array.py 文件源码

def truncate(self, size=None):
        """
        Resize the stream to the given size in bytes (or the current position
        if size is not specified). This resizing can extend or reduce the
        current file size.  The new file size is returned.

        In prior versions of picamera, truncation also changed the position of
        the stream (because prior versions of these stream classes were
        non-seekable). This functionality is now deprecated; scripts should
        use :meth:`~io.IOBase.seek` and :meth:`truncate` as one would with
        regular :class:`~io.BytesIO` instances.
        """
        if size is not None:
            warnings.warn(
                PiCameraDeprecated(
                    'This method changes the position of the stream to the '
                    'truncated length; this is deprecated functionality and '
                    'you should not rely on it (seek before or after truncate '
                    'to ensure position is consistent)'))
        super(PiArrayOutput, self).truncate(size)
        if size is not None:
            self.seek(size)