feat(pkg): Add pathfinding edge pkg to packages dir

packages/pathfinding-edge/src/edge/createGrid.ts

@@ -0,0 +1,70 @@
+import { Grid } from 'pathfinding'
+import { Position } from '@braks/vue-flow'
+import { guaranteeWalkablePath, getNextPointFromPosition } from './guaranteeWalkablePath'
+import { graphToGridPoint } from './pointConversion'
+import { round } from './utils'
+import type { NodeBoundingBox, GraphBoundingBox } from './getBoundingBoxes'
+
+export const gridRatio = 10
+
+export type PointInfo = {
+  x: number
+  y: number
+  position: Position
+}
+
+export const createGrid = (graph: GraphBoundingBox, nodes: NodeBoundingBox[], source: PointInfo, target: PointInfo) => {
+  const { xMin, yMin, width, height } = graph
+
+  // Create a grid representation of the graph box, where each cell is
+  // equivalent to 10x10 pixels on the graph. We'll use this  simplified grid
+  // to do pathfinding.
+  const mapColumns = width / gridRatio
+  const mapRows = height / gridRatio
+  const grid = new Grid(mapColumns, mapRows)
+
+  // Update the grid representation with the space the nodes take up
+  nodes.forEach((node) => {
+    const nodeStart = graphToGridPoint(node.topLeft, xMin, yMin)
+    const nodeEnd = graphToGridPoint(node.bottomRight, xMin, yMin)
+
+    for (let x = nodeStart.x; x < nodeEnd.x; x++) {
+      for (let y = nodeStart.y; y < nodeEnd.y; y++) {
+        grid.setWalkableAt(x, y, false)
+      }
+    }
+  })
+
+  // Convert the starting and ending graph points to grid points
+  const startGrid = graphToGridPoint(
+    {
+      x: round(source.x, gridRatio),
+      y: round(source.y, gridRatio),
+    },
+    xMin,
+    yMin,
+  )
+
+  const endGrid = graphToGridPoint(
+    {
+      x: round(target.x, gridRatio),
+      y: round(target.y, gridRatio),
+    },
+    xMin,
+    yMin,
+  )
+
+  // Guarantee a walkable path between the start and end points, even if the
+  // source or target where covered by another node or by padding
+  const startingNode = grid.getNodeAt(startGrid.x, startGrid.y)
+  guaranteeWalkablePath(grid, startingNode, source.position)
+  const endingNode = grid.getNodeAt(endGrid.x, endGrid.y)
+  guaranteeWalkablePath(grid, endingNode, target.position)
+
+  // Use the next closest points as the start and end points, so
+  // pathfinding does not start too close to the nodes
+  const start = getNextPointFromPosition(startingNode, source.position)
+  const end = getNextPointFromPosition(endingNode, target.position)
+
+  return { grid, start, end }
+}