Improve the Gradient tool by visualizing color stops (#3698)

* Gradient

* improvement

* removed unnecessary code

* corrected error

* Partical changes

* Improveded

* remove from advertised actions

* Mousedown

* Partial code review

* changes as per recommendation

* corrected error

* corrected error -2

* changes as per recommendation

* error corrected

* changes as suggested

* Bug Fix

* Fix hints

---------

Co-authored-by: Keavon Chambers <keavon@keavon.com>

editor/src/consts.rs

@@ -153,6 +153,7 @@ pub const COLOR_OVERLAY_RED: &str = "#ef5454";
 pub const COLOR_OVERLAY_GRAY: &str = "#cccccc";
 pub const COLOR_OVERLAY_GRAY_25: &str = "#cccccc40";
 pub const COLOR_OVERLAY_WHITE: &str = "#ffffff";
+pub const COLOR_OVERLAY_BLACK: &str = "#000000";
 pub const COLOR_OVERLAY_BLACK_75: &str = "#000000bf";
 
 // DOCUMENT

editor/src/messages/input_mapper/input_mappings.rs

@@ -178,7 +178,6 @@ pub fn input_mappings(zoom_with_scroll: bool) -> Mapping {
 		entry!(KeyDown(MouseLeft); action_dispatch=GradientToolMessage::PointerDown),
 		entry!(PointerMove; refresh_keys=[Shift], action_dispatch=GradientToolMessage::PointerMove { constrain_axis: Shift }),
 		entry!(KeyUp(MouseLeft); action_dispatch=GradientToolMessage::PointerUp),
-		entry!(DoubleClick(MouseButton::Left); action_dispatch=GradientToolMessage::InsertStop),
 		entry!(KeyDown(Delete); action_dispatch=GradientToolMessage::DeleteStop),
 		entry!(KeyDown(Backspace); action_dispatch=GradientToolMessage::DeleteStop),
 		entry!(KeyDown(MouseRight); action_dispatch=GradientToolMessage::Abort),

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

@@ -964,6 +964,7 @@ impl MessageHandler<DocumentMessage, DocumentMessageContext<'_>> for DocumentMes
 				responses.add(DocumentMessage::DocumentHistoryForward);
 				responses.add(ToolMessage::Redo);
 				responses.add(OverlaysMessage::Draw);
+				responses.add(EventMessage::SelectionChanged);
 			}
 			DocumentMessage::RenameDocument { new_name } => {
 				self.name = new_name.clone();
@@ -1431,6 +1432,7 @@ impl MessageHandler<DocumentMessage, DocumentMessageContext<'_>> for DocumentMes
 				responses.add(DocumentMessage::DocumentHistoryBackward);
 				responses.add(OverlaysMessage::Draw);
 				responses.add(ToolMessage::Undo);
+				responses.add(EventMessage::SelectionChanged);
 			}
 			DocumentMessage::UngroupSelectedLayers => {
 				if !self.selection_network_path.is_empty() {

editor/src/messages/portfolio/document/node_graph/node_graph_message_handler.rs

@@ -25,6 +25,7 @@ use crate::messages::tool::tool_messages::tool_prelude::{Key, MouseMotion};
 use crate::messages::tool::utility_types::{HintData, HintGroup, HintInfo};
 use crate::messages::viewport::Position;
 use glam::{DAffine2, DVec2, IVec2};
+use graph_craft::document::value::TaggedValue;
 use graph_craft::document::{DocumentNodeImplementation, NodeId, NodeInput};
 use graphene_std::math::math_ext::QuadExt;
 use graphene_std::vector::algorithms::bezpath_algorithms::bezpath_is_inside_bezpath;
@@ -1699,12 +1700,16 @@ impl<'a> MessageHandler<NodeGraphMessage, NodeGraphMessageContext<'a>> for NodeG
 				}
 			}
 			NodeGraphMessage::SetInputValue { node_id, input_index, value } => {
+				let is_fill = matches!(value, TaggedValue::Fill(_));
 				let input = NodeInput::value(value, false);
 				responses.add(NodeGraphMessage::SetInput {
 					input_connector: InputConnector::node(node_id, input_index),
 					input,
 				});
 				responses.add(PropertiesPanelMessage::Refresh);
+				if is_fill {
+					responses.add(OverlaysMessage::Draw);
+				}
 				if network_interface.connected_to_output(&node_id, selection_network_path) {
 					responses.add(NodeGraphMessage::RunDocumentGraph);
 				}

editor/src/messages/portfolio/document/overlays/utility_types_native.rs

@@ -1,7 +1,7 @@
 use crate::consts::{
-	ARC_SWEEP_GIZMO_RADIUS, COLOR_OVERLAY_BLUE, COLOR_OVERLAY_BLUE_50, COLOR_OVERLAY_GREEN, COLOR_OVERLAY_RED, COLOR_OVERLAY_WHITE, COLOR_OVERLAY_YELLOW, COLOR_OVERLAY_YELLOW_DULL,
+	ARC_SWEEP_GIZMO_RADIUS, COLOR_OVERLAY_BLACK, COLOR_OVERLAY_BLUE, COLOR_OVERLAY_BLUE_50, COLOR_OVERLAY_GREEN, COLOR_OVERLAY_RED, COLOR_OVERLAY_WHITE, COLOR_OVERLAY_YELLOW,
-	COMPASS_ROSE_ARROW_SIZE, COMPASS_ROSE_HOVER_RING_DIAMETER, COMPASS_ROSE_MAIN_RING_DIAMETER, COMPASS_ROSE_RING_INNER_DIAMETER, DOWEL_PIN_RADIUS, MANIPULATOR_GROUP_MARKER_SIZE,
+	COLOR_OVERLAY_YELLOW_DULL, COMPASS_ROSE_ARROW_SIZE, COMPASS_ROSE_HOVER_RING_DIAMETER, COMPASS_ROSE_MAIN_RING_DIAMETER, COMPASS_ROSE_RING_INNER_DIAMETER, DOWEL_PIN_RADIUS,
-	PIVOT_CROSSHAIR_LENGTH, PIVOT_CROSSHAIR_THICKNESS, PIVOT_DIAMETER, RESIZE_HANDLE_SIZE, SKEW_TRIANGLE_OFFSET, SKEW_TRIANGLE_SIZE,
+	MANIPULATOR_GROUP_MARKER_SIZE, PIVOT_CROSSHAIR_LENGTH, PIVOT_CROSSHAIR_THICKNESS, PIVOT_DIAMETER, RESIZE_HANDLE_SIZE, SKEW_TRIANGLE_OFFSET, SKEW_TRIANGLE_SIZE,
 };
 use crate::messages::portfolio::document::overlays::utility_functions::{GLOBAL_FONT_CACHE, GLOBAL_TEXT_CONTEXT};
 use crate::messages::portfolio::document::utility_types::document_metadata::LayerNodeIdentifier;
@@ -273,6 +273,10 @@ impl OverlayContext {
 		self.internal().manipulator_anchor(position, selected, color);
 	}
 
+	pub fn gradient_color_stop(&mut self, position: DVec2, selected: bool, color: &str) {
+		self.internal().gradient_color_stop(position, selected, color);
+	}
+
 	pub fn resize_handle(&mut self, position: DVec2, rotation: f64) {
 		self.internal().resize_handle(position, rotation);
 	}
@@ -583,6 +587,29 @@ impl OverlayContextInternal {
 		self.square(position, None, Some(color_fill), Some(COLOR_OVERLAY_BLUE));
 	}
 
+	fn gradient_color_stop(&mut self, position: DVec2, selected: bool, color: &str) {
+		let transform = self.get_transform();
+		let position = position.round() - DVec2::splat(0.5);
+
+		let (radius_offset, stroke_width) = if selected { (1., 3.) } else { (0., 1.) };
+		let radius = MANIPULATOR_GROUP_MARKER_SIZE / 1.5 + 1. + radius_offset;
+
+		let mut draw_circle = |radius: f64, width: Option<f64>, color: &str| {
+			let circle = kurbo::Circle::new((position.x, position.y), radius);
+			if let Some(width) = width {
+				self.scene.stroke(&kurbo::Stroke::new(width), transform, Self::parse_color(color), None, &circle);
+			} else {
+				self.scene.fill(peniko::Fill::NonZero, transform, Self::parse_color(color), None, &circle);
+			}
+		};
+		// Fill
+		draw_circle(radius, None, color);
+		// Stroke (inner)
+		draw_circle(radius + stroke_width / 2., Some(1.), COLOR_OVERLAY_BLACK);
+		// Stroke (outer)
+		draw_circle(radius, Some(stroke_width), COLOR_OVERLAY_WHITE);
+	}
+
 	fn resize_handle(&mut self, position: DVec2, rotation: f64) {
 		let quad = DAffine2::from_angle_translation(rotation, position) * Quad::from_box([DVec2::splat(-RESIZE_HANDLE_SIZE / 2.), DVec2::splat(RESIZE_HANDLE_SIZE / 2.)]);
 		self.quad(quad, None, Some(COLOR_OVERLAY_WHITE));
@@ -832,7 +859,7 @@ impl OverlayContextInternal {
 		path.move_to(kurbo::Point::new(x, y));
 		path.line_to(kurbo::Point::new(start1_x, start1_y));
 
-		let arc1 = kurbo::Arc::new((x, y), (DOWEL_PIN_RADIUS, DOWEL_PIN_RADIUS), start1, FRAC_PI_2, 0.0);
+		let arc1 = kurbo::Arc::new((x, y), (DOWEL_PIN_RADIUS, DOWEL_PIN_RADIUS), start1, FRAC_PI_2, 0.);
 		arc1.to_cubic_beziers(0.1, |p1, p2, p| {
 			path.curve_to(p1, p2, p);
 		});
@@ -844,7 +871,7 @@ impl OverlayContextInternal {
 		path.move_to(kurbo::Point::new(x, y));
 		path.line_to(kurbo::Point::new(start2_x, start2_y));
 
-		let arc2 = kurbo::Arc::new((x, y), (DOWEL_PIN_RADIUS, DOWEL_PIN_RADIUS), start2, FRAC_PI_2, 0.0);
+		let arc2 = kurbo::Arc::new((x, y), (DOWEL_PIN_RADIUS, DOWEL_PIN_RADIUS), start2, FRAC_PI_2, 0.);
 		arc2.to_cubic_beziers(0.1, |p1, p2, p| {
 			path.curve_to(p1, p2, p);
 		});
@@ -891,7 +918,7 @@ impl OverlayContextInternal {
 		let mut path = BezPath::new();
 		self.bezier_to_path(bezier, transform, true, &mut path);
 
-		self.scene.stroke(&kurbo::Stroke::new(4.0), vello_transform, Self::parse_color(COLOR_OVERLAY_BLUE), None, &path);
+		self.scene.stroke(&kurbo::Stroke::new(4.), vello_transform, Self::parse_color(COLOR_OVERLAY_BLUE), None, &path);
 	}
 
 	fn outline_overlay_bezier(&mut self, bezier: PathSeg, transform: DAffine2) {
@@ -899,7 +926,7 @@ impl OverlayContextInternal {
 		let mut path = BezPath::new();
 		self.bezier_to_path(bezier, transform, true, &mut path);
 
-		self.scene.stroke(&kurbo::Stroke::new(4.0), vello_transform, Self::parse_color(COLOR_OVERLAY_BLUE_50), None, &path);
+		self.scene.stroke(&kurbo::Stroke::new(4.), vello_transform, Self::parse_color(COLOR_OVERLAY_BLUE_50), None, &path);
 	}
 
 	fn bezier_to_path(&self, bezier: PathSeg, transform: DAffine2, move_to: bool, path: &mut BezPath) {
@@ -1035,16 +1062,16 @@ impl OverlayContextInternal {
 
 	fn text(&mut self, text: &str, font_color: &str, background_color: Option<&str>, transform: DAffine2, padding: f64, pivot: [Pivot; 2]) {
 		// Use the proper text-to-path system for accurate text rendering
-		const FONT_SIZE: f64 = 12.0;
+		const FONT_SIZE: f64 = 12.;
 
 		// Create typesetting configuration
 		let typesetting = TypesettingConfig {
 			font_size: FONT_SIZE,
 			line_height_ratio: 1.2,
-			character_spacing: 0.0,
+			character_spacing: 0.,
 			max_width: None,
 			max_height: None,
-			tilt: 0.0,
+			tilt: 0.,
 			align: TextAlign::Left, // We'll handle alignment manually via pivot
 		};
 
@@ -1059,7 +1086,7 @@ impl OverlayContextInternal {
 		let text_width = text_size.x;
 		let text_height = text_size.y;
 		// Create a rect from the size (assuming text starts at origin)
-		let text_bounds = kurbo::Rect::new(0.0, 0.0, text_width, text_height);
+		let text_bounds = kurbo::Rect::new(0., 0., text_width, text_height);
 
 		// Convert text to vector paths for rendering
 		let text_table = text_context.to_path(text, &font, &GLOBAL_FONT_CACHE, typesetting, false);
@@ -1068,7 +1095,7 @@ impl OverlayContextInternal {
 		let mut position = DVec2::ZERO;
 		match pivot[0] {
 			Pivot::Start => position.x = padding,
-			Pivot::Middle => position.x = -text_width / 2.0,
+			Pivot::Middle => position.x = -text_width / 2.,
 			Pivot::End => position.x = -padding - text_width,
 		}
 		match pivot[1] {

editor/src/messages/portfolio/document/overlays/utility_types_web.rs

@@ -1,8 +1,8 @@
 use super::utility_functions::overlay_canvas_context;
 use crate::consts::{
-	ARC_SWEEP_GIZMO_RADIUS, COLOR_OVERLAY_BLUE, COLOR_OVERLAY_BLUE_50, COLOR_OVERLAY_GREEN, COLOR_OVERLAY_RED, COLOR_OVERLAY_WHITE, COLOR_OVERLAY_YELLOW, COLOR_OVERLAY_YELLOW_DULL,
+	ARC_SWEEP_GIZMO_RADIUS, COLOR_OVERLAY_BLACK, COLOR_OVERLAY_BLUE, COLOR_OVERLAY_BLUE_50, COLOR_OVERLAY_GREEN, COLOR_OVERLAY_RED, COLOR_OVERLAY_WHITE, COLOR_OVERLAY_YELLOW,
-	COMPASS_ROSE_ARROW_SIZE, COMPASS_ROSE_HOVER_RING_DIAMETER, COMPASS_ROSE_MAIN_RING_DIAMETER, COMPASS_ROSE_RING_INNER_DIAMETER, DOWEL_PIN_RADIUS, MANIPULATOR_GROUP_MARKER_SIZE,
+	COLOR_OVERLAY_YELLOW_DULL, COMPASS_ROSE_ARROW_SIZE, COMPASS_ROSE_HOVER_RING_DIAMETER, COMPASS_ROSE_MAIN_RING_DIAMETER, COMPASS_ROSE_RING_INNER_DIAMETER, DOWEL_PIN_RADIUS,
-	PIVOT_CROSSHAIR_LENGTH, PIVOT_CROSSHAIR_THICKNESS, PIVOT_DIAMETER, RESIZE_HANDLE_SIZE, SEGMENT_SELECTED_THICKNESS, SKEW_TRIANGLE_OFFSET, SKEW_TRIANGLE_SIZE,
+	MANIPULATOR_GROUP_MARKER_SIZE, PIVOT_CROSSHAIR_LENGTH, PIVOT_CROSSHAIR_THICKNESS, PIVOT_DIAMETER, RESIZE_HANDLE_SIZE, SEGMENT_SELECTED_THICKNESS, SKEW_TRIANGLE_OFFSET, SKEW_TRIANGLE_SIZE,
 };
 use crate::messages::portfolio::document::utility_types::document_metadata::LayerNodeIdentifier;
 use crate::messages::prelude::Message;
@@ -468,6 +468,37 @@ impl OverlayContext {
 		self.square(position, None, Some(color_fill), Some(color_stroke));
 	}
 
+	pub fn gradient_color_stop(&mut self, position: DVec2, selected: bool, color: &str) {
+		self.start_dpi_aware_transform();
+
+		let position = position.round() - DVec2::splat(0.5);
+
+		let (radius_offset, stroke_width) = if selected { (1., 3.) } else { (0., 1.) };
+		let radius = MANIPULATOR_GROUP_MARKER_SIZE / 1.5 + 1. + radius_offset;
+
+		let draw_circle = |radius: f64, width: Option<f64>, color: &str| {
+			self.render_context.begin_path();
+			self.render_context.arc(position.x, position.y, radius, 0., TAU).expect("Failed to draw the circle");
+
+			if let Some(width) = width {
+				self.render_context.set_line_width(width);
+				self.render_context.set_stroke_style_str(color);
+				self.render_context.stroke();
+			} else {
+				self.render_context.set_fill_style_str(color);
+				self.render_context.fill();
+			}
+		};
+		// Fill
+		draw_circle(radius, None, color);
+		// Stroke (inner)
+		draw_circle(radius + stroke_width / 2., Some(1.), COLOR_OVERLAY_BLACK);
+		// Stroke (outer)
+		draw_circle(radius, Some(stroke_width), COLOR_OVERLAY_WHITE);
+
+		self.end_dpi_aware_transform();
+	}
+
 	pub fn hover_manipulator_handle(&mut self, position: DVec2, selected: bool) {
 		self.start_dpi_aware_transform();
 

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

@@ -1,5 +1,5 @@
 use super::tool_prelude::*;
-use crate::consts::{LINE_ROTATE_SNAP_ANGLE, MANIPULATOR_GROUP_MARKER_SIZE, SELECTION_THRESHOLD};
+use crate::consts::{COLOR_OVERLAY_BLUE, DRAG_THRESHOLD, LINE_ROTATE_SNAP_ANGLE, MANIPULATOR_GROUP_MARKER_SIZE, SEGMENT_INSERTION_DISTANCE, SEGMENT_OVERLAY_SIZE, SELECTION_THRESHOLD};
 use crate::messages::portfolio::document::overlays::utility_types::OverlayContext;
 use crate::messages::portfolio::document::utility_types::document_metadata::LayerNodeIdentifier;
 use crate::messages::tool::common_functionality::auto_panning::AutoPanning;
@@ -25,6 +25,7 @@ pub enum GradientToolMessage {
 	// Standard messages
 	Abort,
 	Overlays { context: OverlayContext },
+	SelectionChanged,
 
 	// Tool-specific messages
 	DeleteStop,
@@ -76,30 +77,29 @@ impl<'a> MessageHandler<ToolMessage, &mut ToolActionMessageContext<'a>> for Grad
 						continue;
 					}
 
-					if let Some(mut gradient) = get_gradient(layer, &context.document.network_interface) {
+					if let Some(mut gradient) = get_gradient(layer, &context.document.network_interface)
-						if gradient.gradient_type != gradient_type {
+						&& gradient.gradient_type != gradient_type
-							if !transaction_started {
+					{
-								responses.add(DocumentMessage::StartTransaction);
+						if !transaction_started {
-								transaction_started = true;
+							responses.add(DocumentMessage::StartTransaction);
-							}
+							transaction_started = true;
-							gradient.gradient_type = gradient_type;
-							responses.add(GraphOperationMessage::FillSet {
-								layer,
-								fill: Fill::Gradient(gradient),
-							});
 						}
+						gradient.gradient_type = gradient_type;
+						responses.add(GraphOperationMessage::FillSet {
+							layer,
+							fill: Fill::Gradient(gradient),
+						});
 					}
 				}
 
 				if transaction_started {
 					responses.add(DocumentMessage::AddTransaction);
 				}
-				if let Some(selected_gradient) = &mut self.data.selected_gradient {
+				if let Some(selected_gradient) = &mut self.data.selected_gradient
-					if let Some(layer) = selected_gradient.layer {
+					&& let Some(layer) = selected_gradient.layer
-						if !NodeGraphLayer::is_raster_layer(layer, &mut context.document.network_interface) {
+					&& !NodeGraphLayer::is_raster_layer(layer, &mut context.document.network_interface)
-							selected_gradient.gradient.gradient_type = gradient_type;
+				{
-						}
+					selected_gradient.gradient.gradient_type = gradient_type;
-					}
 				}
 				responses.add(ToolMessage::UpdateHints);
 				responses.add(PropertiesPanelMessage::Refresh);
@@ -114,7 +114,6 @@ impl<'a> MessageHandler<ToolMessage, &mut ToolActionMessageContext<'a>> for Grad
 		PointerUp,
 		PointerMove,
 		Abort,
-		InsertStop,
 		DeleteStop,
 	);
 }
@@ -142,13 +141,18 @@ impl LayoutHolder for GradientTool {
 	}
 }
 
-#[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
 enum GradientToolFsmState {
-	#[default]
+	Ready { hover_insertion: bool },
-	Ready,
 	Drawing,
 }
 
+impl Default for GradientToolFsmState {
+	fn default() -> Self {
+		Self::Ready { hover_insertion: false }
+	}
+}
+
 /// Computes the transform from gradient space to viewport space (where gradient space is 0..1)
 fn gradient_space_transform(layer: LayerNodeIdentifier, document: &DocumentMessageHandler) -> DAffine2 {
 	let bounds = document.metadata().nonzero_bounding_box(layer);
@@ -165,6 +169,7 @@ pub enum GradientDragTarget {
 	#[default]
 	End,
 	Step(usize),
+	New,
 }
 
 /// Contains information about the selected gradient handle
@@ -174,6 +179,28 @@ struct SelectedGradient {
 	transform: DAffine2,
 	gradient: Gradient,
 	dragging: GradientDragTarget,
+	initial_gradient: Gradient,
+}
+
+fn calculate_insertion(start: DVec2, end: DVec2, stops: &[(f64, graphene_std::Color)], mouse: DVec2) -> Option<f64> {
+	let distance = (end - start).angle_to(mouse - start).sin() * (mouse - start).length();
+	let projection = ((end - start).angle_to(mouse - start)).cos() * start.distance(mouse) / start.distance(end);
+
+	if distance.abs() < SEGMENT_INSERTION_DISTANCE && (0. ..=1.).contains(&projection) {
+		for (position, _) in stops {
+			let stop_pos = start.lerp(end, *position);
+			if stop_pos.distance_squared(mouse) < (MANIPULATOR_GROUP_MARKER_SIZE * 2.).powi(2) {
+				return None;
+			}
+		}
+		if start.distance_squared(mouse) < (MANIPULATOR_GROUP_MARKER_SIZE * 2.).powi(2) || end.distance_squared(mouse) < (MANIPULATOR_GROUP_MARKER_SIZE * 2.).powi(2) {
+			return None;
+		}
+
+		return Some(projection);
+	}
+
+	None
 }
 
 impl SelectedGradient {
@@ -182,22 +209,26 @@ impl SelectedGradient {
 		Self {
 			layer: Some(layer),
 			transform,
-			gradient,
+			gradient: gradient.clone(),
 			dragging: GradientDragTarget::End,
+			initial_gradient: gradient,
 		}
 	}
 
-	pub fn with_gradient_start(mut self, start: DVec2) -> Self {
+	pub fn update_gradient(&mut self, mut mouse: DVec2, responses: &mut VecDeque<Message>, snap_rotate: bool, gradient_type: GradientType, drag_start: DVec2) {
-		self.gradient.start = self.transform.inverse().transform_point2(start);
+		if mouse.distance(drag_start) < DRAG_THRESHOLD {
-		self
+			self.gradient = self.initial_gradient.clone();
-	}
+			self.render_gradient(responses);
+			return;
+		}
 
-	pub fn update_gradient(&mut self, mut mouse: DVec2, responses: &mut VecDeque<Message>, snap_rotate: bool, gradient_type: GradientType) {
 		self.gradient.gradient_type = gradient_type;
 
-		if snap_rotate && matches!(self.dragging, GradientDragTarget::End | GradientDragTarget::Start) {
+		if snap_rotate && matches!(self.dragging, GradientDragTarget::End | GradientDragTarget::Start | GradientDragTarget::New) {
 			let point = if self.dragging == GradientDragTarget::Start {
 				self.transform.transform_point2(self.gradient.end)
+			} else if self.dragging == GradientDragTarget::New {
+				drag_start
 			} else {
 				self.transform.transform_point2(self.gradient.start)
 			};
@@ -219,6 +250,10 @@ impl SelectedGradient {
 		match self.dragging {
 			GradientDragTarget::Start => self.gradient.start = transformed_mouse,
 			GradientDragTarget::End => self.gradient.end = transformed_mouse,
+			GradientDragTarget::New => {
+				self.gradient.start = self.transform.inverse().transform_point2(drag_start);
+				self.gradient.end = transformed_mouse;
+			}
 			GradientDragTarget::Step(s) => {
 				let (start, end) = (self.transform.transform_point2(self.gradient.start), self.transform.transform_point2(self.gradient.end));
 
@@ -259,6 +294,7 @@ impl ToolTransition for GradientTool {
 	fn event_to_message_map(&self) -> EventToMessageMap {
 		EventToMessageMap {
 			tool_abort: Some(GradientToolMessage::Abort.into()),
+			selection_changed: Some(GradientToolMessage::SelectionChanged.into()),
 			overlay_provider: Some(|context| GradientToolMessage::Overlays { context }.into()),
 			..Default::default()
 		}
@@ -297,6 +333,7 @@ impl Fsm for GradientToolFsmState {
 		match (self, event) {
 			(_, GradientToolMessage::Overlays { context: mut overlay_context }) => {
 				let selected = tool_data.selected_gradient.as_ref();
+				let mouse = input.mouse.position;
 
 				for layer in document.network_interface.selected_nodes().selected_visible_layers(&document.network_interface) {
 					let Some(gradient) = get_gradient(layer, &document.network_interface) else { continue };
@@ -305,25 +342,49 @@ impl Fsm for GradientToolFsmState {
 						.filter(|selected| selected.layer.is_some_and(|selected_layer| selected_layer == layer))
 						.map(|selected| selected.dragging);
 
+					let gradient = if dragging.is_some()
+						&& let Some(selected_gradient) = selected.filter(|s| s.layer == Some(layer))
+					{
+						&selected_gradient.gradient
+					} else {
+						&gradient
+					};
+
 					let Gradient { start, end, stops, .. } = gradient;
-					let (start, end) = (transform.transform_point2(start), transform.transform_point2(end));
+					let (start, end) = (transform.transform_point2(*start), transform.transform_point2(*end));
+
+					fn color_to_hex(color: graphene_std::Color) -> String {
+						format!("#{}", color.with_alpha(1.).to_rgba_hex_srgb())
+					}
+
+					let start_hex = stops.first().map(|(_, c)| color_to_hex(*c)).unwrap_or(String::from(COLOR_OVERLAY_BLUE));
+					let end_hex = stops.last().map(|(_, c)| color_to_hex(*c)).unwrap_or(String::from(COLOR_OVERLAY_BLUE));
 
 					overlay_context.line(start, end, None, None);
-					overlay_context.manipulator_handle(start, dragging == Some(GradientDragTarget::Start), None);
+					overlay_context.gradient_color_stop(start, dragging == Some(GradientDragTarget::Start), &start_hex);
-					overlay_context.manipulator_handle(end, dragging == Some(GradientDragTarget::End), None);
+					overlay_context.gradient_color_stop(end, dragging == Some(GradientDragTarget::End), &end_hex);
 
-					for (index, (position, _)) in stops.into_iter().enumerate() {
+					for (index, (position, color)) in stops.clone().into_iter().enumerate() {
 						if position.abs() < f64::EPSILON * 1000. || (1. - position).abs() < f64::EPSILON * 1000. {
 							continue;
 						}
+						overlay_context.gradient_color_stop(start.lerp(end, position), dragging == Some(GradientDragTarget::Step(index)), &color_to_hex(color));
+					}
 
-						overlay_context.manipulator_handle(start.lerp(end, position), dragging == Some(GradientDragTarget::Step(index)), None);
+					if let (Some(projection), Some(dir)) = (calculate_insertion(start, end, stops, mouse), (end - start).try_normalize()) {
+						let perp = dir.perp();
+						let point = start.lerp(end, projection);
+						overlay_context.line(point - perp * SEGMENT_OVERLAY_SIZE, point + perp * SEGMENT_OVERLAY_SIZE, Some(COLOR_OVERLAY_BLUE), Some(1.));
 					}
 				}
 
 				self
 			}
-			(GradientToolFsmState::Ready, GradientToolMessage::DeleteStop) => {
+			(GradientToolFsmState::Ready { .. }, GradientToolMessage::SelectionChanged) => {
+				tool_data.selected_gradient = None;
+				self
+			}
+			(GradientToolFsmState::Ready { .. }, GradientToolMessage::DeleteStop) => {
 				let Some(selected_gradient) = &mut tool_data.selected_gradient else {
 					return self;
 				};
@@ -333,7 +394,7 @@ impl Fsm for GradientToolFsmState {
 					return self;
 				}
 
-				responses.add(DocumentMessage::AddTransaction);
+				responses.add(DocumentMessage::StartTransaction);
 
 				// Remove the selected point
 				match selected_gradient.dragging {
@@ -346,6 +407,7 @@ impl Fsm for GradientToolFsmState {
 					GradientDragTarget::Step(index) => {
 						selected_gradient.gradient.stops.remove(index);
 					}
+					GradientDragTarget::New => {}
 				};
 
 				// The gradient has only one point and so should become a fill
@@ -356,6 +418,8 @@ impl Fsm for GradientToolFsmState {
 							fill: Fill::Solid(selected_gradient.gradient.stops[0].1),
 						});
 					}
+					responses.add(DocumentMessage::CommitTransaction);
+					responses.add(PropertiesPanelMessage::Refresh);
 					return self;
 				}
 
@@ -377,6 +441,9 @@ impl Fsm for GradientToolFsmState {
 
 				// Render the new gradient
 				selected_gradient.render_gradient(responses);
+				responses.add(DocumentMessage::CommitTransaction);
+				responses.add(PropertiesPanelMessage::Refresh);
+				tool_data.selected_gradient = None;
 
 				self
 			}
@@ -395,7 +462,7 @@ impl Fsm for GradientToolFsmState {
 					if distance < (SELECTION_THRESHOLD * 2.) {
 						// Try and insert the new stop
 						if let Some(index) = gradient.insert_stop(mouse, transform) {
-							responses.add(DocumentMessage::AddTransaction);
+							responses.add(DocumentMessage::StartTransaction);
 
 							let mut selected_gradient = SelectedGradient::new(gradient, layer, document);
 
@@ -406,7 +473,7 @@ impl Fsm for GradientToolFsmState {
 							selected_gradient.render_gradient(responses);
 
 							tool_data.selected_gradient = Some(selected_gradient);
-
+							responses.add(DocumentMessage::CommitTransaction);
 							break;
 						}
 					}
@@ -414,12 +481,13 @@ impl Fsm for GradientToolFsmState {
 
 				self
 			}
-			(GradientToolFsmState::Ready, GradientToolMessage::PointerDown) => {
+			(GradientToolFsmState::Ready { .. }, GradientToolMessage::PointerDown) => {
 				let mouse = input.mouse.position;
 				tool_data.drag_start = mouse;
 				let tolerance = (MANIPULATOR_GROUP_MARKER_SIZE * 2.).powi(2);
 
 				let mut dragging = false;
+				let mut transaction_started = false;
 				for layer in document.network_interface.selected_nodes().selected_visible_layers(&document.network_interface) {
 					let Some(gradient) = get_gradient(layer, &document.network_interface) else { continue };
 					let transform = gradient_space_transform(layer, document);
@@ -433,6 +501,7 @@ impl Fsm for GradientToolFsmState {
 								transform,
 								gradient: gradient.clone(),
 								dragging: GradientDragTarget::Step(index),
+								initial_gradient: gradient.clone(),
 							})
 						}
 					}
@@ -447,9 +516,34 @@ impl Fsm for GradientToolFsmState {
 								transform,
 								gradient: gradient.clone(),
 								dragging: dragging_target,
+								initial_gradient: gradient.clone(),
 							})
 						}
 					}
+
+					// Insert stop if clicking on line
+					if !dragging {
+						let (start, end) = (transform.transform_point2(gradient.start), transform.transform_point2(gradient.end));
+						let distance = (end - start).angle_to(mouse - start).sin() * (mouse - start).length();
+						let projection = ((end - start).angle_to(mouse - start)).cos() * start.distance(mouse) / start.distance(end);
+
+						if distance.abs() < SEGMENT_INSERTION_DISTANCE
+							&& (0. ..=1.).contains(&projection)
+							&& let Some(index) = gradient.clone().insert_stop(mouse, transform)
+						{
+							responses.add(DocumentMessage::StartTransaction);
+							transaction_started = true;
+							let mut new_gradient = gradient.clone();
+							new_gradient.insert_stop(mouse, transform);
+
+							let mut selected_gradient = SelectedGradient::new(new_gradient, layer, document);
+							selected_gradient.dragging = GradientDragTarget::Step(index);
+							// No offset when inserting a new stop, it should be exactly under the mouse
+							selected_gradient.render_gradient(responses);
+							tool_data.selected_gradient = Some(selected_gradient);
+							dragging = true;
+						}
+					}
 				}
 
 				let gradient_state = if dragging {
@@ -461,7 +555,7 @@ impl Fsm for GradientToolFsmState {
 					if let Some(layer) = selected_layer {
 						// Add check for raster layer
 						if NodeGraphLayer::is_raster_layer(layer, &mut document.network_interface) {
-							return GradientToolFsmState::Ready;
+							return GradientToolFsmState::Ready { hover_insertion: false };
 						}
 						if !document.network_interface.selected_nodes().selected_layers_contains(layer, document.metadata()) {
 							let nodes = vec![layer.to_node()];
@@ -476,22 +570,35 @@ impl Fsm for GradientToolFsmState {
 							// Generate a new gradient
 							Gradient::new(DVec2::ZERO, global_tool_data.secondary_color, DVec2::ONE, global_tool_data.primary_color, tool_options.gradient_type)
 						};
-						let selected_gradient = SelectedGradient::new(gradient, layer, document).with_gradient_start(input.mouse.position);
+						let mut selected_gradient = SelectedGradient::new(gradient, layer, document);
+						selected_gradient.dragging = GradientDragTarget::New;
 
 						tool_data.selected_gradient = Some(selected_gradient);
 
 						GradientToolFsmState::Drawing
 					} else {
-						GradientToolFsmState::Ready
+						GradientToolFsmState::Ready { hover_insertion: false }
 					}
 				};
-				responses.add(DocumentMessage::StartTransaction);
+
+				if gradient_state == GradientToolFsmState::Drawing && !transaction_started {
+					responses.add(DocumentMessage::StartTransaction);
+				}
+
+				responses.add(OverlaysMessage::Draw);
+
 				gradient_state
 			}
 			(GradientToolFsmState::Drawing, GradientToolMessage::PointerMove { constrain_axis }) => {
 				if let Some(selected_gradient) = &mut tool_data.selected_gradient {
 					let mouse = input.mouse.position; // tool_data.snap_manager.snap_position(responses, document, input.mouse.position);
-					selected_gradient.update_gradient(mouse, responses, input.keyboard.get(constrain_axis as usize), selected_gradient.gradient.gradient_type);
+					selected_gradient.update_gradient(
+						mouse,
+						responses,
+						input.keyboard.get(constrain_axis as usize),
+						selected_gradient.gradient.gradient_type,
+						tool_data.drag_start,
+					);
 				}
 
 				// Auto-panning
@@ -501,6 +608,8 @@ impl Fsm for GradientToolFsmState {
 				];
 				tool_data.auto_panning.setup_by_mouse_position(input, viewport, &messages, responses);
 
+				responses.add(OverlaysMessage::Draw);
+
 				GradientToolFsmState::Drawing
 			}
 			(GradientToolFsmState::Drawing, GradientToolMessage::PointerOutsideViewport { .. }) => {
@@ -524,7 +633,7 @@ impl Fsm for GradientToolFsmState {
 				state
 			}
 			(GradientToolFsmState::Drawing, GradientToolMessage::PointerUp) => {
-				input.mouse.finish_transaction(tool_data.drag_start, responses);
+				responses.add(DocumentMessage::EndTransaction);
 				tool_data.snap_manager.cleanup(responses);
 				let was_dragging = tool_data.selected_gradient.is_some();
 
@@ -534,27 +643,51 @@ impl Fsm for GradientToolFsmState {
 				{
 					tool_data.selected_gradient = Some(SelectedGradient::new(gradient, selected_layer, document));
 				}
-				GradientToolFsmState::Ready
+				GradientToolFsmState::Ready { hover_insertion: false }
+			}
+			(GradientToolFsmState::Ready { .. }, GradientToolMessage::PointerMove { .. }) => {
+				let mut hover_insertion = false;
+				let mouse = input.mouse.position;
+
+				for layer in document.network_interface.selected_nodes().selected_visible_layers(&document.network_interface) {
+					let Some(gradient) = get_gradient(layer, &document.network_interface) else { continue };
+					let transform = gradient_space_transform(layer, document);
+					let start = transform.transform_point2(gradient.start);
+					let end = transform.transform_point2(gradient.end);
+
+					if calculate_insertion(start, end, &gradient.stops, mouse).is_some() {
+						hover_insertion = true;
+						break;
+					}
+				}
+
+				responses.add(OverlaysMessage::Draw);
+				GradientToolFsmState::Ready { hover_insertion }
 			}
 
 			(GradientToolFsmState::Drawing, GradientToolMessage::Abort) => {
 				responses.add(DocumentMessage::AbortTransaction);
 				tool_data.snap_manager.cleanup(responses);
+				tool_data.selected_gradient = None;
 				responses.add(OverlaysMessage::Draw);
 
-				GradientToolFsmState::Ready
+				GradientToolFsmState::Ready { hover_insertion: false }
 			}
-			(_, GradientToolMessage::Abort) => GradientToolFsmState::Ready,
+			(_, GradientToolMessage::Abort) => GradientToolFsmState::Ready { hover_insertion: false },
 			_ => self,
 		}
 	}
 
 	fn update_hints(&self, responses: &mut VecDeque<Message>) {
 		let hint_data = match self {
-			GradientToolFsmState::Ready => HintData(vec![HintGroup(vec![
+			GradientToolFsmState::Ready { hover_insertion } => {
-				HintInfo::mouse(MouseMotion::LmbDrag, "Draw Gradient"),
+				let hints = if *hover_insertion {
-				HintInfo::keys([Key::Shift], "15° Increments").prepend_plus(),
+					vec![HintInfo::mouse(MouseMotion::Lmb, "Insert Color Stop")]
-			])]),
+				} else {
+					vec![HintInfo::mouse(MouseMotion::LmbDrag, "Draw Gradient"), HintInfo::keys([Key::Shift], "15° Increments").prepend_plus()]
+				};
+				HintData(vec![HintGroup(hints)])
+			}
 			GradientToolFsmState::Drawing => HintData(vec![
 				HintGroup(vec![HintInfo::mouse(MouseMotion::Rmb, ""), HintInfo::keys([Key::Escape], "Cancel").prepend_slash()]),
 				HintGroup(vec![HintInfo::keys([Key::Shift], "15° Increments")]),
@@ -724,7 +857,7 @@ mod test_gradient {
 	}
 
 	#[tokio::test]
-	async fn double_click_insert_stop() {
+	async fn click_to_insert_stop() {
 		let mut editor = EditorTestUtils::create();
 		editor.new_document().await;
 
@@ -738,7 +871,9 @@ mod test_gradient {
 		assert_eq!(initial_gradient.stops.len(), 2, "Expected 2 stops, found {}", initial_gradient.stops.len());
 
 		editor.select_tool(ToolType::Gradient).await;
-		editor.double_click(DVec2::new(50., 0.)).await;
+		editor.move_mouse(50., 0., ModifierKeys::empty(), MouseKeys::empty()).await;
+		editor.left_mousedown(50., 0., ModifierKeys::empty()).await;
+		editor.left_mouseup(50., 0., ModifierKeys::empty()).await;
 
 		// Check that a new stop has been added
 		let (updated_gradient, _) = get_gradient(&mut editor).await;
@@ -831,7 +966,9 @@ mod test_gradient {
 		editor.select_tool(ToolType::Gradient).await;
 
 		// Add a middle stop at 50%
-		editor.double_click(DVec2::new(50., 0.)).await;
+		editor.move_mouse(50., 0., ModifierKeys::empty(), MouseKeys::empty()).await;
+		editor.left_mousedown(50., 0., ModifierKeys::empty()).await;
+		editor.left_mouseup(50., 0., ModifierKeys::empty()).await;
 
 		let (initial_gradient, _) = get_gradient(&mut editor).await;
 		assert_eq!(initial_gradient.stops.len(), 3, "Expected 3 stops, found {}", initial_gradient.stops.len());
@@ -906,8 +1043,13 @@ mod test_gradient {
 		editor.select_tool(ToolType::Gradient).await;
 
 		// Add two middle stops
-		editor.double_click(DVec2::new(25., 0.)).await;
+		editor.move_mouse(25., 0., ModifierKeys::empty(), MouseKeys::empty()).await;
-		editor.double_click(DVec2::new(75., 0.)).await;
+		editor.left_mousedown(25., 0., ModifierKeys::empty()).await;
+		editor.left_mouseup(25., 0., ModifierKeys::empty()).await;
+
+		editor.move_mouse(75., 0., ModifierKeys::empty(), MouseKeys::empty()).await;
+		editor.left_mousedown(75., 0., ModifierKeys::empty()).await;
+		editor.left_mouseup(75., 0., ModifierKeys::empty()).await;
 
 		let (updated_gradient, _) = get_gradient(&mut editor).await;
 		assert_eq!(updated_gradient.stops.len(), 4, "Expected 4 stops, found {}", updated_gradient.stops.len());

editor/src/test_utils.rs

@@ -210,6 +210,18 @@ impl EditorTestUtils {
 		.await;
 	}
 
+	pub async fn left_mouseup(&mut self, x: f64, y: f64, modifier_keys: ModifierKeys) {
+		self.mouseup(
+			EditorMouseState {
+				editor_position: (x, y).into(),
+				mouse_keys: MouseKeys::empty(),
+				scroll_delta: ScrollDelta::default(),
+			},
+			modifier_keys,
+		)
+		.await;
+	}
+
 	pub async fn input(&mut self, message: InputPreprocessorMessage) {
 		self.handle_message(Message::InputPreprocessor(message)).await;
 	}