Fix PTZ coordinate drift during drag operations

This shifts all dragging offset calculations in TransformLayer, SelectTool, and PathTool to document space, removing any dependency on cached viewport projections for state logic. Both BoundingBoxManager's interactions and custom Path selection behaviors now properly invalidate and lazily reload viewport layouts on CanvasTransformed updates, resolving issues with geometry moving opposite the viewport during pan/tilt/zoom.

Author: afrdbaig7

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

@@ -368,6 +368,52 @@ pub fn snap_drag(start: DVec2, current: DVec2, snap_to_axis: bool, axis: Axis, s
 	document.metadata().document_to_viewport.transform_vector2(offset)
 }
 
+/// Snaps a dragging event using document-space drag state so PTZ changes do not invalidate the drag anchor.
+pub fn snap_drag_from_document(start: DVec2, current: DVec2, snap_to_axis: bool, axis: Axis, snap_data: SnapData, snap_manager: &mut SnapManager, candidates: &[SnapCandidatePoint]) -> DVec2 {
+	let document = snap_data.document;
+	let document_to_viewport = document.metadata().document_to_viewport;
+	let start_viewport = document_to_viewport.transform_point2(start);
+	let mouse_position = axis_align_drag(snap_to_axis, axis, snap_data.input.mouse.position, start_viewport);
+	let aligned_document = document_to_viewport.inverse().transform_point2(mouse_position);
+	let total_mouse_delta_document = aligned_document - start;
+	let mut offset = aligned_document - current;
+	let mut best_snap = SnappedPoint::infinite_snap(aligned_document);
+
+	let bbox = Rect::point_iter(candidates.iter().map(|candidate| candidate.document_point + total_mouse_delta_document));
+
+	for (index, point) in candidates.iter().enumerate() {
+		let config = SnapTypeConfiguration {
+			bbox,
+			accept_distribution: true,
+			use_existing_candidates: index != 0,
+			..Default::default()
+		};
+
+		let mut point = point.clone();
+		point.document_point += total_mouse_delta_document;
+
+		let constrained_along_axis = snap_to_axis || axis.is_constraint();
+		let snapped = if constrained_along_axis {
+			let constraint = SnapConstraint::Line {
+				origin: point.document_point,
+				direction: total_mouse_delta_document.try_normalize().unwrap_or(DVec2::X),
+			};
+			snap_manager.constrained_snap(&snap_data, &point, constraint, config)
+		} else {
+			snap_manager.free_snap(&snap_data, &point, config)
+		};
+
+		if best_snap.other_snap_better(&snapped) {
+			offset = snapped.snapped_point_document - point.document_point + (aligned_document - current);
+			best_snap = snapped;
+		}
+	}
+
+	snap_manager.update_indicator(best_snap);
+
+	offset
+}
+
 /// Contains info on the overlays for the bounding box and transform handles
 #[derive(Clone, Debug, Default)]
 pub struct BoundingBoxManager {
@@ -379,10 +425,12 @@ pub struct BoundingBoxManager {
 	pub transform_tampered: bool,
 	/// The transform to viewport space for the bounds co-ordinates when the transformation was started.
 	pub original_bound_transform: DAffine2,
+	pub original_bounds_to_document: DAffine2,
 	pub selected_edges: Option<SelectedEdges>,
 	pub original_transforms: OriginalTransforms,
 	pub opposite_pivot: DVec2,
 	pub center_of_transformation: DVec2,
+	pub center_of_transformation_doc: DVec2,
 }
 
 impl BoundingBoxManager {

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

@@ -17,7 +17,7 @@ pub mod tool_prelude {
 	pub use crate::messages::input_mapper::utility_types::input_keyboard::{Key, MouseMotion};
 	pub use crate::messages::layout::utility_types::widget_prelude::*;
 	pub use crate::messages::prelude::*;
-	pub use crate::messages::tool::utility_types::{EventToMessageMap, Fsm, ToolActionMessageContext, ToolMetadata, ToolTransition, ToolType};
+	pub use crate::messages::tool::utility_types::{DragState, EventToMessageMap, Fsm, ToolActionMessageContext, ToolMetadata, ToolTransition, ToolType};
 	pub use crate::messages::tool::utility_types::{HintData, HintGroup, HintInfo};
 	pub use glam::{DAffine2, DVec2};
 }

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

@@ -55,6 +55,7 @@ pub struct PathToolOptions {
 pub enum PathToolMessage {
 	// Standard messages
 	Abort,
+	CanvasTransformed,
 	SelectionChanged,
 	Overlays {
 		context: OverlayContext,
@@ -511,6 +512,7 @@ impl ToolTransition for PathTool {
 	fn event_to_message_map(&self) -> EventToMessageMap {
 		EventToMessageMap {
 			tool_abort: Some(PathToolMessage::Abort.into()),
+			canvas_transformed: Some(PathToolMessage::CanvasTransformed.into()),
 			selection_changed: Some(PathToolMessage::SelectionChanged.into()),
 			overlay_provider: Some(|context| PathToolMessage::Overlays { context }.into()),
 			..Default::default()
@@ -561,7 +563,7 @@ struct PathToolData {
 	snap_manager: SnapManager,
 	lasso_polygon: Vec<DVec2>,
 	selection_mode: Option<SelectionMode>,
-	drag_start_pos: DVec2,
+	drag_start_doc: DVec2,
 	previous_mouse_position: DVec2,
 	toggle_colinear_debounce: bool,
 	opposing_handle_lengths: Option<OpposingHandleLengths>,
@@ -645,14 +647,19 @@ impl PathToolData {
 		// Convert previous mouse position to viewport space first
 		let document_to_viewport = metadata.document_to_viewport;
 		let previous_mouse = document_to_viewport.transform_point2(self.previous_mouse_position);
-		if previous_mouse == self.drag_start_pos {
+		let drag_start_vp = document_to_viewport.transform_point2(self.drag_start_doc);
+		if previous_mouse == drag_start_vp {
 			let tolerance = DVec2::splat(SELECTION_TOLERANCE);
-			[self.drag_start_pos - tolerance, self.drag_start_pos + tolerance]
+			[drag_start_vp - tolerance, drag_start_vp + tolerance]
 		} else {
-			[self.drag_start_pos, previous_mouse]
+			[drag_start_vp, previous_mouse]
 		}
 	}
 
+	fn drag_start_viewport(&self, document: &DocumentMessageHandler) -> DVec2 {
+		document.metadata().document_to_viewport.transform_point2(self.drag_start_doc)
+	}
+
 	fn update_selection_status(&mut self, shape_editor: &mut ShapeState, document: &DocumentMessageHandler) {
 		let selection_status = get_selection_status(&document.network_interface, shape_editor);
 
@@ -736,7 +743,7 @@ impl PathToolData {
 		self.double_click_handled = false;
 		self.opposing_handle_lengths = None;
 
-		self.drag_start_pos = input.mouse.position;
+		self.drag_start_doc = document.metadata().document_to_viewport.inverse().transform_point2(input.mouse.position);
 
 		if input.time - self.last_click_time > DOUBLE_CLICK_MILLISECONDS {
 			self.saved_points_before_anchor_convert_smooth_sharp.clear();
@@ -784,7 +791,7 @@ impl PathToolData {
 			}
 
 			if let Some(selected_points) = selection_info {
-				self.drag_start_pos = input.mouse.position;
+				self.drag_start_doc = document.metadata().document_to_viewport.inverse().transform_point2(input.mouse.position);
 
 				// If selected points contain only handles and there was some selection before, then it is stored and becomes restored upon release
 				let mut dragging_only_handles = true;
@@ -871,7 +878,7 @@ impl PathToolData {
 					// TODO: If the segment connected to one of the endpoints is also selected then select that point
 				}
 
-				self.drag_start_pos = input.mouse.position;
+				self.drag_start_doc = document.metadata().document_to_viewport.inverse().transform_point2(input.mouse.position);
 				let viewport_to_document = document.metadata().document_to_viewport.inverse();
 				self.previous_mouse_position = viewport_to_document.transform_point2(input.mouse.position);
 
@@ -900,15 +907,15 @@ impl PathToolData {
 
 			self.started_drawing_from_inside = true;
 
-			self.drag_start_pos = input.mouse.position;
+			self.drag_start_doc = document.metadata().document_to_viewport.inverse().transform_point2(input.mouse.position);
 			self.previous_mouse_position = document.metadata().document_to_viewport.inverse().transform_point2(input.mouse.position);
 
 			let selection_shape = if lasso_select { SelectionShapeType::Lasso } else { SelectionShapeType::Box };
 			PathToolFsmState::Drawing { selection_shape }
 		}
 		// Start drawing
 		else {
-			self.drag_start_pos = input.mouse.position;
+			self.drag_start_doc = document.metadata().document_to_viewport.inverse().transform_point2(input.mouse.position);
 			self.previous_mouse_position = document.metadata().document_to_viewport.inverse().transform_point2(input.mouse.position);
 
 			let selection_shape = if lasso_select { SelectionShapeType::Lasso } else { SelectionShapeType::Box };
@@ -1153,7 +1160,7 @@ impl PathToolData {
 	fn start_snap_along_axis(&mut self, shape_editor: &mut ShapeState, document: &DocumentMessageHandler, input: &InputPreprocessorMessageHandler, responses: &mut VecDeque<Message>) {
 		// Find the negative delta to take the point to the drag start position
 		let current_mouse = input.mouse.position;
-		let drag_start = self.drag_start_pos;
+		let drag_start = self.drag_start_viewport(document);
 		let opposite_delta = drag_start - current_mouse;
 
 		shape_editor.move_selected_points_and_segments(None, document, opposite_delta, false, true, false, None, false, responses);
@@ -1174,7 +1181,7 @@ impl PathToolData {
 	fn stop_snap_along_axis(&mut self, shape_editor: &mut ShapeState, document: &DocumentMessageHandler, input: &InputPreprocessorMessageHandler, responses: &mut VecDeque<Message>) {
 		// Calculate the negative delta of the selection and move it back to the drag start
 		let current_mouse = input.mouse.position;
-		let drag_start = self.drag_start_pos;
+		let drag_start = self.drag_start_viewport(document);
 
 		let opposite_delta = drag_start - current_mouse;
 		let Some(axis) = self.snapping_axis else { return };
@@ -1463,7 +1470,7 @@ impl PathToolData {
 		let mut was_alt_dragging = false;
 
 		if self.snapping_axis.is_none() {
-			if self.alt_clicked_on_anchor && !self.alt_dragging_from_anchor && self.drag_start_pos.distance(input.mouse.position) > DRAG_THRESHOLD {
+			if self.alt_clicked_on_anchor && !self.alt_dragging_from_anchor && self.drag_start_viewport(document).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 {
@@ -1485,7 +1492,7 @@ impl PathToolData {
 						return;
 					};
 
-					let delta = input.mouse.position - self.drag_start_pos;
+					let delta = input.mouse.position - self.drag_start_viewport(document);
 					let handle = if delta.dot(tangent1) >= delta.dot(tangent2) {
 						segment1.to_manipulator_point()
 					} else {
@@ -1528,7 +1535,7 @@ impl PathToolData {
 		// 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 };
-			let total_delta = self.drag_start_pos - input.mouse.position;
+			let total_delta = self.drag_start_viewport(document) - input.mouse.position;
 
 			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);
@@ -1706,7 +1713,7 @@ impl Fsm for PathToolFsmState {
 			}
 			(_, PathToolMessage::Overlays { context: mut overlay_context }) => {
 				// Set this to show ghost line only if drag actually happened
-				if matches!(self, Self::Dragging(_)) && tool_data.drag_start_pos.distance(input.mouse.position) > DRAG_THRESHOLD {
+				if matches!(self, Self::Dragging(_)) && tool_data.drag_start_viewport(document).distance(input.mouse.position) > DRAG_THRESHOLD {
 					for (outline, layer) in &tool_data.ghost_outline {
 						let transform = document.metadata().transform_to_viewport(*layer);
 						overlay_context.outline(outline.iter(), transform, Some(COLOR_OVERLAY_GRAY));
@@ -1904,7 +1911,8 @@ impl Fsm for PathToolFsmState {
 						let (points_inside, segments_inside) = match selection_shape {
 							SelectionShapeType::Box => {
 								let previous_mouse = document.metadata().document_to_viewport.transform_point2(tool_data.previous_mouse_position);
-								let bbox = Rect::new(tool_data.drag_start_pos.x, tool_data.drag_start_pos.y, previous_mouse.x, previous_mouse.y).abs();
+								let drag_start_vp = tool_data.drag_start_viewport(document);
+								let bbox = Rect::new(drag_start_vp.x, drag_start_vp.y, previous_mouse.x, previous_mouse.y).abs();
 								shape_editor.get_inside_points_and_segments(
 									&document.network_interface,
 									SelectionShape::Box(bbox),
@@ -1971,7 +1979,7 @@ impl Fsm for PathToolFsmState {
 						// Draw the snapping axis lines
 						if tool_data.snapping_axis.is_some() {
 							let Some(axis) = tool_data.snapping_axis else { return self };
-							let origin = tool_data.drag_start_pos;
+							let origin = tool_data.drag_start_viewport(document);
 							let viewport_diagonal = viewport.size().into_dvec2().length();
 
 							match axis {
@@ -2099,11 +2107,11 @@ impl Fsm for PathToolFsmState {
 				let selected_only_handles = !shape_editor.selected_points().any(|point| matches!(point, ManipulatorPointId::Anchor(_)));
 				tool_data.stored_selection = None;
 
-				if !tool_data.saved_selection_before_handle_drag.is_empty() && (tool_data.drag_start_pos.distance(input.mouse.position) > DRAG_THRESHOLD) && (selected_only_handles) {
+				if !tool_data.saved_selection_before_handle_drag.is_empty() && (tool_data.drag_start_viewport(document).distance(input.mouse.position) > DRAG_THRESHOLD) && (selected_only_handles) {
 					tool_data.handle_drag_toggle = true;
 				}
 
-				if tool_data.drag_start_pos.distance(input.mouse.position) > DRAG_THRESHOLD {
+				if tool_data.drag_start_viewport(document).distance(input.mouse.position) > DRAG_THRESHOLD {
 					tool_data.molding_segment = true;
 				}
 
@@ -2245,15 +2253,15 @@ impl Fsm for PathToolFsmState {
 			(PathToolFsmState::Drawing { selection_shape: selection_type }, PathToolMessage::PointerOutsideViewport { .. }) => {
 				// Auto-panning
 				if let Some(offset) = tool_data.auto_panning.shift_viewport(input, viewport, responses) {
-					tool_data.drag_start_pos += offset;
+					tool_data.drag_start_doc += document.metadata().document_to_viewport.inverse().transform_vector2(offset);
 				}
 
 				PathToolFsmState::Drawing { selection_shape: selection_type }
 			}
 			(PathToolFsmState::Dragging(dragging_state), PathToolMessage::PointerOutsideViewport { .. }) => {
 				// Auto-panning
 				if let Some(offset) = tool_data.auto_panning.shift_viewport(input, viewport, responses) {
-					tool_data.drag_start_pos += offset;
+					tool_data.drag_start_doc += document.metadata().document_to_viewport.inverse().transform_vector2(offset);
 				}
 
 				PathToolFsmState::Dragging(dragging_state)
@@ -2314,7 +2322,7 @@ impl Fsm for PathToolFsmState {
 
 				let document_to_viewport = document.metadata().document_to_viewport;
 				let previous_mouse = document_to_viewport.transform_point2(tool_data.previous_mouse_position);
-				if tool_data.drag_start_pos == previous_mouse {
+				if tool_data.drag_start_viewport(document) == previous_mouse {
 					responses.add(NodeGraphMessage::SelectedNodesSet { nodes: vec![] });
 				} else {
 					let selection_mode = match tool_action_data.preferences.get_selection_mode() {
@@ -2324,7 +2332,8 @@ impl Fsm for PathToolFsmState {
 
 					match selection_shape {
 						SelectionShapeType::Box => {
-							let bbox = Rect::new(tool_data.drag_start_pos.x, tool_data.drag_start_pos.y, previous_mouse.x, previous_mouse.y).abs();
+							let drag_start_vp = tool_data.drag_start_viewport(document);
+							let bbox = Rect::new(drag_start_vp.x, drag_start_vp.y, previous_mouse.x, previous_mouse.y).abs();
 
 							shape_editor.select_all_in_shape(
 								&document.network_interface,
@@ -2355,7 +2364,7 @@ impl Fsm for PathToolFsmState {
 				PathToolFsmState::Ready
 			}
 			(PathToolFsmState::Dragging { .. }, PathToolMessage::Escape | PathToolMessage::RightClick) => {
-				if tool_data.handle_drag_toggle && tool_data.drag_start_pos.distance(input.mouse.position) > DRAG_THRESHOLD {
+				if tool_data.handle_drag_toggle && tool_data.drag_start_viewport(document).distance(input.mouse.position) > DRAG_THRESHOLD {
 					shape_editor.deselect_all_points();
 					shape_editor.deselect_all_segments();
 
@@ -2410,7 +2419,7 @@ impl Fsm for PathToolFsmState {
 				};
 				tool_data.started_drawing_from_inside = false;
 
-				if tool_data.drag_start_pos.distance(previous_mouse) < 1e-8 {
+				if tool_data.drag_start_viewport(document).distance(previous_mouse) < 1e-8 {
 					// Clicked inside or outside the shape then deselect all of the points/segments
 					if document.click(input, viewport).is_some() && tool_data.stored_selection.is_none() {
 						tool_data.stored_selection = Some(shape_editor.selected_shape_state.clone());
@@ -2421,7 +2430,8 @@ impl Fsm for PathToolFsmState {
 				} else {
 					match selection_shape {
 						SelectionShapeType::Box => {
-							let bbox = Rect::new(tool_data.drag_start_pos.x, tool_data.drag_start_pos.y, previous_mouse.x, previous_mouse.y).abs();
+							let drag_start_vp = tool_data.drag_start_viewport(document);
+							let bbox = Rect::new(drag_start_vp.x, drag_start_vp.y, previous_mouse.x, previous_mouse.y).abs();
 
 							shape_editor.select_all_in_shape(
 								&document.network_interface,
@@ -2454,7 +2464,7 @@ impl Fsm for PathToolFsmState {
 			(_, PathToolMessage::DragStop { extend_selection, .. }) => {
 				tool_data.ghost_outline.clear();
 				let extend_selection = input.keyboard.get(extend_selection as usize);
-				let drag_occurred = tool_data.drag_start_pos.distance(input.mouse.position) > DRAG_THRESHOLD;
+				let drag_occurred = tool_data.drag_start_viewport(document).distance(input.mouse.position) > DRAG_THRESHOLD;
 				let mut segment_dissolved = false;
 				let mut point_inserted = false;
 
@@ -2585,7 +2595,7 @@ impl Fsm for PathToolFsmState {
 					}
 				}
 				// Deselect all points if the user clicks the filled region of the shape
-				else if tool_data.drag_start_pos.distance(input.mouse.position) <= DRAG_THRESHOLD {
+				else if tool_data.drag_start_viewport(document).distance(input.mouse.position) <= DRAG_THRESHOLD {
 					shape_editor.deselect_all_points();
 					shape_editor.deselect_all_segments();
 				}
@@ -3037,7 +3047,7 @@ impl Fsm for PathToolFsmState {
 
 				if nearest_point.is_some() {
 					// Flip the selected point between smooth and sharp
-					if !tool_data.double_click_handled && tool_data.drag_start_pos.distance(input.mouse.position) <= DRAG_THRESHOLD {
+					if !tool_data.double_click_handled && tool_data.drag_start_viewport(document).distance(input.mouse.position) <= DRAG_THRESHOLD {
 						responses.add(DocumentMessage::StartTransaction);
 
 						shape_editor.select_points_by_layer_and_id(&tool_data.saved_points_before_anchor_convert_smooth_sharp);
@@ -3119,6 +3129,42 @@ impl Fsm for PathToolFsmState {
 
 				PathToolFsmState::Ready
 			}
+			// PTZ handling: re-emit PointerMove to recompute positions with updated document_to_viewport
+			(PathToolFsmState::Dragging(dragging_state), PathToolMessage::CanvasTransformed) => {
+				let modifier_keys = PathToolMessage::PointerMove {
+					equidistant: Key::Alt,
+					toggle_colinear: Key::KeyC,
+					move_anchor_with_handles: Key::Space,
+					snap_angle: Key::Control,
+					lock_angle: Key::Shift,
+					delete_segment: Key::Backspace,
+					break_colinear_molding: Key::Tab,
+					segment_editing_modifier: Key::Alt,
+				};
+				responses.add(modifier_keys);
+				responses.add(OverlaysMessage::Draw);
+				PathToolFsmState::Dragging(dragging_state)
+			}
+			(PathToolFsmState::Drawing { selection_shape }, PathToolMessage::CanvasTransformed) => {
+				let modifier_keys = PathToolMessage::PointerMove {
+					equidistant: Key::Alt,
+					toggle_colinear: Key::KeyC,
+					move_anchor_with_handles: Key::Space,
+					snap_angle: Key::Control,
+					lock_angle: Key::Shift,
+					delete_segment: Key::Backspace,
+					break_colinear_molding: Key::Tab,
+					segment_editing_modifier: Key::Alt,
+				};
+				responses.add(modifier_keys);
+				responses.add(OverlaysMessage::Draw);
+				PathToolFsmState::Drawing { selection_shape }
+			}
+			(PathToolFsmState::SlidingPoint, PathToolMessage::CanvasTransformed) => {
+				responses.add(OverlaysMessage::Draw);
+				PathToolFsmState::SlidingPoint
+			}
+			(_, PathToolMessage::CanvasTransformed) => self,
 			(_, PathToolMessage::Abort) => {
 				responses.add(OverlaysMessage::Draw);
 				PathToolFsmState::Ready