Netpbm
Netpbm is an open source package of graphics programs and a programming library, used mainly in the Unix world. The latest stable version is 10.26.25 (released 19 February 2006).
File formats and programs
Netpbm defines a set of graphics formats called the netpbm formats:
- The portable pixmap/greymap/bitmap formats PPM, PGM, PBM. They are collectively referred to as PNM.
- The more sophisticated PAM format.
Netpbm contains over 220 separate programs in the package, most of which have "pbm", "pgm", "ppm", "pam", or "pnm" in their names. For example, you might use pamscale to shrink an image by 10%, pamcomp to overlay one image on top of another, pbmtext to create an image of text or reduce the number of colors in an image with pnmquant.
The Netpbm programs are frequently used as intermediates to convert between obscure formats. For instance, there may be no tool to convert an X11 window dump (XWD format) directly to a Macintosh PICT file, but by running xwdtopnm, then ppmtopict, this can be achieved. (Tools which say that they output PNM may output PPM, PGM or PBM. Tools importing PNM will read any of the three formats.)
