From e04b980dff8a71fd6ef06c19f5966f8e8ab86703 Mon Sep 17 00:00:00 2001
From: Alex Grozav <alex@grozav.com>
Date: Tue, 1 Oct 2024 16:43:47 +0300
Subject: [PATCH] feat(editor): Improve edges and connection lines rendering on
 new canvas (no-changelog) (#11036)

---
 .../edges/CanvasConnectionLine.spec.ts        |  4 +--
 .../elements/edges/CanvasConnectionLine.vue   | 21 ++++++++++-
 .../canvas/elements/edges/CanvasEdge.spec.ts  | 26 +++++++++++++-
 .../canvas/elements/edges/CanvasEdge.vue      | 13 ++++---
 .../canvas/elements/edges/utils/edgePath.ts   | 36 +++++++++++--------
 5 files changed, 78 insertions(+), 22 deletions(-)

diff --git a/packages/editor-ui/src/components/canvas/elements/edges/CanvasConnectionLine.spec.ts b/packages/editor-ui/src/components/canvas/elements/edges/CanvasConnectionLine.spec.ts
index 7591a8666..812dd7eff 100644
--- a/packages/editor-ui/src/components/canvas/elements/edges/CanvasConnectionLine.spec.ts
+++ b/packages/editor-ui/src/components/canvas/elements/edges/CanvasConnectionLine.spec.ts
@@ -50,7 +50,7 @@ describe('CanvasConnectionLine', () => {
 
 		expect(edge).toHaveAttribute(
 			'd',
-			'M0 0L 32,0Q 40,0 40,8L 40,132Q 40,140 32,140L1 140L0 140M0 140L-40 140L -132,140Q -140,140 -140,132L -140,-92Q -140,-100 -132,-100L-100 -100',
+			'M0 0L 24,0Q 40,0 40,16L 40,124Q 40,140 24,140L1 140L0 140M0 140L-40 140L -124,140Q -140,140 -140,124L -140,-84Q -140,-100 -124,-100L-100 -100',
 		);
 	});
 
@@ -71,7 +71,7 @@ describe('CanvasConnectionLine', () => {
 
 		expect(edge).toHaveAttribute(
 			'd',
-			'M-72 -290L -57,-290Q -52,-290 -52,-285L -52,-165Q -52,-160 -57,-160L -359,-160Q -364,-160 -364,-155L -364,-35Q -364,-30 -359,-30L-344 -30',
+			'M-72 -290L -62,-290Q -52,-290 -52,-280L -52,-176Q -52,-160 -68,-160L -348,-160Q -364,-160 -364,-144L -364,-40Q -364,-30 -354,-30L-344 -30',
 		);
 	});
 });
diff --git a/packages/editor-ui/src/components/canvas/elements/edges/CanvasConnectionLine.vue b/packages/editor-ui/src/components/canvas/elements/edges/CanvasConnectionLine.vue
index 86b1a5971..8cb47fab9 100644
--- a/packages/editor-ui/src/components/canvas/elements/edges/CanvasConnectionLine.vue
+++ b/packages/editor-ui/src/components/canvas/elements/edges/CanvasConnectionLine.vue
@@ -4,16 +4,35 @@ import type { ConnectionLineProps } from '@vue-flow/core';
 import { BaseEdge } from '@vue-flow/core';
 import { computed, useCssModule } from 'vue';
 import { getCustomPath } from './utils/edgePath';
+import { useCanvas } from '@/composables/useCanvas';
+import { NodeConnectionType } from 'n8n-workflow';
+import { parseCanvasConnectionHandleString } from '@/utils/canvasUtilsV2';
 
 const props = defineProps<ConnectionLineProps>();
 
 const $style = useCssModule();
 
+const { connectingHandle } = useCanvas();
+
+const connectionType = computed(
+	() => parseCanvasConnectionHandleString(connectingHandle.value?.handleId).type,
+);
+
+const edgeColor = computed(() => {
+	if (connectionType.value !== NodeConnectionType.Main) {
+		return 'var(--node-type-supplemental-color)';
+	} else {
+		return 'var(--color-foreground-xdark)';
+	}
+});
+
 const edgeStyle = computed(() => ({
+	...(connectionType.value === NodeConnectionType.Main ? {} : { strokeDasharray: '8,8' }),
 	strokeWidth: 2,
+	stroke: edgeColor.value,
 }));
 
-const path = computed(() => getCustomPath(props));
+const path = computed(() => getCustomPath(props, { connectionType: connectionType.value }));
 </script>
 
 <template>
diff --git a/packages/editor-ui/src/components/canvas/elements/edges/CanvasEdge.spec.ts b/packages/editor-ui/src/components/canvas/elements/edges/CanvasEdge.spec.ts
index 93ca4f13f..6a8ce9e78 100644
--- a/packages/editor-ui/src/components/canvas/elements/edges/CanvasEdge.spec.ts
+++ b/packages/editor-ui/src/components/canvas/elements/edges/CanvasEdge.spec.ts
@@ -124,7 +124,31 @@ describe('CanvasEdge', () => {
 
 		expect(edge).toHaveAttribute(
 			'd',
-			'M0 0L 32,0Q 40,0 40,8L 40,132Q 40,140 32,140L1 140L0 140M0 140L-40 140L -132,140Q -140,140 -140,132L -140,-92Q -140,-100 -132,-100L-100 -100',
+			'M0 0L 24,0Q 40,0 40,16L 40,124Q 40,140 24,140L1 140L0 140M0 140L-40 140L -124,140Q -140,140 -140,124L -140,-84Q -140,-100 -124,-100L-100 -100',
 		);
 	});
+
+	it('should render a correct bezier path when the connection is backwards and node connection type is non-main', () => {
+		const { container } = renderComponent({
+			props: {
+				...DEFAULT_PROPS,
+				data: {
+					...DEFAULT_PROPS.data,
+					source: {
+						type: NodeConnectionType.AiTool,
+					},
+				},
+				sourceX: 0,
+				sourceY: 0,
+				sourcePosition: Position.Right,
+				targetX: -100,
+				targetY: -100,
+				targetPosition: Position.Left,
+			},
+		});
+
+		const edge = container.querySelector('.vue-flow__edge-path');
+
+		expect(edge).toHaveAttribute('d', 'M0,0 C62.5,0 -162.5,-100 -100,-100');
+	});
 });
diff --git a/packages/editor-ui/src/components/canvas/elements/edges/CanvasEdge.vue b/packages/editor-ui/src/components/canvas/elements/edges/CanvasEdge.vue
index 1c08cea43..fc39d481a 100644
--- a/packages/editor-ui/src/components/canvas/elements/edges/CanvasEdge.vue
+++ b/packages/editor-ui/src/components/canvas/elements/edges/CanvasEdge.vue
@@ -49,7 +49,8 @@ const renderToolbar = computed(() => (props.selected || isHovered.value) && !pro
 const isMainConnection = computed(() => data.value.source.type === NodeConnectionType.Main);
 
 const status = computed(() => props.data.status);
-const statusColor = computed(() => {
+
+const edgeColor = computed(() => {
 	if (props.selected) {
 		return 'var(--color-background-dark)';
 	} else if (status.value === 'success') {
@@ -69,10 +70,10 @@ const edgeStyle = computed(() => ({
 	...props.style,
 	...(isMainConnection.value ? {} : { strokeDasharray: '8,8' }),
 	strokeWidth: 2,
-	stroke: isHovered.value ? 'var(--color-primary)' : statusColor.value,
+	stroke: isHovered.value ? 'var(--color-primary)' : edgeColor.value,
 }));
 
-const edgeLabelStyle = computed(() => ({ color: statusColor.value }));
+const edgeLabelStyle = computed(() => ({ color: edgeColor.value }));
 
 const edgeToolbarStyle = computed(() => {
 	const [, labelX, labelY] = path.value;
@@ -81,7 +82,11 @@ const edgeToolbarStyle = computed(() => {
 	};
 });
 
-const path = computed(() => getCustomPath(props));
+const path = computed(() =>
+	getCustomPath(props, {
+		connectionType: connectionType.value,
+	}),
+);
 
 const connection = computed<Connection>(() => ({
 	source: props.source,
diff --git a/packages/editor-ui/src/components/canvas/elements/edges/utils/edgePath.ts b/packages/editor-ui/src/components/canvas/elements/edges/utils/edgePath.ts
index 8975641a1..053fda35a 100644
--- a/packages/editor-ui/src/components/canvas/elements/edges/utils/edgePath.ts
+++ b/packages/editor-ui/src/components/canvas/elements/edges/utils/edgePath.ts
@@ -1,38 +1,43 @@
 import type { EdgeProps } from '@vue-flow/core';
 import { getBezierPath, getSmoothStepPath, Position } from '@vue-flow/core';
+import { NodeConnectionType } from 'n8n-workflow';
 
-const EDGE_PADDING_Y = 140;
-const EDGE_PADDING_Y_TOP = 80;
-const EDGE_BORDER_RADIUS = 8;
-const EDGE_OFFSET = 40;
-// const HANDLE_SIZE = 16;
+const EDGE_PADDING_TOP = 80;
+const EDGE_PADDING_BOTTOM = 140;
+const EDGE_PADDING_X = 40;
+const EDGE_BORDER_RADIUS = 16;
+const HANDLE_SIZE = 20; // Required to avoid connection line glitching when initially interacting with the handle
 
-const isTargetHandlePositionedLeftOfSourceTarget = (sourceX: number, targetX: number) =>
-	sourceX > targetX;
+const isRightOfSourceHandle = (sourceX: number, targetX: number) => sourceX - HANDLE_SIZE > targetX;
 
 const pathIntersectsNodes = (targetY: number, sourceY: number) =>
-	Math.abs(targetY - sourceY) < EDGE_PADDING_Y;
+	Math.abs(targetY - sourceY) < EDGE_PADDING_BOTTOM;
 
 export function getCustomPath(
 	props: Pick<
 		EdgeProps,
 		'sourceX' | 'sourceY' | 'sourcePosition' | 'targetX' | 'targetY' | 'targetPosition'
 	>,
+	{
+		connectionType = NodeConnectionType.Main,
+	}: {
+		connectionType?: NodeConnectionType;
+	} = {},
 ) {
 	const { targetX, targetY, sourceX, sourceY, sourcePosition, targetPosition } = props;
 	const yDiff = targetY - sourceY;
 
-	if (!isTargetHandlePositionedLeftOfSourceTarget(sourceX, targetX)) {
+	if (!isRightOfSourceHandle(sourceX, targetX) || connectionType !== NodeConnectionType.Main) {
 		return getBezierPath(props);
 	}
 
 	// Connection is backwards and the source is on the right side
 	// -> We need to avoid overlapping the source node
 	if (pathIntersectsNodes(targetY, sourceY)) {
-		const direction = yDiff < -EDGE_PADDING_Y || yDiff > 0 ? 'up' : 'down';
+		const direction = yDiff < -EDGE_PADDING_BOTTOM || yDiff > 0 ? 'up' : 'down';
 		const firstSegmentTargetX = sourceX;
 		const firstSegmentTargetY =
-			sourceY + (direction === 'up' ? -EDGE_PADDING_Y_TOP : EDGE_PADDING_Y);
+			sourceY + (direction === 'up' ? -EDGE_PADDING_TOP : EDGE_PADDING_BOTTOM);
 		const [firstSegmentPath] = getSmoothStepPath({
 			sourceX,
 			sourceY,
@@ -41,7 +46,7 @@ export function getCustomPath(
 			sourcePosition,
 			targetPosition: Position.Right,
 			borderRadius: EDGE_BORDER_RADIUS,
-			offset: EDGE_OFFSET,
+			offset: EDGE_PADDING_X,
 		});
 		const path = getSmoothStepPath({
 			sourceX: firstSegmentTargetX,
@@ -51,12 +56,15 @@ export function getCustomPath(
 			sourcePosition: Position.Left,
 			targetPosition,
 			borderRadius: EDGE_BORDER_RADIUS,
-			offset: EDGE_OFFSET,
+			offset: EDGE_PADDING_X,
 		});
 
 		path[0] = firstSegmentPath + path[0];
 		return path;
 	}
 
-	return getSmoothStepPath(props);
+	return getSmoothStepPath({
+		...props,
+		borderRadius: EDGE_BORDER_RADIUS,
+	});
 }