CmdResult> = {

src/app/update/viewport.rs

@@ -3887,6 +3887,7 @@ impl OpenCADStudio {
                 } else if self.tabs[i].active_cmd.as_ref()
                     .is_some_and(|command| command.entity_pick_accepts_points())
                 {
+                    self.refresh_command_point_pick_context(i);
                     self.tabs[i].active_cmd.as_mut().map(|command| command.on_point(pick_wcs))
                 } else if self.tabs[i]
                     .active_cmd
@@ -3963,6 +3964,7 @@ impl OpenCADStudio {
                 // (LINE tangent to two circles, which needs both). When
                 // it does, sync last_point to the command's resolved
                 // anchor since it replaced the picked coordinate.
+                self.refresh_command_point_pick_context(i);
                 let handled = self.tabs[i]
                     .active_cmd
                     .as_mut()

src/command.rs

@@ -1939,6 +1939,15 @@ impl InputKind {
     }
 }
 
+/// Current screen projection and configured aperture for point-feature picking.
+#[derive(Clone, Copy)]
+pub struct PointPickContext {
+    pub view: glam::Mat4,
+    pub eye: DVec3,
+    pub bounds: iced::Rectangle,
+    pub aperture_px: f32,
+}
+
 pub trait CadCommand: Send {
     /// Keep the layer already carried by entities committed by this command
     /// instead of replacing it with the current drawing layer.
@@ -2006,6 +2015,12 @@ pub trait CadCommand: Send {
     /// Called when the user left-clicks in the viewport (point pick).
     fn on_point(&mut self, pt: DVec3) -> CmdResult;
 
+    /// Opt in only while a point input selects an existing point feature.
+    fn wants_point_pick_context(&self) -> bool { false }
+
+    /// Refreshed for each point input so zoom and viewport changes are reflected.
+    fn set_point_pick_context(&mut self, _context: Option<PointPickContext>) {}
+
     /// Called when the user presses Enter (finalize / next option).
     fn on_enter(&mut self) -> CmdResult;
 

src/modules/draw/modify/splinedit.rs

@@ -47,11 +47,31 @@ pub struct SplineditCommand {
     spline: Option<acadrust::entities::Spline>,
     pending: Option<acadrust::entities::Spline>,
     history: Vec<(acadrust::Handle, acadrust::entities::Spline)>,
+    pick_context: Option<crate::command::PointPickContext>,
 }
 
 impl SplineditCommand {
     pub fn new() -> Self {
-        Self { step: Step::SelectSpline, handle: acadrust::Handle::NULL, spline: None, pending: None, history: Vec::new() }
+        Self { step: Step::SelectSpline, handle: acadrust::Handle::NULL, spline: None, pending: None, history: Vec::new(), pick_context: None }
+    }
+
+    fn picked_vertex(&self, point: DVec3) -> Option<usize> {
+        let context = self.pick_context?;
+        let project = |point: DVec3| {
+            let clip = context.view * (point - context.eye).as_vec3().extend(1.0);
+            if !clip.is_finite() || clip.w <= 0.0 { return None; }
+            let screen = crate::scene::pick::hit_test::world_to_screen(
+                point, context.view, context.eye, context.bounds);
+            (screen.x.is_finite() && screen.y.is_finite()
+                && screen.x >= 0.0 && screen.x <= context.bounds.width
+                && screen.y >= 0.0 && screen.y <= context.bounds.height).then_some(screen)
+        };
+        let cursor = project(point)?;
+        self.spline.as_ref()?.control_points.iter().enumerate().filter_map(|(index, vertex)| {
+            let screen = project(DVec3::new(vertex.x, vertex.y, vertex.z))?;
+            let distance = (screen.x - cursor.x).hypot(screen.y - cursor.y);
+            (distance.is_finite() && distance <= context.aperture_px).then_some((index, distance))
+        }).min_by(|a, b| a.1.total_cmp(&b.1)).map(|(index, _)| index)
     }
 
     fn replace(&mut self, spline: acadrust::entities::Spline) -> CmdResult {
@@ -194,25 +214,24 @@ impl CadCommand for SplineditCommand {
         }
         Some(CmdResult::NeedPoint)
     }
+    fn wants_point_pick_context(&self) -> bool {
+        matches!(self.step, Step::Delete | Step::SelectVertex { .. })
+    }
+    fn set_point_pick_context(&mut self, context: Option<crate::command::PointPickContext>) {
+        self.pick_context = context;
+    }
     fn on_point(&mut self, point: DVec3) -> CmdResult {
         if !point.is_finite() { return CmdResult::NeedPoint; }
         match self.step {
             Step::SelectVertex { weight, refine } => {
-                if let Some(index) = self.spline.as_ref().and_then(|spline| spline.control_points.iter().enumerate()
-                    .min_by(|(_, a), (_, b)| {
-                        let distance = |p: &Vector3| point.distance_squared(DVec3::new(p.x, p.y, p.z));
-                        distance(a).total_cmp(&distance(b))
-                    }).map(|(index, _)| index)) {
+                if let Some(index) = self.picked_vertex(point) {
                     self.step = if weight { Step::Weight { index } } else { Step::Move { index, refine } };
                 }
                 CmdResult::NeedPoint
             }
             Step::Delete => {
                 let Some(source) = self.spline.as_ref() else { return CmdResult::NeedPoint; };
-                let Some(index) = source.control_points.iter().enumerate().min_by(|(_, a), (_, b)| {
-                    let distance = |p: &Vector3| point.distance_squared(DVec3::new(p.x, p.y, p.z));
-                    distance(a).total_cmp(&distance(b))
-                }).map(|(index, _)| index) else { return CmdResult::NeedPoint; };
+                let Some(index) = self.picked_vertex(point) else { return CmdResult::NeedPoint; };
                 let controls = source.control_points.iter().map(|point| [point.x, point.y, point.z]).collect();
                 let weights = if source.weights.is_empty() { vec![1.0; source.control_points.len()] }
                     else { source.weights.clone() };