feat(core): add useGetPointerPosition composable

Signed-off-by: braks <78412429+bcakmakoglu@users.noreply.github.com>

packages/core/src/composables/useGetPointerPosition.ts

@@ -0,0 +1,28 @@
+import type { UseDragEvent } from './useDrag'
+import type { SnapGrid } from '~/types'
+
+export function useGetPointerPosition() {
+  const { viewport, snapGrid: globalSnapGrid, snapToGrid } = useVueFlow()
+
+  const hasSnapGrid = (sg?: SnapGrid) => (sg ?? snapToGrid ? globalSnapGrid : undefined)
+
+  // returns the pointer position projected to the RF coordinate system
+  return ({ sourceEvent }: UseDragEvent, snapGrid?: SnapGrid) => {
+    const currentSnapGrid = unref(hasSnapGrid(snapGrid || globalSnapGrid.value))
+
+    const x = sourceEvent.touches ? sourceEvent.touches[0].clientX : sourceEvent.clientX
+    const y = sourceEvent.touches ? sourceEvent.touches[0].clientY : sourceEvent.clientY
+
+    const pointerPos = {
+      x: (x - viewport.value.x) / viewport.value.zoom,
+      y: (y - viewport.value.y) / viewport.value.zoom,
+    }
+
+    // we need the snapped position in order to be able to skip unnecessary drag events
+    return {
+      xSnapped: currentSnapGrid ? currentSnapGrid[0] * Math.round(pointerPos.x / currentSnapGrid[0]) : pointerPos.x,
+      ySnapped: currentSnapGrid ? currentSnapGrid[1] * Math.round(pointerPos.y / currentSnapGrid[1]) : pointerPos.y,
+      ...pointerPos,
+    }
+  }
+}