Add Path tool support for G/R/S rotation and scaling with a single selected handle (#2180)

* grab_scale_path and backspace for pen

* minor improvements and fixes

* code-review changes

* Avoid more nesting, and other code cleanup

---------

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

editor/src/messages/input_mapper/input_mappings.rs

@@ -258,6 +258,8 @@ pub fn input_mappings() -> Mapping {
 		entry!(KeyDown(MouseRight); action_dispatch=PenToolMessage::Confirm),
 		entry!(KeyDown(Escape); action_dispatch=PenToolMessage::Confirm),
 		entry!(KeyDown(Enter); action_dispatch=PenToolMessage::Confirm),
+		entry!(KeyDown(Delete); action_dispatch=PenToolMessage::RemovePreviousHandle),
+		entry!(KeyDown(Backspace); action_dispatch=PenToolMessage::RemovePreviousHandle),
 		//
 		// FreehandToolMessage
 		entry!(PointerMove; action_dispatch=FreehandToolMessage::PointerMove),

editor/src/messages/tool/tool_message_handler.rs

@@ -76,8 +76,8 @@ impl MessageHandler<ToolMessage, ToolMessageData<'_>> for ToolMessageHandler {
 				self.tool_is_active = true;
 
 				// Send the old and new tools a transition to their FSM Abort states
-				let mut send_abort_to_tool = |tool_type, update_hints_and_cursor: bool| {
+				let mut send_abort_to_tool = |old_tool: ToolType, new_tool: ToolType, update_hints_and_cursor: bool| {
-					if let Some(tool) = tool_data.tools.get_mut(&tool_type) {
+					if let Some(tool) = tool_data.tools.get_mut(&new_tool) {
 						let mut data = ToolActionHandlerData {
 							document,
 							document_id,
@@ -101,9 +101,14 @@ impl MessageHandler<ToolMessage, ToolMessageData<'_>> for ToolMessageHandler {
 							tool.process_message(ToolMessage::UpdateCursor, responses, &mut data);
 						}
 					}
+
+					if matches!(old_tool, ToolType::Path | ToolType::Select) {
+						responses.add(TransformLayerMessage::CancelTransformOperation);
+					}
 				};
-				send_abort_to_tool(tool_type, true);
+
-				send_abort_to_tool(old_tool, false);
+				send_abort_to_tool(old_tool, tool_type, true);
+				send_abort_to_tool(old_tool, old_tool, false);
 
 				// Unsubscribe old tool from the broadcaster
 				tool_data.tools.get(&tool_type).unwrap().deactivate(responses);

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

@@ -648,19 +648,7 @@ impl Fsm for PathToolFsmState {
 				self
 			}
 			(Self::InsertPoint, PathToolMessage::Escape | PathToolMessage::Delete | PathToolMessage::RightClick) => tool_data.end_insertion(shape_editor, responses, InsertEndKind::Abort),
-			(Self::InsertPoint, PathToolMessage::GRS { key: propagate }) => {
+			(Self::InsertPoint, PathToolMessage::GRS { key: _ }) => PathToolFsmState::InsertPoint,
-				// MAYBE: use `InputMapperMessage::KeyDown(..)` instead
-				match propagate {
-					// TODO: Don't use `Key::G` directly, instead take it as a variable from the input mappings list like in all other places
-					Key::KeyG => responses.add(TransformLayerMessage::BeginGrab),
-					// TODO: Don't use `Key::R` directly, instead take it as a variable from the input mappings list like in all other places
-					Key::KeyR => responses.add(TransformLayerMessage::BeginRotate),
-					// TODO: Don't use `Key::S` directly, instead take it as a variable from the input mappings list like in all other places
-					Key::KeyS => responses.add(TransformLayerMessage::BeginScale),
-					_ => warn!("Unexpected GRS key"),
-				}
-				tool_data.end_insertion(shape_editor, responses, InsertEndKind::Abort)
-			}
 			// Mouse down
 			(
 				_,

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

@@ -62,6 +62,7 @@ pub enum PenToolMessage {
 	Undo,
 	UpdateOptions(PenOptionsUpdate),
 	RecalculateLatestPointsPosition,
+	RemovePreviousHandle,
 }
 
 #[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
@@ -175,6 +176,7 @@ impl<'a> MessageHandler<ToolMessage, &mut ToolActionHandlerData<'a>> for PenTool
 				PointerMove,
 				Confirm,
 				Abort,
+				RemovePreviousHandle,
 			),
 		}
 	}
@@ -685,6 +687,15 @@ impl Fsm for PenToolFsmState {
 					PenToolFsmState::PlacingAnchor
 				}
 			}
+			(PenToolFsmState::PlacingAnchor, PenToolMessage::RemovePreviousHandle) => {
+				if let Some(last_point) = tool_data.latest_points.last_mut() {
+					last_point.handle_start = last_point.pos;
+					responses.add(OverlaysMessage::Draw);
+				} else {
+					log::warn!("No latest point available to modify handle_start.");
+				}
+				self
+			}
 			(PenToolFsmState::DraggingHandle, PenToolMessage::DragStop) => tool_data
 				.finish_placing_handle(SnapData::new(document, input), transform, responses)
 				.unwrap_or(PenToolFsmState::PlacingAnchor),

editor/src/messages/tool/transform_layer/transform_layer_message_handler.rs

@@ -43,6 +43,7 @@ type TransformData<'a> = (&'a DocumentMessageHandler, &'a InputPreprocessorMessa
 impl MessageHandler<TransformLayerMessage, TransformData<'_>> for TransformLayerMessageHandler {
 	fn process_message(&mut self, message: TransformLayerMessage, responses: &mut VecDeque<Message>, (document, input, tool_data, shape_editor): TransformData) {
 		let using_path_tool = tool_data.active_tool_type == ToolType::Path;
+		let using_select_tool = tool_data.active_tool_type == ToolType::Select;
 
 		// TODO: Add support for transforming layer not in the document network
 		let selected_layers = document
@@ -75,10 +76,18 @@ impl MessageHandler<TransformLayerMessage, TransformData<'_>> for TransformLayer
 					let viewspace = document.metadata().transform_to_viewport(selected_layers[0]);
 
 					let mut point_count: usize = 0;
-					let get_location = |point: &ManipulatorPointId| point.get_position(&vector_data).map(|position| viewspace.transform_point2(position));
+					let get_location = |point: &&ManipulatorPointId| point.get_position(&vector_data).map(|position| viewspace.transform_point2(position));
 					let points = shape_editor.selected_points();
+					let selected_points: Vec<&ManipulatorPointId> = points.collect();
 
-					*selected.pivot = points.filter_map(get_location).inspect(|_| point_count += 1).sum::<DVec2>() / point_count as f64;
+					if let [point] = selected_points.as_slice() {
+						if let ManipulatorPointId::PrimaryHandle(_) | ManipulatorPointId::EndHandle(_) = point {
+							let anchor_position = point.get_anchor_position(&vector_data).unwrap();
+							*selected.pivot = viewspace.transform_point2(anchor_position);
+						} else {
+							*selected.pivot = selected_points.iter().filter_map(get_location).inspect(|_| point_count += 1).sum::<DVec2>() / point_count as f64;
+						}
+					}
 				}
 			} else {
 				*selected.pivot = selected.mean_average_of_pivots();
@@ -104,12 +113,13 @@ impl MessageHandler<TransformLayerMessage, TransformData<'_>> for TransformLayer
 				responses.add(NodeGraphMessage::RunDocumentGraph);
 			}
 			TransformLayerMessage::BeginGrab => {
-				if let TransformOperation::Grabbing(_) = self.transform_operation {
+				if (!using_path_tool && !using_select_tool)
-					return;
+					|| (using_path_tool && shape_editor.selected_points().next().is_none())
-				}
+					|| selected_layers.is_empty()
+					|| matches!(self.transform_operation, TransformOperation::Grabbing(_))
+				{
+					selected.original_transforms.clear();
 
-				// Don't allow grab with no selected layers
-				if selected_layers.is_empty() {
 					return;
 				}
 
@@ -120,13 +130,42 @@ impl MessageHandler<TransformLayerMessage, TransformData<'_>> for TransformLayer
 				selected.original_transforms.clear();
 			}
 			TransformLayerMessage::BeginRotate => {
-				if let TransformOperation::Rotating(_) = self.transform_operation {
+				let selected_points: Vec<&ManipulatorPointId> = shape_editor.selected_points().collect();
+
+				if (!using_path_tool && !using_select_tool)
+					|| (using_path_tool && selected_points.is_empty())
+					|| selected_layers.is_empty()
+					|| matches!(self.transform_operation, TransformOperation::Rotating(_))
+				{
+					selected.original_transforms.clear();
 					return;
 				}
 
-				// Don't allow rotate with no selected layers
+				let Some(vector_data) = selected_layers.first().and_then(|&layer| document.network_interface.compute_modified_vector(layer)) else {
-				if selected_layers.is_empty() {
+					selected.original_transforms.clear();
 					return;
+				};
+
+				if let [point] = selected_points.as_slice() {
+					if matches!(point, ManipulatorPointId::Anchor(_)) {
+						if let Some([handle1, handle2]) = point.get_handle_pair(&vector_data) {
+							let handle1_length = handle1.length(&vector_data);
+							let handle2_length = handle2.length(&vector_data);
+
+							if (handle1_length == 0. && handle2_length == 0.) || (handle1_length == f64::MAX && handle2_length == f64::MAX) {
+								return;
+							}
+						}
+					} else {
+						// TODO: Fix handle snap to anchor issue, see <https://discord.com/channels/731730685944922173/1217752903209713715>
+
+						let handle_length = point.as_handle().map(|handle| handle.length(&vector_data));
+
+						if handle_length == Some(0.) {
+							selected.original_transforms.clear();
+							return;
+						}
+					}
 				}
 
 				begin_operation(self.transform_operation, &mut self.typing, &mut self.mouse_position, &mut self.start_mouse);
@@ -136,13 +175,41 @@ impl MessageHandler<TransformLayerMessage, TransformData<'_>> for TransformLayer
 				selected.original_transforms.clear();
 			}
 			TransformLayerMessage::BeginScale => {
-				if let TransformOperation::Scaling(_) = self.transform_operation {
+				let selected_points: Vec<&ManipulatorPointId> = shape_editor.selected_points().collect();
+
+				if (using_path_tool && selected_points.is_empty())
+					|| (!using_path_tool && !using_select_tool)
+					|| selected_layers.is_empty()
+					|| matches!(self.transform_operation, TransformOperation::Scaling(_))
+				{
+					selected.original_transforms.clear();
 					return;
 				}
 
-				// Don't allow scale with no selected layers
+				let Some(vector_data) = selected_layers.first().and_then(|&layer| document.network_interface.compute_modified_vector(layer)) else {
-				if selected_layers.is_empty() {
+					selected.original_transforms.clear();
 					return;
+				};
+
+				if let [point] = selected_points.as_slice() {
+					if matches!(point, ManipulatorPointId::Anchor(_)) {
+						if let Some([handle1, handle2]) = point.get_handle_pair(&vector_data) {
+							let handle1_length = handle1.length(&vector_data);
+							let handle2_length = handle2.length(&vector_data);
+
+							if (handle1_length == 0. && handle2_length == 0.) || (handle1_length == f64::MAX && handle2_length == f64::MAX) {
+								selected.original_transforms.clear();
+								return;
+							}
+						}
+					} else {
+						let handle_length = point.as_handle().map(|handle| handle.length(&vector_data));
+
+						if handle_length == Some(0.) {
+							selected.original_transforms.clear();
+							return;
+						}
+					}
 				}
 
 				begin_operation(self.transform_operation, &mut self.typing, &mut self.mouse_position, &mut self.start_mouse);
@@ -215,6 +282,7 @@ impl MessageHandler<TransformLayerMessage, TransformData<'_>> for TransformLayer
 						}
 					};
 				}
+
 				self.mouse_position = input.mouse.position;
 			}
 			TransformLayerMessage::SelectionChanged => {

node-graph/gcore/src/vector/vector_data.rs

@@ -306,6 +306,13 @@ impl ManipulatorPointId {
 		}
 	}
 
+	pub fn get_anchor_position(&self, vector_data: &VectorData) -> Option<DVec2> {
+		match self {
+			ManipulatorPointId::EndHandle(_) | ManipulatorPointId::PrimaryHandle(_) => self.get_anchor(vector_data).and_then(|id| vector_data.point_domain.position_from_id(id)),
+			_ => self.get_position(vector_data),
+		}
+	}
+
 	/// Attempt to get a pair of handles. For an anchor this is the first two handles connected. For a handle it is self and the first opposing handle.
 	#[must_use]
 	pub fn get_handle_pair(self, vector_data: &VectorData) -> Option<[HandleId; 2]> {
@@ -396,6 +403,13 @@ impl HandleId {
 		}
 	}
 
+	/// Calculate the magnitude of the handle from the anchor.
+	pub fn length(self, vector_data: &VectorData) -> f64 {
+		let anchor_position = self.to_manipulator_point().get_anchor_position(vector_data).unwrap();
+		let handle_position = self.to_manipulator_point().get_position(vector_data);
+		handle_position.map(|pos| (pos - anchor_position).length()).unwrap_or(f64::MAX)
+	}
+
 	/// Set the handle's position relative to the anchor which is the start anchor for the primary handle and end anchor for the end handle.
 	#[must_use]
 	pub fn set_relative_position(self, relative_position: DVec2) -> VectorModificationType {