Fix the Path tool's segment insertion line overlay having hysteresis with distance away from the cursor (#2677)

* Fix hysteresis in segment insertion

* Update editor/src/messages/tool/common_functionality/shape_editor.rs

* Update editor/src/messages/tool/common_functionality/shape_editor.rs

* Fix insert point overlay

---------

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

Author: 4adex

editor/src/consts.rs

@@ -102,7 +102,7 @@ pub const MANIPULATOR_GROUP_MARKER_SIZE: f64 = 6.;
 pub const SELECTION_THRESHOLD: f64 = 10.;
 pub const HIDE_HANDLE_DISTANCE: f64 = 3.;
 pub const HANDLE_ROTATE_SNAP_ANGLE: f64 = 15.;
-pub const SEGMENT_INSERTION_DISTANCE: f64 = 7.5;
+pub const SEGMENT_INSERTION_DISTANCE: f64 = 8.;
 pub const SEGMENT_OVERLAY_SIZE: f64 = 10.;
 pub const HANDLE_LENGTH_FACTOR: f64 = 0.5;
 

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

@@ -1,4 +1,4 @@
-use super::graph_modification_utils::{self, merge_layers};
+use super::graph_modification_utils::merge_layers;
 use super::snapping::{SnapCache, SnapCandidatePoint, SnapData, SnapManager, SnappedPoint};
 use super::utility_functions::calculate_segment_angle;
 use crate::consts::HANDLE_LENGTH_FACTOR;
@@ -12,7 +12,6 @@ use crate::messages::tool::common_functionality::utility_functions::is_visible_p
 use crate::messages::tool::tool_messages::path_tool::{PathOverlayMode, PointSelectState};
 use bezier_rs::{Bezier, BezierHandles, Subpath, TValue};
 use glam::{DAffine2, DVec2};
-use graphene_core::transform::Transform;
 use graphene_core::vector::{ManipulatorPointId, PointId, VectorData, VectorModificationType};
 use graphene_std::vector::{HandleId, SegmentId};
 
@@ -149,7 +148,6 @@ pub struct ClosestSegment {
 	colinear: [Option<HandleId>; 2],
 	t: f64,
 	bezier_point_to_viewport: DVec2,
-	stroke_width: f64,
 }
 
 impl ClosestSegment {
@@ -169,6 +167,12 @@ impl ClosestSegment {
 		self.bezier_point_to_viewport
 	}
 
+	pub fn closest_point(&self, document_metadata: &DocumentMetadata) -> DVec2 {
+		let transform = document_metadata.transform_to_viewport(self.layer);
+		let bezier_point = self.bezier.evaluate(TValue::Parametric(self.t));
+		transform.transform_point2(bezier_point)
+	}
+
 	/// Updates this [`ClosestSegment`] with the viewport-space location of the closest point on the segment to the given mouse position.
 	pub fn update_closest_point(&mut self, document_metadata: &DocumentMetadata, mouse_position: DVec2) {
 		let transform = document_metadata.transform_to_viewport(self.layer);
@@ -186,10 +190,8 @@ impl ClosestSegment {
 		self.bezier_point_to_viewport.distance_squared(mouse_position)
 	}
 
-	pub fn too_far(&self, mouse_position: DVec2, tolerance: f64, document_metadata: &DocumentMetadata) -> bool {
-		let dist_sq = self.distance_squared(mouse_position);
-		let stroke_width = document_metadata.document_to_viewport.decompose_scale().x.max(1.) * self.stroke_width;
-		(stroke_width + tolerance).powi(2) < dist_sq
+	pub fn too_far(&self, mouse_position: DVec2, tolerance: f64) -> bool {
+		tolerance.powi(2) < self.distance_squared(mouse_position)
 	}
 
 	pub fn handle_positions(&self, document_metadata: &DocumentMetadata) -> (Option<DVec2>, Option<DVec2>) {
@@ -1449,11 +1451,6 @@ impl ShapeState {
 			if distance_squared < closest_distance_squared {
 				closest_distance_squared = distance_squared;
 
-				// 0.5 is half the line (center to side) but it's convenient to allow targeting slightly more than half the line width
-				const STROKE_WIDTH_PERCENT: f64 = 0.7;
-
-				let stroke_width = graph_modification_utils::get_stroke_width(layer, network_interface).unwrap_or(1.) as f64 * STROKE_WIDTH_PERCENT;
-
 				// Convert to linear if handes are on top of control points
 				if let bezier_rs::BezierHandles::Cubic { handle_start, handle_end } = bezier.handles {
 					if handle_start.abs_diff_eq(bezier.start(), f64::EPSILON * 100.) && handle_end.abs_diff_eq(bezier.end(), f64::EPSILON * 100.) {
@@ -1474,7 +1471,6 @@ impl ShapeState {
 					t,
 					bezier_point_to_viewport: screenspace,
 					layer,
-					stroke_width,
 				});
 			}
 		}

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

@@ -1129,7 +1129,7 @@ impl Fsm for PathToolFsmState {
 					Self::Ready => {
 						if let Some(closest_segment) = &tool_data.segment {
 							let perp = closest_segment.calculate_perp(document);
-							let point = closest_segment.closest_point_to_viewport();
+							let point = closest_segment.closest_point(document.metadata());
 
 							// Draw an X on the segment
 							if tool_data.delete_segment_pressed {
@@ -1400,7 +1400,7 @@ impl Fsm for PathToolFsmState {
 				// If already hovering on a segment, then recalculate its closest point
 				else if let Some(closest_segment) = &mut tool_data.segment {
 					closest_segment.update_closest_point(document.metadata(), input.mouse.position);
-					if closest_segment.too_far(input.mouse.position, SEGMENT_INSERTION_DISTANCE, document.metadata()) {
+					if closest_segment.too_far(input.mouse.position, SEGMENT_INSERTION_DISTANCE) {
 						tool_data.segment = None;
 					}
 					responses.add(OverlaysMessage::Draw)