Fix point nudging to work in document space (#2095)

* Modified Path tool Behaviour

* Make the code simpler and more self-descriptive

* Make it work for transformed layers

---------

Co-authored-by: Keavon Chambers <[email protected]>

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

@@ -612,15 +612,24 @@ impl ShapeState {
 	}
 
 	/// Move the selected points by dragging the mouse.
-	pub fn move_selected_points(&self, handle_lengths: Option<OpposingHandleLengths>, document: &DocumentMessageHandler, delta: DVec2, equidistant: bool, responses: &mut VecDeque<Message>) {
+	pub fn move_selected_points(
+		&self,
+		handle_lengths: Option<OpposingHandleLengths>,
+		document: &DocumentMessageHandler,
+		delta: DVec2,
+		equidistant: bool,
+		responses: &mut VecDeque<Message>,
+		in_viewport_space: bool,
+	) {
 		for (&layer, state) in &self.selected_shape_state {
-			let Some(vector_data) = document.network_interface.compute_modified_vector(layer) else {
-				continue;
-			};
+			let Some(vector_data) = document.network_interface.compute_modified_vector(layer) else { continue };
+
 			let opposing_handles = handle_lengths.as_ref().and_then(|handle_lengths| handle_lengths.get(&layer));
 
-			let transform = document.metadata().transform_to_viewport(layer);
-			let delta = transform.inverse().transform_vector2(delta);
+			let transform_to_viewport_space = document.metadata().transform_to_viewport(layer);
+			let transform_to_document_space = document.metadata().transform_to_document(layer);
+			let delta_transform = if in_viewport_space { transform_to_viewport_space } else { transform_to_document_space };
+			let delta = delta_transform.inverse().transform_vector2(delta);
 
 			for &point in state.selected_points.iter() {
 				let handle = match point {
@@ -654,7 +663,8 @@ impl ShapeState {
 				let new_relative = if equidistant {
 					-(handle_position - anchor_position)
 				} else {
-					let transform = document.metadata().document_to_viewport.inverse() * transform;
+					// TODO: Is this equivalent to `transform_to_document_space`? If changed, the before and after should be tested.
+					let transform = document.metadata().document_to_viewport.inverse() * transform_to_viewport_space;
 					let Some(other_position) = other.to_manipulator_point().get_position(&vector_data) else {
 						continue;
 					};

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

@@ -472,7 +472,7 @@ impl PathToolData {
 		let previous_mouse = document.metadata().document_to_viewport.transform_point2(self.previous_mouse_position);
 		let snapped_delta = shape_editor.snap(&mut self.snap_manager, &self.snap_cache, document, input, previous_mouse);
 		let handle_lengths = if equidistant { None } else { self.opposing_handle_lengths.take() };
-		shape_editor.move_selected_points(handle_lengths, document, snapped_delta, equidistant, responses);
+		shape_editor.move_selected_points(handle_lengths, document, snapped_delta, equidistant, responses, true);
 		self.previous_mouse_position += document.metadata().document_to_viewport.inverse().transform_vector2(snapped_delta);
 	}
 }
@@ -786,7 +786,7 @@ impl Fsm for PathToolFsmState {
 			}
 			(_, PathToolMessage::PointerMove { .. }) => self,
 			(_, PathToolMessage::NudgeSelectedPoints { delta_x, delta_y }) => {
-				shape_editor.move_selected_points(tool_data.opposing_handle_lengths.take(), document, (delta_x, delta_y).into(), true, responses);
+				shape_editor.move_selected_points(tool_data.opposing_handle_lengths.take(), document, (delta_x, delta_y).into(), true, responses, false);
 
 				PathToolFsmState::Ready
 			}