convertPictureToImage method
Converts the underlying ui.Picture to a ui.Image.
If this TilePicture already contains an image, that image is returned directly.
Implementation
Future<ui.Image> convertPictureToImage() async {
if (_image != null) return _image;
return await _picture!.toImage(MapsforgeSettingsMgr().tileSize.round(), MapsforgeSettingsMgr().tileSize.round());
}