dxf/src/applyTransforms.js

DXF parser for node/browser

/**
 * Apply the transforms to the polyline.
 *
 * @param polyline the polyline
 * @param transform the transforms array
 * @returns the transformed polyline
 */
export default (polyline, transforms) => {
  transforms.forEach((transform) => {
    polyline = polyline.map(function (p) {
      // Use a copy to avoid side effects
      let p2 = [p[0], p[1]]
      if (transform.scaleX) {
        p2[0] = p2[0] * transform.scaleX
      }
      if (transform.scaleY) {
        p2[1] = p2[1] * transform.scaleY
      }
      if (transform.rotation) {
        const angle = (transform.rotation / 180) * Math.PI
        p2 = [
          p2[0] * Math.cos(angle) - p2[1] * Math.sin(angle),
          p2[1] * Math.cos(angle) + p2[0] * Math.sin(angle),
        ]
      }
      if (transform.x) {
        p2[0] = p2[0] + transform.x
      }
      if (transform.y) {
        p2[1] = p2[1] + transform.y
      }
      // Observed once in a sample DXF - some cad applications
      // use negative extruxion Z for flipping
      if (transform.extrusionZ === -1) {
        p2[0] = -p2[0]
      }
      return p2
    })
  })
  return polyline
}