Fix clipping masks, click targets, and bounds when rendering Vector[] and flattened graphic wrappers (#4429)

* Honor clipping masks when rendering Vector[] lists, not just Graphic[] groups

* Keep per-layer click targets when a Vector[] round-trips through a Graphic[] wrapper

* Skip the rebuild and the merged-layers snapshot when flattening a lone anonymous graphic wrapper

* Fix a group's bounds excluding its raster children and stretching to the origin

* Fix SVG clipping masks landing in the wrong space when sibling layers differ in transform

node-graph/libraries/graphic-types/src/graphic.rs

@@ -111,9 +111,27 @@ impl From<List<String>> for Graphic {
 	}
 }
 
+/// Whether the list is a single leaf item carrying nothing to compose onto its contents, so flattening it
+/// collapses no structure and rebuilding or snapshotting the result would be busywork.
+pub fn is_lone_anonymous_leaf(content: &List<Graphic>) -> bool {
+	content.len() == 1
+		&& !matches!(content.element(0), Some(Graphic::Graphic(_)))
+		&& content.attribute::<DAffine2>(ATTR_TRANSFORM, 0).is_none()
+		&& content.attribute::<f64>(ATTR_OPACITY, 0).is_none()
+		&& content.attribute::<f64>(ATTR_OPACITY_FILL, 0).is_none()
+		&& content.attribute::<NodeIdPath>(ATTR_EDITOR_LAYER_PATH, 0).is_none()
+}
+
 /// Deeply flattens a `List<Graphic>`, collecting only elements matching a specific variant (extracted by `extract_variant`)
 /// and discarding all other non-matching content. Recursion through `Graphic::Graphic` sub-`List`s composes transforms and opacity.
 fn flatten_graphic_list<T>(content: List<Graphic>, extract_variant: fn(Graphic) -> Option<List<T>>) -> List<T> {
+	// Its list is already the flat answer, so hand it back rather than rebuilding it item by item
+	if is_lone_anonymous_leaf(&content) {
+		let Some(item) = content.into_iter().next() else { return List::new() };
+
+		return extract_variant(item.into_element()).unwrap_or_default();
+	}
+
 	fn flatten_recursive<T>(output: &mut List<T>, current_graphic_list: List<Graphic>, extract_variant: fn(Graphic) -> Option<List<T>>) {
 		for current_graphic_item in current_graphic_list.into_iter() {
 			// Whether the parent carries each attribute: a structural fact (column presence), never a value comparison.
@@ -133,6 +151,12 @@ fn flatten_graphic_list<T>(content: List<Graphic>, extract_variant: fn(Graphic)
 				// Compose the parent's transform/opacity/fill onto each child, but only for attributes the parent carries.
 				// A child lacking one is padded with the composition identity (`1.` for opacity/fill, identity for transform), so composing through it is a no-op.
 				Graphic::Graphic(mut sub_list) => {
+					// A group's first child has no preceding sibling, so its clipping flag is inert until splicing
+					// hands it the group's own predecessor. Clear it (keeping the column) to stay clip-neutral.
+					if sub_list.attribute::<bool>(ATTR_CLIPPING_MASK, 0).is_some() {
+						sub_list.set_attribute(ATTR_CLIPPING_MASK, 0, false);
+					}
+
 					if parent_has_transform {
 						for v in sub_list.iter_attribute_values_mut_or_default::<DAffine2>(ATTR_TRANSFORM) {
 							*v = current_transform * *v;
@@ -304,14 +328,9 @@ impl IntoGraphicList for List<Graphic> {
 
 impl IntoGraphicList for List<Vector> {
 	fn into_graphic_list(self) -> List<Graphic> {
-		// Propagate the `editor:layer_path` column (if present) from item 0 onto the wrapper Graphic item so a
+		// A synthetic container, not a real group layer, so it carries no `editor:layer_path` that would
-		// subsequent `flatten_graphic_list` doesn't drop the inner Vector's layer stamp
+		// overwrite the inner items' own stamps when flattened back out
-		let layer_path = self.attribute::<NodeIdPath>(ATTR_EDITOR_LAYER_PATH, 0).cloned();
+		List::new_from_element(Graphic::Vector(self))
-		let mut graphic_list = List::new_from_element(Graphic::Vector(self));
-		if let Some(layer_path) = layer_path {
-			graphic_list.set_attribute(ATTR_EDITOR_LAYER_PATH, 0, layer_path);
-		}
-		graphic_list
 	}
 }
 
@@ -341,12 +360,7 @@ impl IntoGraphicList for List<Gradient> {
 
 impl IntoGraphicList for List<String> {
 	fn into_graphic_list(self) -> List<Graphic> {
-		let layer_path = self.attribute::<NodeIdPath>(ATTR_EDITOR_LAYER_PATH, 0).cloned();
+		List::new_from_element(Graphic::Text(self))
-		let mut graphic_list = List::new_from_element(Graphic::Text(self));
-		if let Some(layer_path) = layer_path {
-			graphic_list.set_attribute(ATTR_EDITOR_LAYER_PATH, 0, layer_path);
-		}
-		graphic_list
 	}
 }
 
@@ -634,11 +648,52 @@ impl<T: Clone> OmitIndex for List<T> {
 mod tests {
 	use super::*;
 	use core_types::list::List;
+	use core_types::uuid::NodeId;
 
 	fn vector_graphic() -> Graphic {
 		Graphic::Vector(List::new_from_element(Vector::default()))
 	}
 
+	fn vector_list_stamped_with_layers(layers: [u64; 2]) -> List<Vector> {
+		let mut list = List::new();
+
+		for layer in layers {
+			let mut item = Item::new_from_element(Vector::default());
+			item.set_attribute(ATTR_EDITOR_LAYER_PATH, NodeIdPath::from(vec![NodeId(layer)]));
+			list.push(item);
+		}
+
+		list
+	}
+
+	// The wrapper minted for a typed list is a container rather than a layer, so it must never claim a layer path
+	#[test]
+	fn wrapping_a_typed_list_leaves_the_wrapper_anonymous() {
+		let graphic_list = vector_list_stamped_with_layers([7, 9]).into_graphic_list();
+
+		assert_eq!(graphic_list.len(), 1);
+		assert!(!graphic_list.attribute_keys().any(|key| key == ATTR_EDITOR_LAYER_PATH));
+	}
+
+	// Round-tripping through that wrapper must not collapse the items' distinct stamps onto item 0's
+	#[test]
+	fn round_trip_through_the_wrapper_preserves_per_item_layer_paths() {
+		let flattened: List<Vector> = vector_list_stamped_with_layers([7, 9]).into_flattened_list();
+
+		let layers = (0..flattened.len())
+			.map(|index| {
+				flattened
+					.attribute_cloned_or_default::<NodeIdPath>(ATTR_EDITOR_LAYER_PATH, index)
+					.0
+					.iter_element_values()
+					.next_back()
+					.copied()
+			})
+			.collect::<Vec<_>>();
+
+		assert_eq!(layers, [Some(NodeId(7)), Some(NodeId(9))]);
+	}
+
 	// Flattening must not invent attribute columns that neither the parent graphic nor the child carried
 	#[test]
 	fn flatten_does_not_invent_attributes() {

node-graph/libraries/rendering/src/renderer.rs

@@ -940,12 +940,41 @@ impl Render for List<Graphic> {
 			let opacity_fill_attr: f64 = self.attribute_cloned_or(ATTR_OPACITY_FILL, index, 1.);
 			let element = self.element(index).unwrap();
 
+			let matrix = format_transform_matrix(transform);
+			let next_clips = index + 1 < self.len() && self.element(index + 1).unwrap().had_clip_enabled();
+			let mut masked_by = None;
+
+			if next_clips && mask_state.is_none() {
+				let uuid = generate_uuid();
+				let mask_type = if element.can_reduce_to_clip_path() { MaskType::Clip } else { MaskType::Mask };
+
+				let mut svg = SvgRender::new();
+				element.render_svg(&mut svg, &render_params.for_clipper());
+
+				// The def is resolved in this list's space, so the masker's own transform has to be baked into it
+				let masker = match matrix.is_empty() {
+					true => svg.svg.to_svg_string(),
+					false => format!(r##"<g transform="{matrix}">{}</g>"##, svg.svg.to_svg_string()),
+				};
+
+				render.svg_defs.push_str(&svg.svg_defs);
+				mask_type.write_to_defs(&mut render.svg_defs, uuid, masker);
+
+				mask_state = Some((uuid, mask_type));
+			} else if let Some((uuid, mask_type)) = mask_state {
+				if !next_clips {
+					mask_state = None;
+				}
+
+				masked_by = Some((mask_type.to_attribute(), format!("url(#mask-{uuid})")));
+			}
+
+			let render_item = |render: &mut SvgRender| {
 				render.parent_tag(
 					"g",
 					|attributes| {
-					let matrix = format_transform_matrix(transform);
 						if !matrix.is_empty() {
-						attributes.push(ATTR_TRANSFORM, matrix);
+							attributes.push(ATTR_TRANSFORM, matrix.clone());
 						}
 
 						let opacity = (opacity_attr * if render_params.for_mask { 1. } else { opacity_fill_attr }) as f32;
@@ -956,33 +985,16 @@ impl Render for List<Graphic> {
 						if blend_mode != BlendMode::default() {
 							attributes.push("style", blend_mode.render());
 						}
-
-					let next_clips = index + 1 < self.len() && self.element(index + 1).unwrap().had_clip_enabled();
-
-					if next_clips && mask_state.is_none() {
-						let uuid = generate_uuid();
-						let mask_type = if element.can_reduce_to_clip_path() { MaskType::Clip } else { MaskType::Mask };
-						mask_state = Some((uuid, mask_type));
-						let mut svg = SvgRender::new();
-						element.render_svg(&mut svg, &render_params.for_clipper());
-
-						write!(&mut attributes.0.svg_defs, r##"{}"##, svg.svg_defs).unwrap();
-						mask_type.write_to_defs(&mut attributes.0.svg_defs, uuid, svg.svg.to_svg_string());
-					} else if let Some((uuid, mask_type)) = mask_state {
-						if !next_clips {
-							mask_state = None;
-						}
-
-						let id = format!("mask-{uuid}");
-						let selector = format!("url(#{id})");
-
-						attributes.push(mask_type.to_attribute(), selector);
-					}
-				},
-				|render| {
-					element.render_svg(render, render_params);
 					},
+					|render| element.render_svg(render, render_params),
 				);
+			};
+
+			// The mask rides an untransformed wrapper so it resolves in this list's space rather than the item's own
+			match masked_by {
+				Some((attribute, selector)) => render.parent_tag("g", |attributes| attributes.push(attribute, selector), render_item),
+				None => render_item(render),
+			}
 		}
 	}
 
@@ -1156,14 +1168,12 @@ impl Render for List<Graphic> {
 	}
 }
 
-impl Render for List<Vector> {
+/// Emits one item of a `List<Vector>` as SVG, with no wrapping group of its own.
-	fn render_svg(&self, render: &mut SvgRender, render_params: &RenderParams) {
+fn render_vector_item_svg(list: &List<Vector>, index: usize, vector: &Vector, render: &mut SvgRender, render_params: &RenderParams) {
-		for index in 0..self.len() {
+	let item_transform: DAffine2 = list.attribute_cloned_or_default(ATTR_TRANSFORM, index);
-			let Some(vector) = self.element(index) else { continue };
+	let blend_mode_attr: BlendMode = list.attribute_cloned_or_default(ATTR_BLEND_MODE, index);
-			let item_transform: DAffine2 = self.attribute_cloned_or_default(ATTR_TRANSFORM, index);
+	let opacity_attr: f64 = list.attribute_cloned_or(ATTR_OPACITY, index, 1.);
-			let blend_mode_attr: BlendMode = self.attribute_cloned_or_default(ATTR_BLEND_MODE, index);
+	let opacity_fill_attr: f64 = list.attribute_cloned_or(ATTR_OPACITY_FILL, index, 1.);
-			let opacity_attr: f64 = self.attribute_cloned_or(ATTR_OPACITY, index, 1.);
-			let opacity_fill_attr: f64 = self.attribute_cloned_or(ATTR_OPACITY_FILL, index, 1.);
 
 	// Only consider strokes with non-zero weight, since default strokes with zero weight would prevent assigning the correct stroke transform
 	let has_real_stroke = vector.stroke.as_ref().filter(|stroke| stroke.weight() > 0.);
@@ -1192,10 +1202,10 @@ impl Render for List<Vector> {
 		MaskType::Mask
 	};
 
-			let fill_graphic_list = graphic_list_at(self, index, ATTR_FILL);
+	let fill_graphic_list = graphic_list_at(list, index, ATTR_FILL);
 	let fill_graphic = fill_graphic_list.as_ref().and_then(|l| l.element(0));
 
-			let stroke_graphic_list = graphic_list_at(self, index, ATTR_STROKE);
+	let stroke_graphic_list = graphic_list_at(list, index, ATTR_STROKE);
 	let stroke_graphic = stroke_graphic_list.as_ref().and_then(|l| l.element(0));
 
 	let path_is_closed = vector.stroke_bezier_paths().all(|path| path.closed());
@@ -1369,9 +1379,52 @@ impl Render for List<Vector> {
 		);
 	}
 }
+
+impl Render for List<Vector> {
+	fn render_svg(&self, render: &mut SvgRender, render_params: &RenderParams) {
+		let mut clip_mask_state: Option<(u64, MaskType)> = None;
+
+		for index in 0..self.len() {
+			let Some(vector) = self.element(index) else { continue };
+
+			// A clip-flagged item is masked by its nearest preceding unflagged sibling, which a consecutive run shares
+			let next_clips = index + 1 < self.len() && self.attribute_cloned_or_default::<bool>(ATTR_CLIPPING_MASK, index + 1);
+			let mut masked_by = None;
+
+			if next_clips && clip_mask_state.is_none() {
+				let masker = Graphic::Vector(List::new_from_item(Item::from_parts(vector.clone(), self.clone_item_attributes(index))));
+				let mask_type = if masker.can_reduce_to_clip_path() { MaskType::Clip } else { MaskType::Mask };
+				let uuid = generate_uuid();
+
+				let mut masker_svg = SvgRender::new();
+				masker.render_svg(&mut masker_svg, &render_params.for_clipper());
+				render.svg_defs.push_str(&masker_svg.svg_defs);
+				mask_type.write_to_defs(&mut render.svg_defs, uuid, masker_svg.svg.to_svg_string());
+
+				clip_mask_state = Some((uuid, mask_type));
+			} else if let Some((uuid, mask_type)) = clip_mask_state {
+				if !next_clips {
+					clip_mask_state = None;
+				}
+
+				masked_by = Some((mask_type.to_attribute(), format!("url(#mask-{uuid})")));
+			}
+
+			// Item geometry is baked into the path data instead of a group transform, so mask coordinates line up
+			match masked_by {
+				Some((attribute, selector)) => render.parent_tag(
+					"g",
+					|attributes| attributes.push(attribute, selector),
+					|render| render_vector_item_svg(self, index, vector, render, render_params),
+				),
+				None => render_vector_item_svg(self, index, vector, render, render_params),
+			}
+		}
 	}
 
 	fn render_to_vello(&self, scene: &mut Scene, parent_transform: DAffine2, context: &mut RenderContext, render_params: &RenderParams) {
+		let mut clip_masker: Option<List<Vector>> = None;
+
 		for index in 0..self.len() {
 			use graphic_types::vector_types::vector;
 
@@ -1423,23 +1476,53 @@ impl Render for List<Vector> {
 			let can_draw_aligned_stroke =
 				!stroke_fully_transparent && stroke.is_some_and(|s| s.has_renderable_stroke() && s.align.is_not_centered()) && element.stroke_bezier_paths().all(|p| p.closed());
 
+			// A clip-flagged item is masked by its nearest preceding unflagged sibling, which a consecutive run shares
+			let next_clips = index + 1 < self.len() && self.attribute_cloned_or_default::<bool>(ATTR_CLIPPING_MASK, index + 1);
+
 			let opacity = (opacity_attr * if render_params.for_mask { 1. } else { opacity_fill_attr }) as f32;
-			if opacity < 1. || blend_mode_attr != BlendMode::default() {
+			let needs_blend_layer = opacity < 1. || blend_mode_attr != BlendMode::default();
-				layer = true;
+
+			// Shared by the blend and clipping layers below, so it is only worth deriving when one of them is pushed
+			let layer_geometry = (needs_blend_layer || clip_masker.is_some()).then(|| {
 				// `max_aabb_inflation` is in `applied_stroke_transform`-space; `layer_bounds` is path-local and `push_layer` re-applies `multiplied_transform`.
 				// Divide by the smaller axial scale to cover the stroke in both axes after Vello's transform. Skip on a degenerate transform.
 				let (_, smallest_scale) = singular_values(applied_stroke_transform);
 				let stroke_inflation = stroke.map_or(0., |s| s.max_aabb_inflation(can_draw_aligned_stroke));
 				let inflate_amount = if smallest_scale > 0. { stroke_inflation / smallest_scale } else { 0. };
-				let quad = Quad::from_box(layer_bounds).inflate(inflate_amount);
+				let bounds = Quad::from_box(layer_bounds).inflate(inflate_amount).bounding_box();
-				let layer_bounds = quad.bounding_box();
+
+				(
+					kurbo::Affine::new(multiplied_transform.to_cols_array()),
+					kurbo::Rect::new(bounds[0].x, bounds[0].y, bounds[1].x, bounds[1].y),
+				)
+			});
+
+			if needs_blend_layer && let Some((layer_affine, layer_rect)) = layer_geometry {
+				layer = true;
+				scene.push_layer(peniko::Fill::NonZero, peniko::BlendMode::new(blend_mode, peniko::Compose::SrcOver), opacity, layer_affine, &layer_rect);
+			}
+
+			// Pushed inside the blend layer so the mask cuts this item's own paint rather than the composited result
+			let mut clip_layers = false;
+			if next_clips && clip_masker.is_none() {
+				clip_masker = Some(List::new_from_item(Item::from_parts(element.clone(), self.clone_item_attributes(index))));
+			} else if let Some(masker) = clip_masker.as_ref() {
+				if let Some((layer_affine, layer_rect)) = layer_geometry {
+					scene.push_layer(peniko::Fill::NonZero, peniko::Mix::Normal, 1., layer_affine, &layer_rect);
+					masker.render_to_vello(scene, parent_transform, context, &render_params.for_clipper());
 					scene.push_layer(
 						peniko::Fill::NonZero,
-					peniko::BlendMode::new(blend_mode, peniko::Compose::SrcOver),
+						peniko::BlendMode::new(peniko::Mix::Normal, peniko::Compose::SrcIn),
-					opacity,
+						1.,
-					kurbo::Affine::new(multiplied_transform.to_cols_array()),
+						layer_affine,
-					&kurbo::Rect::new(layer_bounds[0].x, layer_bounds[0].y, layer_bounds[1].x, layer_bounds[1].y),
+						&layer_rect,
 					);
+					clip_layers = true;
+				}
+
+				if !next_clips {
+					clip_masker = None;
+				}
 			}
 
 			let use_layer = can_draw_aligned_stroke;
@@ -1643,6 +1726,11 @@ impl Render for List<Vector> {
 				}
 			}
 
+			if clip_layers {
+				scene.pop_layer();
+				scene.pop_layer();
+			}
+
 			// If we pushed a layer for opacity or a blend mode, we need to pop it
 			if layer {
 				scene.pop_layer();
@@ -1652,17 +1740,8 @@ impl Render for List<Vector> {
 
 	fn collect_metadata(&self, metadata: &mut RenderMetadata, footprint: Footprint, caller_element_id: Option<NodeId>) {
 		// Aggregate all items' targets per element_id so multi-item lists (e.g. the "Text to Vector Glyphs" node) produce hit areas for every glyph.
-		// Targets are baked relative to item 0's transform since `Graphic::collect_metadata` records that as `local_transforms[element_id]`.
+		// Targets are baked relative to the first item carrying each element_id, since that is the transform recorded as its `local_transforms` entry.
-		let item_zero_transform: DAffine2 = if !self.is_empty() {
+		let mut reference_transforms: HashMap<NodeId, DAffine2> = HashMap::new();
-			self.attribute_cloned_or_default(ATTR_TRANSFORM, 0)
-		} else {
-			DAffine2::IDENTITY
-		};
-		let item_zero_inverse = if transform_is_invertible(item_zero_transform) {
-			item_zero_transform.inverse()
-		} else {
-			DAffine2::IDENTITY
-		};
 
 		let mut accumulated_click_targets: HashMap<NodeId, Vec<Arc<ClickTarget>>> = HashMap::new();
 		let mut accumulated_outlines: HashMap<NodeId, Vec<Arc<ClickTarget>>> = HashMap::new();
@@ -1674,18 +1753,17 @@ impl Render for List<Vector> {
 			let layer = layer_path.iter_element_values().next_back().copied();
 
 			if let Some(element_id) = caller_element_id.or(layer) {
-				// When recovering element_id from the item's editor:layer_path tag (because the caller
+				let reference_transform = *reference_transforms.entry(element_id).or_insert(transform);
-				// passed None), also store the transform metadata that Graphic::collect_metadata
+				let reference_inverse = if transform_is_invertible(reference_transform) {
-				// normally provides but skipped due to the None element_id.
+					reference_transform.inverse()
-				if caller_element_id.is_none() {
+				} else {
-					metadata.upstream_footprints.entry(element_id).or_insert(footprint);
+					DAffine2::IDENTITY
-					metadata.local_transforms.entry(element_id).or_insert(item_zero_transform);
+				};
-				}
 
 				// Use click-target override if the item provides one (e.g. 'Text' node's per-glyph bboxes)
 				let click_target_vector = self.attribute::<Vector>(ATTR_EDITOR_CLICK_TARGET, index).unwrap_or(source);
 
-				let item_relative_transform = item_zero_inverse * transform;
+				let item_relative_transform = reference_inverse * transform;
 
 				let mut click_targets_unwrapped = Vec::new();
 				extend_targets_from_vector(&mut click_targets_unwrapped, self, index, click_target_vector, item_relative_transform);
@@ -1735,6 +1813,15 @@ impl Render for List<Vector> {
 		for (element_id, targets) in accumulated_outlines {
 			metadata.outlines.insert(element_id, targets);
 		}
+
+		// Recovering element_id from `editor:layer_path` means `Graphic::collect_metadata` skipped this transform metadata.
+		// It lands after the snapshot recursion above so each element keeps the pair its targets were baked against.
+		if caller_element_id.is_none() {
+			for (element_id, reference_transform) in reference_transforms {
+				metadata.upstream_footprints.insert(element_id, footprint);
+				metadata.local_transforms.insert(element_id, reference_transform);
+			}
+		}
 	}
 
 	fn add_upstream_click_targets(&self, click_targets: &mut Vec<ClickTarget>) {
@@ -1986,10 +2073,16 @@ impl Render for List<Raster<CPU>> {
 	}
 
 	fn add_upstream_click_targets(&self, click_targets: &mut Vec<ClickTarget>) {
-		let subpath = Subpath::new_rectangle(DVec2::ZERO, DVec2::ONE);
+		for index in 0..self.len() {
+			// The unit square is the raster's own space, so its placement only exists in the item transform
+			let transform: DAffine2 = self.attribute_cloned_or_default(ATTR_TRANSFORM, index);
+			let mut subpath = Subpath::new_rectangle(DVec2::ZERO, DVec2::ONE);
+			subpath.apply_transform(transform);
+
 			click_targets.push(ClickTarget::new_with_subpath(subpath, 0.));
 		}
 	}
+}
 
 static LAZY_ARC_VEC_ZERO_U8: LazyLock<Arc<Vec<u8>>> = LazyLock::new(|| Arc::new(Vec::new()));
 
@@ -2081,10 +2174,15 @@ impl Render for List<Raster<GPU>> {
 	}
 
 	fn add_upstream_click_targets(&self, click_targets: &mut Vec<ClickTarget>) {
-		let subpath = Subpath::new_rectangle(DVec2::ZERO, DVec2::ONE);
+		for index in 0..self.len() {
+			let transform: DAffine2 = self.attribute_cloned_or_default(ATTR_TRANSFORM, index);
+			let mut subpath = Subpath::new_rectangle(DVec2::ZERO, DVec2::ONE);
+			subpath.apply_transform(transform);
+
 			click_targets.push(ClickTarget::new_with_subpath(subpath, 0.));
 		}
 	}
+}
 
 // Since colors and gradients are technically infinitely big, we have to implement
 // workarounds for rendering them correctly in a way which still allows us

node-graph/nodes/graphic/src/graphic.rs

@@ -3,7 +3,7 @@ use core_types::list::{AttributeValueDyn, Item, List, ListDyn, NodeIdPath};
 use core_types::registry::types::{Angle, SeedValue, SignedInteger};
 use core_types::{ATTR_EDITOR_LAYER_PATH, ATTR_EDITOR_MERGED_LAYERS, ATTR_TRANSFORM, AnyHash, BlendMode, CacheHash, CloneVarArgs, Color, Context, Ctx, ExtractAll, OwnedContextImpl};
 use glam::{DAffine2, DVec2};
-use graphic_types::graphic::{Graphic, IntoGraphicList};
+use graphic_types::graphic::{Graphic, IntoGraphicList, is_lone_anonymous_leaf};
 use graphic_types::{Artboard, Vector};
 use rand::SeedableRng;
 use rand::seq::SliceRandom;
@@ -1020,7 +1020,7 @@ pub async fn flatten_vector<T: IntoGraphicList>(_: impl Ctx, #[implementations(L
 	// TODO: The cleaner fix is to drive each layer's metadata from its own Monitor's captured `(Context, List<Graphic>)`,
 	// TODO: at which point this attribute (and the equivalents in Boolean Operation, Solidify Stroke, Combine Paths,
 	// TODO: Morph, Rasterize) become unnecessary.
-	if !output.is_empty() {
+	if !output.is_empty() && !is_lone_anonymous_leaf(&graphic_list) {
 		// Item 0 carries a composed transform inherited from the flattened input, but the merged_layers
 		// already holds the original transforms; pre-compensate by item 0's inverse so the renderer's
 		// `upstream_footprint *= item_0_transform` recursion cancels out and leaves the originals intact.