oracular (3) PDL::IO::Pnm.3pm.gz

NAME

       PDL::IO::Pnm -- pnm format I/O for PDL

SYNOPSIS

         use PDL::IO::Pnm;
         $im = wpnm $pdl, $file, $format[, $raw];
         rpnm $stack->slice(':,:,:,(0)'),"PDL.ppm";

DESCRIPTION

       pnm I/O for PDL.

FUNCTIONS

   pnminraw
         Signature: (type(); byte+ [o] im(m,n); byte [t] buf(llen); int ms => m; int ns => n;
                               int isbin; PerlIO *fp)

       Read in a raw pnm file.

       read a raw pnm file. The "type" argument is only there to determine the type of the operation when
       creating "im" or trigger the appropriate type conversion (maybe we want a byte+ here so that "im" follows
       strictly the type of "type").

       pnminraw does not process bad values.  It will set the bad-value flag of all output ndarrays if the flag
       is set for any of the input ndarrays.

   pnminascii
         Signature: (type(); byte+ [o] im(m,n); int ms => m; int ns => n;
                               int format; PerlIO *fp)

       Read in an ascii pnm file.

       pnminascii does not process bad values.  It will set the bad-value flag of all output ndarrays if the
       flag is set for any of the input ndarrays.

   pnmout
         Signature: (a(m); int israw; int isbin; PerlIO *fp)

       Write a line of pnm data.

       This function is implemented this way so that broadcasting works naturally.

       pnmout does not process bad values.  It will set the bad-value flag of all output ndarrays if the flag is
       set for any of the input ndarrays.

   rpnm
       Read a pnm (portable bitmap/pixmap, pbm/ppm) file into an ndarray.

         Usage:  $im = rpnm $file;

       Reads a file (or open file-handle) in pnm format (ascii or raw) into a pdl (magic numbers P1-P6).  Based
       on the input format it returns pdls with arrays of size (width,height) if binary or grey value data (pbm
       and pgm) or (3,width,height) if rgb data (ppm). This also means for a palette image that the distinction
       between an image and its lookup table is lost which can be a problem in cases (but can hardly be avoided
       when using netpbm/pbmplus).  Datatype is dependent on the maximum grey/color-component value (for raw and
       binary formats always PDL_B). rpnm tries to read chopped files by zero padding the missing data (well it
       currently doesn't, it barfs; I'll probably fix it when it becomes a problem for me ;). You can also read
       directly into an existing pdl that has to have the right size(!). This can come in handy when you want to
       read a sequence of images into a datacube.

       For details about the formats see appropriate manpages that come with the netpbm/pbmplus packages.

         $stack = zeroes(byte,3,500,300,4);
         rpnm $stack->slice(':,:,:,(0)'),"PDL.ppm";

       reads an rgb image (that had better be of size (500,300)) into the first plane of a 3D RGB datacube (=4D
       pdl datacube). You can also do inplace transpose/inversion that way.

   wpnm
       Write a pnm (portable bitmap/pixmap, pbm/ppm) file into a file or open file-handle.

         Usage:  $im = wpnm $pdl, $file, $format[, $raw];

       Writes data in a pdl into pnm format (ascii or raw) (magic numbers P1-P6).  The $format is required
       (normally produced by wpic) and routine just checks if data is compatible with that format. All
       conversions should already have been done. If possible, usage of wpic is preferred. Currently RAW format
       is chosen if compliant with range of input data. Explicit control of ASCII/RAW is possible through the
       optional $raw argument. If RAW is set to zero it will enforce ASCII mode. Enforcing RAW is somewhat
       meaningless as the routine will always try to write RAW format if the data range allows (but maybe it
       should reduce to a RAW supported type when RAW == 'RAW'?). For details about the formats consult
       appropriate manpages that come with the netpbm/pbmplus packages.

BUGS

       "rpnm" currently relies on the fact that the header is separated from the image data by a newline. This
       is not required by the p[bgp]m formats (in fact any whitespace is allowed) but most of the pnm writers
       seem to comply with that. Truncated files are currently treated ungracefully ("rpnm" just barfs).

AUTHOR

       Copyright (C) 1996,1997 Christian Soeller <c.soeller@auckland.ac.nz> All rights reserved. There is no
       warranty. You are allowed to redistribute this software / documentation under certain conditions. For
       details, see the file COPYING in the PDL distribution. If this file is separated from the PDL
       distribution, the copyright notice should be included in the file.