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};
 }