Store an appearance's paint as a bare Graphic rather than a single-element List<Graphic>

editor/src/messages/portfolio/document/document_message_handler.rs

@@ -2760,9 +2760,7 @@ impl DocumentMessageHandler {
 			// A visible stroke needs both renderable geometry (non-zero weight) and paint that draws something
 			let has_stroke = appearance.is_some_and(|appearance| {
 				appearance.first_coverage_of(Cover::Stroke).is_some_and(|coverage| coverage.stroke_params().has_renderable_stroke())
-					&& appearance
-						.first_paint_of(Cover::Stroke)
-						.is_some_and(|paint| paint.element(0).is_some_and(|graphic| !graphic.is_fully_transparent()))
+					&& appearance.first_paint_of(Cover::Stroke).is_some_and(|paint| !paint.is_fully_transparent())
 			});
 
 			// No stroke means there's nothing to solidify. Fill-only layers are already in the desired form, so skip.

editor/src/messages/portfolio/document_migration.rs

@@ -10,7 +10,7 @@ use glam::{DVec2, IVec2};
 use graph_craft::application_io::resource::{DataSource, Resource, ResourceHash, ResourceId};
 use graph_craft::document::DocumentNode;
 use graph_craft::document::{DocumentNodeImplementation, NodeInput, value::TaggedValue};
-use graph_craft::{Type, item};
+use graph_craft::{Type, item, list};
 use graphene_std::Color;
 use graphene_std::ParameterRef;
 use graphene_std::ProtoNodeIdentifier;
@@ -1894,6 +1894,28 @@ fn migrate_node(node_id: &NodeId, node: &DocumentNode, network_path: &[NodeId],
 			.set_input(&InputConnector::node(*node_id, graphene_std::vector::stroke::DashPatternInput), migrated, network_path);
 	}
 
+	// The stored no-paint sentinel was the `List<Graphic>` type default before the paint connectors ranked down to `Item<Graphic>`.
+	// This must run before the stale-List-default cleanup below, which would otherwise adopt the definition's default paint.
+	{
+		let legacy_no_paint = TaggedValue::TypeDefault(list!(graphene_std::Graphic));
+		let paint_parameters: &[ParameterRef] = &[graphene_std::vector::fill::FillInput.into(), graphene_std::vector::stroke::PaintInput.into()];
+		for parameter in paint_parameters {
+			if reference != DefinitionIdentifier::ProtoNode(parameter.node_identifier.clone()) {
+				continue;
+			}
+			let Some(NodeInput::Value { tagged_value, exposed }) = node.inputs.get(parameter.input_index) else {
+				continue;
+			};
+			if **tagged_value == legacy_no_paint {
+				document.network_interface.set_input(
+					&InputConnector::node_at_index(*node_id, parameter.input_index),
+					NodeInput::value(TaggedValue::no_paint(), *exposed),
+					network_path,
+				);
+			}
+		}
+	}
+
 	// The corner radius became the `BoxCorners` value type; convert any already-shaped rectangle that still stores a legacy corner input
 	if reference == DefinitionIdentifier::ProtoNode(graphene_std::vector::generator_nodes::rectangle::IDENTIFIER)
 		&& let Some(corner_input) = node.input(graphene_std::vector::generator_nodes::rectangle::CornerRadiusInput)

node-graph/graph-craft/src/document/value.rs

@@ -707,14 +707,14 @@ impl TaggedValue {
 		}
 	}
 
-	/// The stored form of a paint input's red-slash "no paint" choice: the `List<Graphic>` type default, materializing as an empty paint list.
+	/// The stored form of a paint input's red-slash "no paint" choice: the `Item<Graphic>` type default, materializing as a `Graphic::None` paint.
 	pub fn no_paint() -> Self {
-		TaggedValue::TypeDefault(list!(Graphic))
+		TaggedValue::TypeDefault(item!(Graphic))
 	}
 
-	/// Whether this is the `List<Graphic>` type default created by [`Self::no_paint`] (and by disconnecting a paint wire).
+	/// Whether this is the `Item<Graphic>` type default created by [`Self::no_paint`] (and by disconnecting a paint wire).
 	pub fn is_no_paint(&self) -> bool {
-		matches!(self, TaggedValue::TypeDefault(td) if *td == list!(Graphic))
+		matches!(self, TaggedValue::TypeDefault(td) if *td == item!(Graphic))
 	}
 }
 

node-graph/libraries/core-types/src/list.rs

@@ -80,7 +80,7 @@ pub const ATTR_MIDPOINT: &str = "midpoint";
 /// Item's ordered list of paint passes, of type `Appearance`. Earlier coverages paint first, compositing below later ones.
 pub const ATTR_APPEARANCE: &str = "appearance";
 // TODO: Add a "fill_rule" attribute as a sibling of "paint" on the coverage list (uniform across covers) once a FillRule type ships
-/// Coverage's `List<Graphic>` paint (implicit default empty, painting nothing), on the
+/// Coverage's `Graphic` paint (implicit default `Graphic::None`, painting nothing), on the
 /// `List<Coverage>` inside an `Appearance`.
 pub const ATTR_PAINT: &str = "paint";
 /// Stroke coverage's line thickness (`f64`, implicit default `0.`), on the `Item<Cover>` inside a `Coverage`.

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

@@ -2,10 +2,13 @@
 //! Data uniform across all covers (the paint) rides the outer `List<Coverage>` so columnar presence holds,
 //! while cover-specific data rides the inner `Item<Cover>`, reusing `ATTR_TRANSFORM` for the stroke-authoring space.
 
-use crate::graphic::{Graphic, is_paint_present};
+use crate::graphic::Graphic;
+use core_types::Color;
 use core_types::graphene_hash::CacheHash;
 use core_types::list::{ATTR_ALIGN, ATTR_APPEARANCE, ATTR_CAP, ATTR_DASH_OFFSET, ATTR_DASH_PATTERN, ATTR_JOIN, ATTR_JOIN_MITER_LIMIT, ATTR_PAINT, ATTR_TRANSFORM, ATTR_WEIGHT, Item, List};
+use raster_types::{CPU, GPU, Raster};
 use vector_types::vector::style::{DashPattern, Stroke};
+use vector_types::{Gradient, Vector};
 
 /// The geometry-to-region operator a coverage applies before painting:
 /// the interior of the geometry (fill) or the region swept along its outline (stroke).
@@ -114,18 +117,18 @@ impl Coverage {
 	}
 }
 
-/// Builds an appearance row, eliding the paint attribute when it draws nothing.
-fn cover_row(coverage: Coverage, paint: List<Graphic>) -> Item<Coverage> {
+/// Builds an appearance row, eliding the paint attribute when it is the default none-paint.
+fn cover_row(coverage: Coverage, paint: Graphic) -> Item<Coverage> {
 	let mut row = Item::new_from_element(coverage);
-	if is_paint_present(&paint) {
+	if paint != Graphic::default() {
 		row.set_attribute(ATTR_PAINT, paint);
 	}
 	row
 }
 
 impl Appearance {
 	/// Creates an appearance holding a single coverage with the given paint.
-	pub fn new_single(coverage: Coverage, paint: List<Graphic>) -> Self {
+	pub fn new_single(coverage: Coverage, paint: Graphic) -> Self {
 		Self(List::new_from_item(cover_row(coverage, paint)))
 	}
 
@@ -161,8 +164,8 @@ impl Appearance {
 	}
 
 	/// The paint of the coverage at the given index, or `None` if the paint attribute is absent.
-	pub fn paint_at(&self, index: usize) -> Option<&List<Graphic>> {
-		self.0.attribute::<List<Graphic>>(ATTR_PAINT, index)
+	pub fn paint_at(&self, index: usize) -> Option<&Graphic> {
+		self.0.attribute::<Graphic>(ATTR_PAINT, index)
 	}
 
 	/// The index of the first coverage of the given cover in paint order.
@@ -176,15 +179,13 @@ impl Appearance {
 	}
 
 	/// The paint of the first coverage of the given cover, filtered to paint that draws something.
-	pub fn first_paint_of(&self, cover: Cover) -> Option<&List<Graphic>> {
-		self.first_index_of(cover).and_then(|index| self.paint_at(index)).filter(|paint| is_paint_present(paint))
+	pub fn first_paint_of(&self, cover: Cover) -> Option<&Graphic> {
+		self.first_index_of(cover).and_then(|index| self.paint_at(index)).filter(|paint| !paint.is_empty())
 	}
 
 	/// Iterates the coverages in paint order together with their paint, which is `None` when absent or drawing nothing.
-	pub fn covers_with_paints(&self) -> impl Iterator<Item = (&Coverage, Option<&List<Graphic>>)> {
-		self.covers()
-			.enumerate()
-			.map(|(index, coverage)| (coverage, self.paint_at(index).filter(|paint| is_paint_present(paint))))
+	pub fn covers_with_paints(&self) -> impl Iterator<Item = (&Coverage, Option<&Graphic>)> {
+		self.covers().enumerate().map(|(index, coverage)| (coverage, self.paint_at(index).filter(|paint| !paint.is_empty())))
 	}
 
 	/// Gathers the renderer's per-item reads in one walk of the coverage list.
@@ -199,7 +200,7 @@ impl Appearance {
 			}
 		}
 
-		let painted = |index| self.paint_at(index).filter(|paint| is_paint_present(paint));
+		let painted = |index| self.paint_at(index).filter(|paint| !paint.is_empty());
 		FillAndStroke {
 			stroke: first_stroke.map(|(_, coverage)| coverage.stroke_params()),
 			fill_paint: first_fill.and_then(painted),
@@ -218,12 +219,12 @@ impl Appearance {
 	pub fn has_painted_cover(&self, cover: Cover) -> bool {
 		self.covers()
 			.enumerate()
-			.any(|(index, coverage)| coverage.cover() == cover && self.paint_at(index).is_some_and(is_paint_present))
+			.any(|(index, coverage)| coverage.cover() == cover && self.paint_at(index).is_some_and(|paint| !paint.is_empty()))
 	}
 
 	/// Replaces the first coverage of the incoming cover in place (keeping its position in the paint order),
 	/// or inserts a new row at the requested end of the paint order if none exists.
-	pub fn replace_or_insert(&mut self, coverage: Coverage, paint: List<Graphic>, placement: CoverPlacement) {
+	pub fn replace_or_insert(&mut self, coverage: Coverage, paint: Graphic, placement: CoverPlacement) {
 		if let Some(index) = self.first_index_of(coverage.cover()) {
 			if let Some(element) = self.0.element_mut(index) {
 				*element = coverage;
@@ -245,7 +246,7 @@ impl Appearance {
 
 	/// Sets the paint of the first coverage of the given cover, leaving its other parameters untouched.
 	/// Returns `false` without changing anything if no coverage of that cover exists.
-	pub fn set_paint_of(&mut self, cover: Cover, paint: List<Graphic>) -> bool {
+	pub fn set_paint_of(&mut self, cover: Cover, paint: Graphic) -> bool {
 		let Some(index) = self.first_index_of(cover) else { return false };
 		self.0.set_attribute(ATTR_PAINT, index, paint);
 		true
@@ -262,32 +263,117 @@ impl Appearance {
 #[derive(Debug, Default)]
 pub struct FillAndStroke<'a> {
 	pub stroke: Option<Stroke>,
-	pub fill_paint: Option<&'a List<Graphic>>,
-	pub stroke_paint: Option<&'a List<Graphic>>,
+	pub fill_paint: Option<&'a Graphic>,
+	pub stroke_paint: Option<&'a Graphic>,
 	/// Whether the first stroke coverage sits before the first fill in the paint order, painting below it.
 	pub stroke_below: bool,
 }
 
 /// Stamps a coverage into the item's `ATTR_APPEARANCE` cell, creating the attribute if absent.
 /// The coverage replaces the first same-cover one in place, or lands at the placement end of the paint order.
-pub fn stamp_coverage<T>(item: &mut Item<T>, coverage: Coverage, paint: List<Graphic>, placement: CoverPlacement) {
+pub fn stamp_coverage<T>(item: &mut Item<T>, coverage: Coverage, paint: Graphic, placement: CoverPlacement) {
 	item.attribute_mut_or_insert_default::<Appearance>(ATTR_APPEARANCE).replace_or_insert(coverage, paint, placement);
 }
 
+// ================
+// TRAIT: IntoPaint
+// ================
+
+/// Converts the types accepted by a paint input into the canonical `Graphic` stored in the `ATTR_PAINT` attribute.
+/// `List<Graphic>` deliberately has no impl: a multi-element paint is a type error.
+pub trait IntoPaint: Clone + Send + Sync + Default + std::fmt::Debug + PartialEq + CacheHash + 'static {
+	fn into_paint(self) -> Graphic;
+}
+
+impl IntoPaint for Item<Graphic> {
+	fn into_paint(self) -> Graphic {
+		// Wrapping to keep the record's attributes would nest the paint as a group, changing how it renders
+		self.into_element()
+	}
+}
+
+impl IntoPaint for Item<Vector> {
+	fn into_paint(self) -> Graphic {
+		Graphic::VectorList(List::new_from_item(self))
+	}
+}
+
+impl IntoPaint for Item<Raster<CPU>> {
+	fn into_paint(self) -> Graphic {
+		Graphic::RasterCPUList(List::new_from_item(self))
+	}
+}
+
+// No Item<Raster<GPU>> impl: GPU rasters have no Default, which the trait bounds require of the element
+
+impl IntoPaint for Item<Color> {
+	fn into_paint(self) -> Graphic {
+		Graphic::ColorList(List::new_from_item(self))
+	}
+}
+
+impl IntoPaint for Item<Gradient> {
+	fn into_paint(self) -> Graphic {
+		Graphic::GradientList(List::new_from_item(self))
+	}
+}
+
+impl IntoPaint for Item<String> {
+	fn into_paint(self) -> Graphic {
+		Graphic::TextList(List::new_from_item(self))
+	}
+}
+
+impl IntoPaint for List<Vector> {
+	fn into_paint(self) -> Graphic {
+		Graphic::VectorList(self)
+	}
+}
+
+impl IntoPaint for List<Raster<CPU>> {
+	fn into_paint(self) -> Graphic {
+		Graphic::RasterCPUList(self)
+	}
+}
+
+impl IntoPaint for List<Raster<GPU>> {
+	fn into_paint(self) -> Graphic {
+		Graphic::RasterGPUList(self)
+	}
+}
+
+impl IntoPaint for List<Color> {
+	fn into_paint(self) -> Graphic {
+		Graphic::ColorList(self)
+	}
+}
+
+impl IntoPaint for List<Gradient> {
+	fn into_paint(self) -> Graphic {
+		Graphic::GradientList(self)
+	}
+}
+
+impl IntoPaint for List<String> {
+	fn into_paint(self) -> Graphic {
+		Graphic::TextList(self)
+	}
+}
+
 #[cfg(test)]
 mod tests {
 	use super::*;
-	use core_types::Color;
+	use core_types::list::ATTR_POSITION;
 	use glam::{DAffine2, DVec2};
 	use vector_types::vector::style::{StrokeAlign, StrokeCap, StrokeJoin};
 
-	fn solid_paint(color: Color) -> List<Graphic> {
-		List::new_from_element(Graphic::ColorList(List::new_from_element(color)))
+	fn solid_paint(color: Color) -> Graphic {
+		Graphic::ColorList(List::new_from_element(color))
 	}
 
 	fn paint_color(appearance: &Appearance, index: usize) -> Option<Color> {
 		let paint = appearance.paint_at(index)?;
-		let Some(Graphic::ColorList(colors)) = paint.element(0) else { return None };
+		let Graphic::ColorList(colors) = paint else { return None };
 		colors.element(0).copied()
 	}
 
@@ -374,7 +460,7 @@ mod tests {
 	#[test]
 	fn painted_cover_distinguishes_none_paint_from_absence() {
 		let mut appearance = Appearance::default();
-		appearance.replace_or_insert(Coverage::new_fill(), List::new_from_element(Graphic::None), CoverPlacement::Above);
+		appearance.replace_or_insert(Coverage::new_fill(), Graphic::None, CoverPlacement::Above);
 
 		assert!(appearance.has_cover(Cover::Fill), "a none-painted coverage still exists");
 		assert!(!appearance.has_painted_cover(Cover::Fill), "a none-painted coverage draws nothing");
@@ -384,4 +470,24 @@ mod tests {
 		appearance.replace_or_insert(Coverage::new_fill(), solid_paint(Color::RED), CoverPlacement::Above);
 		assert!(appearance.has_painted_cover(Cover::Fill));
 	}
+
+	#[test]
+	fn list_paint_becomes_one_graphic_holding_every_element() {
+		let mut colors = List::new_from_element(Color::RED);
+		colors.push(Item::new_from_element(Color::BLUE));
+
+		let paint = colors.into_paint();
+		let Graphic::ColorList(inner) = &paint else { panic!("expected a color graphic") };
+		assert_eq!(inner.len(), 2, "a list paint is one graphic holding all its elements");
+	}
+
+	#[test]
+	fn item_paint_keeps_its_attributes_on_the_inner_row() {
+		let color = Item::new_from_element(Color::RED).with_attribute(ATTR_POSITION, 0.25_f64);
+
+		let paint = color.into_paint();
+		let Graphic::ColorList(inner) = &paint else { panic!("expected a color graphic") };
+		assert_eq!(inner.len(), 1);
+		assert_eq!(inner.attribute::<f64>(ATTR_POSITION, 0), Some(&0.25));
+	}
 }