Add Path tool support for Alt-dragging an anchor to pull out a fresh equidistant handle pair (#2496)

* Added initial logic for dragging

* Alt drag stop makes opposite handle back to its position

* Implement new requested behaviour

* Fix sharp point bug

* Apply suggestions from code review

* Add hints

---------

Co-authored-by: Keavon Chambers <keavon@keavon.com>

Author: 4adex

editor/src/messages/input_mapper/input_mappings.rs

@@ -212,7 +212,7 @@ pub fn input_mappings() -> Mapping {
 		entry!(KeyDown(Delete); modifiers=[Shift], action_dispatch=PathToolMessage::BreakPath),
 		entry!(KeyDown(Backspace); modifiers=[Shift], action_dispatch=PathToolMessage::BreakPath),
 		entry!(KeyDownNoRepeat(Tab); action_dispatch=PathToolMessage::SwapSelectedHandles),
-		entry!(KeyDown(MouseLeft); action_dispatch=PathToolMessage::MouseDown { direct_insert_without_sliding: Control, extend_selection: Shift, lasso_select: Control }),
+		entry!(KeyDown(MouseLeft); action_dispatch=PathToolMessage::MouseDown { direct_insert_without_sliding: Control, extend_selection: Shift, lasso_select: Control, handle_drag_from_anchor: Alt }),
 		entry!(KeyDown(MouseRight); action_dispatch=PathToolMessage::RightClick),
 		entry!(KeyDown(Escape); action_dispatch=PathToolMessage::Escape),
 		entry!(KeyDown(KeyG); action_dispatch=PathToolMessage::GRS { key: KeyG }),

editor/src/messages/tool/common_functionality/shape_editor.rs

@@ -742,6 +742,7 @@ impl ShapeState {
 		delta: DVec2,
 		equidistant: bool,
 		in_viewport_space: bool,
+		was_alt_dragging: bool,
 		opposite_handle_position: Option<DVec2>,
 		responses: &mut VecDeque<Message>,
 	) {
@@ -810,9 +811,11 @@ impl ShapeState {
 					let length = opposing_handle.copied().unwrap_or_else(|| transform.transform_vector2(other_position - anchor_position).length());
 					direction.map_or(other_position - anchor_position, |direction| transform.inverse().transform_vector2(-direction * length))
 				};
-				let modification_type = other.set_relative_position(new_relative);
 
-				responses.add(GraphOperationMessage::Vector { layer, modification_type });
+				if !was_alt_dragging {
+					let modification_type = other.set_relative_position(new_relative);
+					responses.add(GraphOperationMessage::Vector { layer, modification_type });
+				}
 			}
 		}
 	}

editor/src/messages/tool/tool_messages/path_tool.rs

@@ -15,8 +15,8 @@ use crate::messages::tool::common_functionality::shape_editor::{
 };
 use crate::messages::tool::common_functionality::snapping::{SnapCache, SnapCandidatePoint, SnapConstraint, SnapData, SnapManager};
 use graphene_core::renderer::Quad;
-use graphene_core::vector::{ManipulatorPointId, PointId};
-use graphene_std::vector::{NoHashBuilder, SegmentId};
+use graphene_core::vector::{ManipulatorPointId, PointId, VectorModificationType};
+use graphene_std::vector::{HandleId, NoHashBuilder, SegmentId, VectorData};
 use std::vec;
 
 #[derive(Default)]
@@ -65,6 +65,7 @@ pub enum PathToolMessage {
 		direct_insert_without_sliding: Key,
 		extend_selection: Key,
 		lasso_select: Key,
+		handle_drag_from_anchor: Key,
 	},
 	NudgeSelectedPoints {
 		delta_x: f64,
@@ -375,6 +376,8 @@ struct PathToolData {
 	angle: f64,
 	opposite_handle_position: Option<DVec2>,
 	snapping_axis: Option<Axis>,
+	alt_clicked_on_anchor: bool,
+	alt_dragging_from_anchor: bool,
 }
 
 impl PathToolData {
@@ -489,6 +492,7 @@ impl PathToolData {
 		extend_selection: bool,
 		direct_insert_without_sliding: bool,
 		lasso_select: bool,
+		handle_drag_from_anchor: bool,
 	) -> PathToolFsmState {
 		self.double_click_handled = false;
 		self.opposing_handle_lengths = None;
@@ -516,6 +520,31 @@ impl PathToolData {
 					self.saved_points_before_handle_drag = old_selection;
 				}
 
+				if handle_drag_from_anchor {
+					if let Some((layer, point)) = shape_editor.find_nearest_point_indices(&document.network_interface, input.mouse.position, SELECTION_THRESHOLD) {
+						// Check that selected point is an anchor
+						if let (Some(point_id), Some(vector_data)) = (point.as_anchor(), document.network_interface.compute_modified_vector(layer)) {
+							let handles = vector_data.all_connected(point_id).collect::<Vec<_>>();
+							self.alt_clicked_on_anchor = true;
+							for handle in &handles {
+								let modification_type = handle.set_relative_position(DVec2::ZERO);
+								responses.add(GraphOperationMessage::Vector { layer, modification_type });
+								for &handles in &vector_data.colinear_manipulators {
+									if handles.contains(&handle) {
+										let modification_type = VectorModificationType::SetG1Continuous { handles, enabled: false };
+										responses.add(GraphOperationMessage::Vector { layer, modification_type });
+									}
+								}
+							}
+
+							let manipulator_point_id = handles[0].to_manipulator_point();
+							shape_editor.deselect_all_points();
+							shape_editor.select_points_by_manipulator_id(&vec![manipulator_point_id]);
+							responses.add(PathToolMessage::SelectedPointUpdated);
+						}
+					}
+				}
+
 				self.start_dragging_point(selected_points, input, document, shape_editor);
 				responses.add(OverlaysMessage::Draw);
 			}
@@ -744,7 +773,7 @@ impl PathToolData {
 		let drag_start = self.drag_start_pos;
 		let opposite_delta = drag_start - current_mouse;
 
-		shape_editor.move_selected_points(None, document, opposite_delta, false, true, None, responses);
+		shape_editor.move_selected_points(None, document, opposite_delta, false, true, false, None, responses);
 
 		// Calculate the projected delta and shift the points along that delta
 		let delta = current_mouse - drag_start;
@@ -756,7 +785,7 @@ impl PathToolData {
 			_ => DVec2::new(delta.x, 0.),
 		};
 
-		shape_editor.move_selected_points(None, document, projected_delta, false, true, None, responses);
+		shape_editor.move_selected_points(None, document, projected_delta, false, true, false, None, responses);
 	}
 
 	fn stop_snap_along_axis(&mut self, shape_editor: &mut ShapeState, document: &DocumentMessageHandler, input: &InputPreprocessorMessageHandler, responses: &mut VecDeque<Message>) {
@@ -772,16 +801,33 @@ impl PathToolData {
 			_ => DVec2::new(opposite_delta.x, 0.),
 		};
 
-		shape_editor.move_selected_points(None, document, opposite_projected_delta, false, true, None, responses);
+		shape_editor.move_selected_points(None, document, opposite_projected_delta, false, true, false, None, responses);
 
 		// Calculate what actually would have been the original delta for the point, and apply that
 		let delta = current_mouse - drag_start;
 
-		shape_editor.move_selected_points(None, document, delta, false, true, None, responses);
+		shape_editor.move_selected_points(None, document, delta, false, true, false, None, responses);
 
 		self.snapping_axis = None;
 	}
 
+	fn get_normalized_tangent(&mut self, point: PointId, segment: SegmentId, vector_data: &VectorData) -> Option<DVec2> {
+		let other_point = vector_data.other_point(segment, point)?;
+		let position = ManipulatorPointId::Anchor(point).get_position(vector_data)?;
+
+		let mut handles = vector_data.all_connected(other_point);
+		let other_handle = handles.find(|handle| handle.segment == segment)?;
+
+		let target_position = if other_handle.length(vector_data) == 0. {
+			ManipulatorPointId::Anchor(other_point).get_position(vector_data)?
+		} else {
+			other_handle.to_manipulator_point().get_position(vector_data)?
+		};
+
+		let tangent_vector = target_position - position;
+		tangent_vector.try_normalize()
+	}
+
 	#[allow(clippy::too_many_arguments)]
 	fn drag(
 		&mut self,
@@ -829,9 +875,51 @@ impl PathToolData {
 		let handle_lengths = if equidistant { None } else { self.opposing_handle_lengths.take() };
 		let opposite = if lock_angle { None } else { self.opposite_handle_position };
 		let unsnapped_delta = current_mouse - previous_mouse;
+		let mut was_alt_dragging = false;
 
 		if self.snapping_axis.is_none() {
-			shape_editor.move_selected_points(handle_lengths, document, snapped_delta, equidistant, true, opposite, responses);
+			if self.alt_clicked_on_anchor && !self.alt_dragging_from_anchor && self.drag_start_pos.distance(input.mouse.position) > DRAG_THRESHOLD {
+				// Checking which direction the dragging begins
+				self.alt_dragging_from_anchor = true;
+				let Some(layer) = document.network_interface.selected_nodes().selected_layers(document.metadata()).next() else {
+					return;
+				};
+				let Some(vector_data) = document.network_interface.compute_modified_vector(layer) else { return };
+				let Some(point_id) = shape_editor.selected_points().next().unwrap().get_anchor(&vector_data) else {
+					return;
+				};
+
+				if vector_data.connected_count(point_id) == 2 {
+					let connected_segments: Vec<HandleId> = vector_data.all_connected(point_id).collect();
+					let segment1 = connected_segments[0];
+					let Some(tangent1) = self.get_normalized_tangent(point_id, segment1.segment, &vector_data) else {
+						return;
+					};
+					let segment2 = connected_segments[1];
+					let Some(tangent2) = self.get_normalized_tangent(point_id, segment2.segment, &vector_data) else {
+						return;
+					};
+
+					let delta = input.mouse.position - self.drag_start_pos;
+					let handle = if delta.dot(tangent1) >= delta.dot(tangent2) {
+						segment1.to_manipulator_point()
+					} else {
+						segment2.to_manipulator_point()
+					};
+
+					// Now change the selection to this handle
+					shape_editor.deselect_all_points();
+					shape_editor.select_points_by_manipulator_id(&vec![handle]);
+					responses.add(PathToolMessage::SelectionChanged);
+				}
+			}
+
+			if self.alt_dragging_from_anchor && !equidistant && self.alt_clicked_on_anchor {
+				was_alt_dragging = true;
+				self.alt_dragging_from_anchor = false;
+				self.alt_clicked_on_anchor = false;
+			}
+			shape_editor.move_selected_points(handle_lengths, document, snapped_delta, equidistant, true, was_alt_dragging, opposite, responses);
 			self.previous_mouse_position += document_to_viewport.inverse().transform_vector2(snapped_delta);
 		} else {
 			let Some(axis) = self.snapping_axis else { return };
@@ -840,7 +928,7 @@ impl PathToolData {
 				Axis::Y => DVec2::new(0., unsnapped_delta.y),
 				_ => DVec2::new(unsnapped_delta.x, 0.),
 			};
-			shape_editor.move_selected_points(handle_lengths, document, projected_delta, equidistant, true, opposite, responses);
+			shape_editor.move_selected_points(handle_lengths, document, projected_delta, equidistant, true, false, opposite, responses);
 			self.previous_mouse_position += document_to_viewport.inverse().transform_vector2(unsnapped_delta);
 		}
 
@@ -1024,16 +1112,27 @@ impl Fsm for PathToolFsmState {
 					direct_insert_without_sliding,
 					extend_selection,
 					lasso_select,
+					handle_drag_from_anchor,
 				},
 			) => {
 				let extend_selection = input.keyboard.get(extend_selection as usize);
 				let lasso_select = input.keyboard.get(lasso_select as usize);
 				let direct_insert_without_sliding = input.keyboard.get(direct_insert_without_sliding as usize);
+				let handle_drag_from_anchor = input.keyboard.get(handle_drag_from_anchor as usize);
 
 				tool_data.selection_mode = None;
 				tool_data.lasso_polygon.clear();
 
-				tool_data.mouse_down(shape_editor, document, input, responses, extend_selection, direct_insert_without_sliding, lasso_select)
+				tool_data.mouse_down(
+					shape_editor,
+					document,
+					input,
+					responses,
+					extend_selection,
+					direct_insert_without_sliding,
+					lasso_select,
+					handle_drag_from_anchor,
+				)
 			}
 			(
 				PathToolFsmState::Drawing { selection_shape },
@@ -1295,6 +1394,9 @@ impl Fsm for PathToolFsmState {
 					tool_data.handle_drag_toggle = false;
 				}
 
+				tool_data.alt_dragging_from_anchor = false;
+				tool_data.alt_clicked_on_anchor = false;
+
 				if tool_data.select_anchor_toggled {
 					shape_editor.deselect_all_points();
 					shape_editor.select_points_by_manipulator_id(&tool_data.saved_points_before_anchor_select_toggle);
@@ -1385,6 +1487,7 @@ impl Fsm for PathToolFsmState {
 					(delta_x, delta_y).into(),
 					true,
 					false,
+					false,
 					tool_data.opposite_handle_position,
 					responses,
 				);
@@ -1446,7 +1549,11 @@ impl Fsm for PathToolFsmState {
 				HintGroup(vec![HintInfo::mouse(MouseMotion::LmbDrag, "Select Area"), HintInfo::keys([Key::Control], "Lasso").prepend_plus()]),
 				HintGroup(vec![HintInfo::mouse(MouseMotion::Lmb, "Insert Point on Segment")]),
 				// TODO: Only show if at least one anchor is selected, and dynamically show either "Smooth" or "Sharp" based on the current state
-				HintGroup(vec![HintInfo::mouse(MouseMotion::LmbDouble, "Make Anchor Smooth/Sharp")]),
+				HintGroup(vec![
+					HintInfo::mouse(MouseMotion::LmbDouble, "Convert Anchor Point"),
+					HintInfo::keys_and_mouse([Key::Alt], MouseMotion::Lmb, "To Sharp"),
+					HintInfo::keys_and_mouse([Key::Alt], MouseMotion::LmbDrag, "To Smooth"),
+				]),
 				// TODO: Only show the following hints if at least one point is selected
 				HintGroup(vec![HintInfo::mouse(MouseMotion::LmbDrag, "Drag Selected")]),
 				HintGroup(vec![HintInfo::multi_keys([[Key::KeyG], [Key::KeyR], [Key::KeyS]], "Grab/Rotate/Scale Selected")]),