Fixes the Path tool snapping to the X or Y axis with Shift held for handles (#2969)

Author: Thunder-Blaze

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

@@ -1149,8 +1149,6 @@ impl PathToolData {
 		let drag_start = self.drag_start_pos;
 		let opposite_delta = drag_start - current_mouse;
 
-		shape_editor.move_selected_points_and_segments(None, document, opposite_delta, false, true, false, None, false, responses);
-
 		// Calculate the projected delta and shift the points along that delta
 		let delta = current_mouse - drag_start;
 		let axis = if delta.x.abs() >= delta.y.abs() { Axis::X } else { Axis::Y };
@@ -1161,7 +1159,8 @@ impl PathToolData {
 			_ => DVec2::new(delta.x, 0.),
 		};
 
-		shape_editor.move_selected_points_and_segments(None, document, projected_delta, false, true, false, None, false, responses);
+		// Apply the two deltas combined
+		shape_editor.move_selected_points_and_segments(None, document, opposite_delta + projected_delta, false, true, false, None, false, responses);
 	}
 
 	fn stop_snap_along_axis(&mut self, shape_editor: &mut ShapeState, document: &DocumentMessageHandler, input: &InputPreprocessorMessageHandler, responses: &mut VecDeque<Message>) {
@@ -1177,12 +1176,11 @@ impl PathToolData {
 			_ => DVec2::new(opposite_delta.x, 0.),
 		};
 
-		shape_editor.move_selected_points_and_segments(None, document, opposite_projected_delta, false, true, false, None, false, 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_and_segments(None, document, delta, false, true, false, None, false, responses);
+		// Apply the two deltas combined
+		shape_editor.move_selected_points_and_segments(None, document, opposite_projected_delta + delta, false, true, false, None, false, responses);
 
 		self.snapping_axis = None;
 	}
@@ -1509,24 +1507,50 @@ impl PathToolData {
 			self.previous_mouse_position += document_to_viewport.inverse().transform_vector2(snapped_delta);
 		} else {
 			let Some(axis) = self.snapping_axis else { return };
-			let projected_delta = match axis {
-				Axis::X => DVec2::new(unsnapped_delta.x, 0.),
-				Axis::Y => DVec2::new(0., unsnapped_delta.y),
-				_ => DVec2::new(unsnapped_delta.x, 0.),
-			};
-			shape_editor.move_selected_points_and_segments(handle_lengths, document, projected_delta, equidistant, true, false, opposite, false, responses);
-			self.previous_mouse_position += document_to_viewport.inverse().transform_vector2(unsnapped_delta);
-		}
 
-		// Constantly checking and changing the snapping axis based on current mouse position
-		if snap_axis && self.snapping_axis.is_some() {
-			let Some(current_axis) = self.snapping_axis else { return };
+			// Constantly checking and changing the snapping axis based on current mouse position
 			let total_delta = self.drag_start_pos - input.mouse.position;
+			let mut current_axis = axis;
+			if (total_delta.x.abs() > total_delta.y.abs() && axis == Axis::Y) || (total_delta.y.abs() > total_delta.x.abs() && axis == Axis::X) {
+				current_axis = if axis == Axis::X { Axis::Y } else { Axis::X };
+			}
+
+			let document_to_viewport = document.metadata().document_to_viewport;
 
-			if (total_delta.x.abs() > total_delta.y.abs() && current_axis == Axis::Y) || (total_delta.y.abs() > total_delta.x.abs() && current_axis == Axis::X) {
-				self.stop_snap_along_axis(shape_editor, document, input, responses);
-				self.start_snap_along_axis(shape_editor, document, input, responses);
+			// Correct the position from the old axis projection to the new one
+			if current_axis != axis {
+				let previous_delta = previous_mouse - self.drag_start_pos;
+				let current_delta = current_mouse - self.drag_start_pos;
+
+				// Where the shape currently IS
+				let previous_projected = match axis {
+					Axis::X => DVec2::new(previous_delta.x, 0.),
+					Axis::Y => DVec2::new(0., previous_delta.y),
+					_ => DVec2::new(previous_delta.x, 0.),
+				};
+
+				// Where we want to GO
+				let current_projected = match current_axis {
+					Axis::X => DVec2::new(current_delta.x, 0.),
+					Axis::Y => DVec2::new(0., current_delta.y),
+					_ => DVec2::new(current_delta.x, 0.),
+				};
+
+				let snap_delta = current_projected - previous_projected;
+				shape_editor.move_selected_points_and_segments(handle_lengths, document, snap_delta, equidistant, true, false, opposite, false, responses);
+
+				self.snapping_axis = Some(current_axis);
+			} else {
+				// Standard incremental move along the same axis
+				let projected_delta = match axis {
+					Axis::X => DVec2::new(unsnapped_delta.x, 0.),
+					Axis::Y => DVec2::new(0., unsnapped_delta.y),
+					_ => DVec2::new(unsnapped_delta.x, 0.),
+				};
+				shape_editor.move_selected_points_and_segments(handle_lengths, document, projected_delta, equidistant, true, false, opposite, false, responses);
 			}
+
+			self.previous_mouse_position += document_to_viewport.inverse().transform_vector2(unsnapped_delta);
 		}
 	}