public static async unowned PixbufFormat? get_file_info_async (string filename, Cancellable? cancellable, out int width, out int height) throws Error
Asynchronously parses an image file far enough to determine its format and size.
For more details see get_file_info, which is the synchronous version of this function.
When the operation is finished,
callback will be called in the main thread. You can then call
get_file_info_async.end to get the result of the operation.
The name of the file to identify
optional `GCancellable` object, `NULL` to ignore
a `GAsyncReadyCallback` to call when the file info is available
the data to pass to the callback function