feat(svelte): add snapGrid

packages/svelte/src/lib/actions/drag/index.ts

@@ -5,6 +5,7 @@ import type { XYPosition, CoordinateExtent, Transform } from '@reactflow/system'
 
 import { getDragItems, hasSelector, calcNextPosition } from './utils';
 import type { Node } from '$lib/types';
+import type { SvelteFlowStore } from '$lib/store/types';
 
 export type UseDragData = { dx: number; dy: number };
 export type UseDragEvent = D3DragEvent<HTMLDivElement, null, SubjectPosition>;
@@ -25,13 +26,21 @@ type UseDragParams = {
   handleSelector?: string;
   nodeId?: string;
   updateNodePositions: (dragItems: NodeDragItem[], d: boolean, p: boolean) => void;
-  nodes: Writable<Node[]>;
-  transform: Writable<Transform>;
+  nodes: SvelteFlowStore['nodes'];
+  transform: SvelteFlowStore['transform'];
+  snapGrid: SvelteFlowStore['snapGrid'];
 };
 
 export default function drag(
   nodeRef: Element,
-  { handleSelector, nodeId, updateNodePositions, nodes, transform: transformStore }: UseDragParams
+  {
+    handleSelector,
+    nodeId,
+    updateNodePositions,
+    nodes,
+    transform: transformStore,
+    snapGrid: snapGridStore
+  }: UseDragParams
 ) {
   let dragging = false;
   let dragItems: NodeDragItem[] = [];
@@ -43,6 +52,7 @@ export default function drag(
     const x = sourceEvent.touches ? sourceEvent.touches[0].clientX : sourceEvent.clientX;
     const y = sourceEvent.touches ? sourceEvent.touches[0].clientY : sourceEvent.clientY;
     const transform = get(transformStore);
+    const snapGrid = get(snapGridStore);
 
     const pointerPos = {
       x: (x - transform[0]) / transform[2],
@@ -51,17 +61,24 @@ export default function drag(
 
     // we need the snapped position in order to be able to skip unnecessary drag events
     return {
-      xSnapped: pointerPos.x,
-      ySnapped: pointerPos.y,
+      xSnapped: snapGrid ? snapGrid[0] * Math.round(pointerPos.x / snapGrid[0]) : pointerPos.x,
+      ySnapped: snapGrid ? snapGrid[1] * Math.round(pointerPos.y / snapGrid[1]) : pointerPos.y,
       ...pointerPos
     };
   };
 
   const updateNodes = ({ x, y }: XYPosition) => {
     let hasChange = false;
+    const snapGrid = get(snapGridStore);
 
     dragItems = dragItems.map((n) => {
       const nextPosition = { x: x - n.distance.x, y: y - n.distance.y };
+
+      if (snapGrid) {
+        nextPosition.x = snapGrid[0] * Math.round(nextPosition.x / snapGrid[0]);
+        nextPosition.y = snapGrid[1] * Math.round(nextPosition.y / snapGrid[1]);
+      }
+
       const updatedPos = calcNextPosition(n, nextPosition, get(nodes));
 
       // we want to make sure that we only fire a change event when there is a changes

packages/svelte/src/lib/components/NodeSelection/NodeSelection.svelte

@@ -5,7 +5,7 @@
   import { Selection } from '$lib/components/Selection';
   import drag from '$lib/actions/drag';
 
-  const { selectionRectMode, nodes, transform, updateNodePositions } = useStore();
+  const { selectionRectMode, nodes, transform, snapGrid, updateNodePositions } = useStore();
 
   $: selectedNodes = $nodes.filter((n) => n.selected);
   $: rect = getRectOfNodes(selectedNodes);
@@ -15,7 +15,7 @@
   <div
     class="selection-wrapper nopan"
     style={`width: ${rect.width}px; height: ${rect.height}px; transform: translate(${rect.x}px, ${rect.y}px)`}
-    use:drag={{ nodes, transform, updateNodePositions }}
+    use:drag={{ nodes, snapGrid, transform, updateNodePositions }}
   />
   <Selection
     isVisible={$selectionRectMode === 'nodes'}

packages/svelte/src/lib/components/NodeWrapper/NodeWrapper.svelte

@@ -30,7 +30,7 @@
   let className: string = '';
   export { className as class };
 
-  const { nodes, transform, nodeTypes, updateNodePositions, addSelectedNodes } = useStore();
+  const { nodes, transform, nodeTypes, snapGrid, updateNodePositions, addSelectedNodes } = useStore();
 
   let nodeRef: HTMLDivElement;
   const nodeTypeValid = !!$nodeTypes[type!];
@@ -74,7 +74,7 @@
 
 <!-- svelte-ignore a11y-click-events-have-key-events -->
 <div
-  use:drag={{ nodeId: id, nodes, transform, updateNodePositions }}
+  use:drag={{ nodeId: id, nodes, snapGrid, transform, updateNodePositions }}
   bind:this={nodeRef}
   data-id={id}
   class={cc(['svelte-flow__node', `svelte-flow__node-${type}`, className])}

packages/svelte/src/lib/container/SvelteFlow/SvelteFlow.svelte

@@ -26,6 +26,7 @@
   export let edgeTypes: $$Props['edgeTypes'] = undefined;
   export let selectionKey: $$Props['selectionKey'] = undefined;
   export let selectionMode: $$Props['selectionMode'] = undefined;
+  export let snapGrid: $$Props['snapGrid'] = undefined;
   export let deleteKey: $$Props['deleteKey'] = undefined;
   export let connectionRadius: $$Props['connectionRadius'] = undefined;
   export let connectionLineType: $$Props['connectionLineType'] = undefined;
@@ -56,6 +57,7 @@
       connectionLineType,
       connectionRadius,
       selectionMode,
+      snapGrid,
       isValidConnection
     };
 

packages/svelte/src/lib/container/SvelteFlow/types.ts

@@ -4,7 +4,8 @@ import type {
   NodeOrigin,
   OnConnectStartParams,
   Viewport,
-  SelectionMode
+  SelectionMode,
+  SnapGrid
 } from '@reactflow/system';
 
 import type {
@@ -29,6 +30,7 @@ export type SvelteFlowProps = {
   initialViewport?: Viewport;
   connectionRadius?: number;
   selectionMode?: SelectionMode;
+  snapGrid?: SnapGrid;
 
   class?: string;
   style?: string;

packages/svelte/src/lib/store/initial-store.ts

@@ -6,7 +6,8 @@ import {
   ConnectionMode,
   ConnectionLineType,
   type SelectionRect,
-  type Transform
+  type Transform,
+  type SnapGrid
 } from '@reactflow/system';
 
 import DefaultNode from '$lib/components/nodes/DefaultNode.svelte';
@@ -60,6 +61,7 @@ export const initialStoreState = {
     zoom: null,
     selection: null
   }),
+  snapGrid: writable<SnapGrid | null>(null),
   dragging: writable<boolean>(false),
   selectionRect: writable<SelectionRect | null>(null),
   selectionKeyPressed: writable<boolean>(false),

packages/svelte/src/routes/overview/+page.svelte

@@ -63,7 +63,7 @@
       data: { label: 'Custom Node' },
       position: { x: 150, y: 300 }
     }
-  ]);
+  ], { style: 'width: 125px;' });
 
   const edges = createEdges([
     {
@@ -116,6 +116,7 @@
     maxZoom={2.5}
     selectionMode={SelectionMode.Full}
     initialViewport={{ x: 100, y: 100, zoom: 2 }}
+    snapGrid={[25, 25]}
     on:node:click={(event) => console.log('on node click', event)}
     on:node:mouseenter={(event) => console.log('on node enter', event)} 
     on:node:mouseleave={(event) => console.log('on node leave', event)}
@@ -136,10 +137,6 @@
 </SvelteFlowProvider>
 
 <style>
-  :root {
-    --node-width: 50;
-  }
-
   :global(.svelte-flow .custom-style) {
     background: #ff5050;
     color: white;