jp2_locator::jp2_locator

Creates a null locator, which can be used to open the first JP2 box in any JP2-family source, using jp2_input_box::open. Immediately after construction, the is_null function returns true. There are two ways to obtain another locator, as follows:

• Invoke jp2_input_box::get_locator on an existing open box.
• Use set_file_pos to set the locator to reference an absolute location in an original file (works even if the file is being served up incrementally in an unpredictable order).