Fix Alt-based quick measurement to show document space coordinates instead of viewport space (#2995)

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

Author: vineetpuranik

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

@@ -43,18 +43,19 @@ fn draw_line_with_length(line_start: DVec2, line_end: DVec2, transform: DAffine2
 	}
 }
 
-/// Draws a dashed outline around a rectangle to visualize the AABB
+/// Draws a dashed outline around the given rectangle (assumed to be in document space).
+/// The provided transform is applied to convert coordinates (e.g., to viewport space) during rendering.
 fn draw_dashed_rect_outline(rect: Rect, transform: DAffine2, overlay_context: &mut OverlayContext) {
 	let min = rect.min();
 	let max = rect.max();
 
-	// Create the four corners of the rectangle
-	let top_left = transform.transform_point2(DVec2::new(min.x, min.y));
-	let top_right = transform.transform_point2(DVec2::new(max.x, min.y));
-	let bottom_right = transform.transform_point2(DVec2::new(max.x, max.y));
-	let bottom_left = transform.transform_point2(DVec2::new(min.x, max.y));
+	// Define corners in document space
+	let top_left = DVec2::new(min.x, min.y);
+	let top_right = DVec2::new(max.x, min.y);
+	let bottom_right = DVec2::new(max.x, max.y);
+	let bottom_left = DVec2::new(min.x, max.y);
 
-	// Draw the four sides as dashed lines
+	// Draw each edge using document-space coordinates; transform is applied inside draw_dashed_line
 	draw_dashed_line(top_left, top_right, transform, overlay_context);
 	draw_dashed_line(top_right, bottom_right, transform, overlay_context);
 	draw_dashed_line(bottom_right, bottom_left, transform, overlay_context);

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

@@ -691,32 +691,28 @@ impl Fsm for SelectToolFsmState {
 						// Measure with Alt held down
 						// TODO: Don't use `Key::Alt` directly, instead take it as a variable from the input mappings list like in all other places
 						if overlay_context.visibility_settings.quick_measurement() && !matches!(self, Self::ResizingBounds { .. }) && input.keyboard.get(Key::Alt as usize) {
-							// Get all selected layers and compute their viewport-aligned AABB
-							let selected_bounds_viewport = document
+							// Compute document-space bounding box (AABB) of all selected visible & unlocked layers
+							let selected_bounds_doc_space = document
 								.network_interface
 								.selected_nodes()
 								.selected_visible_and_unlocked_layers(&document.network_interface)
+								// Exclude layers that are artboards
 								.filter(|layer| !document.network_interface.is_artboard(&layer.to_node(), &[]))
-								.filter_map(|layer| {
-									// Get the layer's bounding box in its local space
-									let local_bounds = document.metadata().bounding_box_with_transform(layer, DAffine2::IDENTITY)?;
-									// Transform the bounds directly to viewport space
-									let viewport_quad = document.metadata().transform_to_viewport(layer) * Quad::from_box(local_bounds);
-									// Convert the quad to an AABB in viewport space
-									Some(Rect::from_box(viewport_quad.bounding_box()))
-								})
+								// For each remaining layer, try to get its document-space bounding box and convert it to a Rect
+								.filter_map(|layer| document.metadata().bounding_box_document(layer).map(Rect::from_box))
+								// Combine all individual bounding boxes into one overall bounding box that contains all selected layers
 								.reduce(Rect::combine_bounds);
 
-							// Get the hovered layer's viewport-aligned AABB
-							let hovered_bounds_viewport = document.metadata().bounding_box_with_transform(layer, DAffine2::IDENTITY).map(|bounds| {
-								let viewport_quad = document.metadata().transform_to_viewport(layer) * Quad::from_box(bounds);
-								Rect::from_box(viewport_quad.bounding_box())
-							});
+							// Compute document-space bounding box (AABB) of the currently hovered layer
+							let hovered_bounds_doc_space = document.metadata().bounding_box_document(layer);
 
-							// Use the viewport-aligned AABBs for measurement
-							if let (Some(selected_bounds), Some(hovered_bounds)) = (selected_bounds_viewport, hovered_bounds_viewport) {
-								// Since we're already in viewport space, use identity transform
-								measure::overlay(selected_bounds, hovered_bounds, DAffine2::IDENTITY, DAffine2::IDENTITY, &mut overlay_context);
+							// If both selected and hovered bounds exist, overlay measurement lines
+							if let (Some(selected_bounds), Some(hovered_bounds)) = (selected_bounds_doc_space, hovered_bounds_doc_space.map(Rect::from_box)) {
+								// Both `selected_bounds` and `hovered_bounds` are in document space.
+								// To correctly render overlay lines in the UI (which is in viewport space), we need to transform both rectangles from document to viewport space.
+								// Therefore, we pass `document_to_viewport` as both the `transform` and `document_to_viewport` parameters.
+								let document_to_viewport = document.metadata().document_to_viewport;
+								measure::overlay(selected_bounds, hovered_bounds, document_to_viewport, document_to_viewport, &mut overlay_context);
 							}
 						}
 					}