NAME

       PDF::Filter - Abstract superclass for PDF stream filters

SYNOPSIS

           $f = Text::PDF::Filter->new;
           $str = $f->outfilt($str, 1);
           print OUTFILE $str;

           while (read(INFILE, $dat, 4096))
           { $store .= $f->infilt($dat, 0); }
           $store .= $f->infilt("", 1);

DESCRIPTION

       A Filter object contains state information for the process of outputting and inputting
       data through the filter. The precise state information stored is up to the particular
       filter and may range from nothing to whole objects created and destroyed.

       Each filter stores different state information for input and output and thus may handle
       one input filtering process and one output filtering process at the same time.

METHODS

   Text::PDF::Filter->new
       Creates a new filter object with empty state information ready for processing data both
       input and output.

   $dat = $f->infilt($str, $isend)
       Filters from output to input the data. Notice that $isend == 0 implies that there is more
       data to come and so following it $f may contain state information (usually due to the
       break-off point of $str not being tidy). Subsequent calls will incorporate this stored
       state information.

       $isend == 1 implies that there is no more data to follow. The final state of $f will be
       that the state information is empty. Error messages are most likely to occur here since if
       there is required state information to be stored following this data, then that would
       imply an error in the data.

   $str = $f->outfilt($dat, $isend)
       Filter stored data ready for output. Parallels "infilt".

NAME

       Text::PDF::ASCII85Decode - Ascii85 filter for PDF streams. Inherits from Text::PDF::Filter

NAME

       Text::PDF::RunLengthDecode - Run Length encoding filter for PDF streams. Inherits from
       Text::PDF::Filter

NAME

       Text::PDF::ASCIIHexDecode - Ascii Hex encoding (very inefficient) for PDF streams.
       Inherits from Text::PDF::Filter