PDL::IO::Pnm--3pm

Pnm(3pm)              User Contributed Perl Documentation             Pnm(3pm)



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
       rpnm

       Read a pnm (portable bitmap/pixmap, pbm/ppm) file into a piddle.

       Reads a file 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-com-
       ponent 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.

           $im = rpnm $file;

         $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.

       Writes data in a pdl into pnm format (ascii or raw) (magic numbers
       P1-P6).  The $format is required (normally produced by wpic) and rou-
       tine just checks if data is compatible with that format. All conver-
       sions should already have been done. If possible, usage of wpic is pre-
       ferred. 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 for-
       mats consult appropriate manpages that come with the netpbm/pbmplus
       packages.

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

BUGS
       The stderr of the converters is redirected to a file. The filename is
       currently generated in a probably non-portable way. A method that
       avoids a file (and is portable) would be prefered.

       "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 for-
       mats (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 AT auckland.nz>
       All rights reserved. There is no warranty. You are allowed to redis-
       tribute 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.

FUNCTIONS
       pnminraw

         Signature: (type(); byte+ [o] im(m,n); int ms => m; int ns => n;
                               int isbin; char* fd)

       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").

       pnminascii

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

       Read in an ascii pnm file.

       pnmout

         Signature: (a(m); int israw; int isbin; char *fd)

       Write a line of pnm data.

       This function is implemented this way so that threading works natu-
       rally.



perl v5.8.8                       2007-01-14                          Pnm(3pm)