Pnm(m) User Contributed Perl Documentation Pnm(m) 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-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. $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 dat- acube). 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 pro- duced by wpic) and routine just checks if data is compati- ble with that format. All conversions should already have been done. If possible, usage of wpic is preferred. Cur- rently 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. $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 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@auck- land.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 COPY- ING 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(a); int israw; int isbin; char *fd) Write a line of pnm data. This function is implemented this way so that threading works naturally. perl v5.6.1 2002-04-08 Pnm(m)