code: func Convert(opath, spath string, args ...int) {
  	var mtype = 1
  	if len(args) > 0 {
  		mtype = args[0]
  	}
  
  	// C.CString()
  	bitmap := OpenBitmap(opath)
  	// fmt.Println("a----", bit_map)
  	SaveBitmap(bitmap, spath, mtype)
  }
docs: // Convert convert the bitmap
  //
  // robotgo.Convert(opath, spath string, type int)