Complete automatic constraint behavior

src/scene/parametric_solve.rs

@@ -1549,6 +1549,44 @@ type SolveResult = (
     )>,
 );
 
+fn retained_line_length(entity: &EntityType, segment: Option<usize>) -> Option<f64> {
+    match (entity, segment) {
+        (EntityType::Line(line), None) => Some((line.end - line.start).length()),
+        (EntityType::LwPolyline(polyline), Some(index)) => {
+            let world = crate::entities::curve::lwpolyline_world_xy(polyline)?;
+            let a = world.vertices.get(index)?.location;
+            let b = if let Some(vertex) = world.vertices.get(index + 1) {
+                vertex.location
+            } else if world.is_closed {
+                world.vertices.first()?.location
+            } else {
+                return None;
+            };
+            Some((b - a).length())
+        }
+        (EntityType::Polyline2D(polyline), Some(index)) => {
+            let a = polyline.vertices.get(index)?.location;
+            let b = if let Some(vertex) = polyline.vertices.get(index + 1) {
+                vertex.location
+            } else if polyline.is_closed() {
+                polyline.vertices.first()?.location
+            } else {
+                return None;
+            };
+            Some((b - a).length())
+        }
+        _ => None,
+    }
+}
+
+fn retained_radius(entity: &EntityType) -> Option<f64> {
+    match entity {
+        EntityType::Circle(circle) => Some(circle.radius),
+        EntityType::Arc(arc) => Some(arc.radius),
+        _ => None,
+    }
+}
+
 /// Rebuilds `set`'s entire `cadkernel_constraints::System` from current document
 /// geometry, solves it, and returns the resulting entity states for every
 /// handle whose registered coordinates actually moved beyond floating-point
@@ -1564,6 +1602,9 @@ fn solve_scope(
     document: &acadrust::CadDocument,
     drawing_params: &ParameterTable,
     set: &ParametricConstraintSet,
+    driven_refs: &[ParametricRef],
+    retain_size: bool,
+    retained_before: &HashMap<Handle, std::sync::Arc<EntityType>>,
 ) -> Option<SolveResult> {
     let params = if set.local_parameters.is_empty() {
         drawing_params
@@ -1597,6 +1638,81 @@ fn solve_scope(
         return None;
     }
 
+    // Preserve current line lengths and radii for this solve when
+    // CONSTRAINTSOLVEMODE requests it. These temporary equations guide the
+    // solution without becoming persistent dimensional constraints.
+    if retain_size {
+        for (handle, geom) in &cache {
+            match geom {
+                EntityGeom::Line(line) => {
+                    let current_length = {
+                        let store = sys.store();
+                        let dx = store.get(line.p2.x) - store.get(line.p1.x);
+                        let dy = store.get(line.p2.y) - store.get(line.p1.y);
+                        (dx * dx + dy * dy).sqrt()
+                    };
+                    let length = retained_before
+                        .get(handle)
+                        .and_then(|entity| retained_line_length(entity, None))
+                        .unwrap_or(current_length);
+                    let target = sys.add_param(length, true);
+                    sys.add_constraint(Rc::new(P2PDistance::new(line.p1, line.p2, target)));
+                }
+                EntityGeom::Polyline {
+                    points,
+                    straight,
+                    closed,
+                } => {
+                    for index in 0..straight.len() {
+                        if !straight[index] {
+                            continue;
+                        }
+                        let Some(a) = points.get(index).copied() else {
+                            continue;
+                        };
+                        let b = if let Some(point) = points.get(index + 1).copied() {
+                            Some(point)
+                        } else if *closed {
+                            points.first().copied()
+                        } else {
+                            None
+                        };
+                        let Some(b) = b else { continue };
+                        let current_length = {
+                            let store = sys.store();
+                            let dx = store.get(b.x) - store.get(a.x);
+                            let dy = store.get(b.y) - store.get(a.y);
+                            (dx * dx + dy * dy).sqrt()
+                        };
+                        let length = retained_before
+                            .get(handle)
+                            .and_then(|entity| retained_line_length(entity, Some(index)))
+                            .unwrap_or(current_length);
+                        let target = sys.add_param(length, true);
+                        sys.add_constraint(Rc::new(P2PDistance::new(a, b, target)));
+                    }
+                }
+                EntityGeom::Circle(circle) => {
+                    let radius = retained_before
+                        .get(handle)
+                        .and_then(|entity| retained_radius(entity))
+                        .unwrap_or_else(|| sys.store().get(circle.rad));
+                    let target = sys.add_param(radius, true);
+                    sys.add_constraint(Rc::new(Equal::new(circle.rad, target, 1.0)));
+                }
+                EntityGeom::Arc(arc) => {
+                    let radius = retained_before
+                        .get(handle)
+                        .and_then(|entity| retained_radius(entity))
+                        .unwrap_or_else(|| sys.store().get(arc.circle.rad));
+                    let target = sys.add_param(radius, true);
+                    sys.add_constraint(Rc::new(Equal::new(arc.circle.rad, target, 1.0)));
+                }
+                _ => {}
+            }
+        }
+    }
+
     // Arc rules (this module's doc comment): keep every registered arc's
     // `start`/`end` points consistent with its center/radius/angle,
     // unconditionally — the kernel adds these the moment an arc
@@ -1633,6 +1749,33 @@ fn solve_scope(
         )));
     }
 
+    // A point explicitly edited by a grip, STRETCH, or Properties is the
+    // driver's target for this solve. Pin its current coordinates for this
+    // solve only so constrained neighbours respond while the chosen point
+    // stays at the exact cursor or typed coordinate.
+    for reference in driven_refs {
+        if !set
+            .constraints
+            .iter()
+            .any(|constraint| constraint.refs.iter().any(|r| r.entity == reference.entity))
+        {
+            continue;
+        }
+        let Some(point) =
+            resolve_constraint_point(document, &mut sys, &mut cache, *reference)
+        else {
+            continue;
+        };
+        let (x, y) = {
+            let store = sys.store();
+            (store.get(point.x), store.get(point.y))
+        };
+        let target_x = sys.add_param(x, true);
+        let target_y = sys.add_param(y, true);
+        sys.add_constraint(Rc::new(Equal::new(point.x, target_x, 1.0)));
+        sys.add_constraint(Rc::new(Equal::new(point.y, target_y, 1.0)));
+    }
+
     // Ellipse rules (same motivation as arc rules, different mechanism):
     // `cadkernel_constraints::geo::Ellipse` stores `focus1` as an absolute point, not an
     // offset from `center`. If some constraint (e.g. Concentric) pulls only
@@ -2151,9 +2294,43 @@ impl Scene {
     /// the resulting `(Handle, ChangeKind::Modified)` entries the same way
     /// `refresh_associative_dimensions`/`_hatches` do, for `bump_entities`
     /// to fold into its own `changes` vec.
+    #[allow(dead_code)]
     pub(crate) fn refresh_parametric_constraints(
         &mut self,
         changes: &[(Handle, ChangeKind)],
+    ) -> Vec<(Handle, ChangeKind)> {
+        self.refresh_parametric_constraints_with_policy(changes, &[], false)
+    }
+
+    #[allow(dead_code)]
+    pub(crate) fn refresh_parametric_constraints_with_driven(
+        &mut self,
+        changes: &[(Handle, ChangeKind)],
+        driven_refs: &[ParametricRef],
+    ) -> Vec<(Handle, ChangeKind)> {
+        self.refresh_parametric_constraints_with_policy(changes, driven_refs, false)
+    }
+
+    pub(crate) fn refresh_parametric_constraints_with_policy(
+        &mut self,
+        changes: &[(Handle, ChangeKind)],
+        driven_refs: &[ParametricRef],
+        retain_size: bool,
+    ) -> Vec<(Handle, ChangeKind)> {
+        self.refresh_parametric_constraints_with_originals(
+            changes,
+            driven_refs,
+            retain_size,
+            &[],
+        )
+    }
+
+    pub(crate) fn refresh_parametric_constraints_with_originals(
+        &mut self,
+        changes: &[(Handle, ChangeKind)],
+        driven_refs: &[ParametricRef],
+        retain_size: bool,
+        retained_originals: &[(Handle, EntityType)],
     ) -> Vec<(Handle, ChangeKind)> {
         // An erased entity takes its constraints with it instead of leaving
         // dangling references. Done first,
@@ -2185,6 +2362,25 @@ impl Scene {
             }
         }
 
+        let retained_before: HashMap<Handle, std::sync::Arc<EntityType>> = if retain_size {
+            let mut retained: HashMap<Handle, std::sync::Arc<EntityType>> = self
+                .undo_recording
+                .as_ref()
+                .into_iter()
+                .flat_map(|recording| recording.before.iter())
+                .filter_map(|(handle, entity)| {
+                    entity
+                        .as_ref()
+                        .map(|entity| (*handle, std::sync::Arc::clone(entity)))
+                })
+                .collect();
+            for (handle, entity) in retained_originals {
+                retained.insert(*handle, std::sync::Arc::new(entity.clone()));
+            }
+            retained
+        } else {
+            HashMap::new()
+        };
         let mut result = Vec::new();
         for i in 0..self.parametric_constraints.len() {
             let touched = changes.iter().any(|(handle, _)| {
@@ -2200,6 +2396,9 @@ impl Scene {
                 &self.document,
                 &self.named_parameters,
                 &self.parametric_constraints[i],
+                driven_refs,
+                retain_size,
+                &retained_before,
             ) else {
                 continue;
             };
@@ -2224,10 +2423,17 @@ impl Scene {
     pub(crate) fn solve_parametric_constraints_preview(
         &self,
         touched: &[Handle],
+        driven_refs: &[ParametricRef],
+        retain_size: bool,
+        retained_originals: &[(Handle, EntityType)],
     ) -> Vec<(Handle, EntityType)> {
         if self.parametric_constraints.is_empty() || touched.is_empty() {
             return Vec::new();
         }
+        let retained_before: HashMap<Handle, std::sync::Arc<EntityType>> = retained_originals
+            .iter()
+            .map(|(handle, entity)| (*handle, std::sync::Arc::new(entity.clone())))
+            .collect();
         let mut result = Vec::new();
         for set in &self.parametric_constraints {
             let is_touched = touched
@@ -2236,8 +2442,14 @@ impl Scene {
             if !is_touched {
                 continue;
             }
-            let Some((solved, _dof, _conflicts)) =
-                solve_scope(&self.document, &self.named_parameters, set)
+            let Some((solved, _dof, _conflicts)) = solve_scope(
+                &self.document,
+                &self.named_parameters,
+                set,
+                driven_refs,
+                retain_size,
+                &retained_before,
+            )
             else {
                 continue;
             };
@@ -2515,7 +2727,7 @@ mod tests {
         }
         let b_before = scene.document.get_entity(b).cloned();
 
-        let solved = scene.solve_parametric_constraints_preview(&[a]);
+        let solved = scene.solve_parametric_constraints_preview(&[a], &[], false, &[]);
 
         assert_eq!(
             scene.document.get_entity(b),