How to apply parallax image to android desktop

Question

I have achieved the parallax effect and would like to install it on the desktop, but "wallpaper manager" only works with images without functions. How can I display functions on the desktop?

Instructions "wallpaper manager":

    String path = "/path/to/file/on/disk";
int location = WallpaperManager.HOME_SCREEN; // or location = WallpaperManager.LOCK_SCREEN;
String result;
try {
  result = await WallpaperManager.setWallpaperFromFile(path, location);
} on PlatformException {
  result = 'Failed to get wallpaper.';
}