pnm

Various pnm* tools for PNM image manipulation.

PNM (Portable Anymap) is an umbrella term for the Netpbm image format family: PBM (bitmap, black and white), PGM (graymap, grayscale), and PPM (pixmap, color). These formats use simple, human-readable headers followed by pixel data in either ASCII or binary encoding.PNM serves as the intermediate format in the Netpbm toolkit, where images are converted to PNM, processed with various pnm* tools, and then converted to the desired output format. The simplicity of PNM makes it easy to generate and parse programmatically.

PNM formats include:- PBM (bitmap)- PGM (grayscale)- PPM (color)Part of Netpbm toolkit.

PNM files are uncompressed and can be very large compared to formats like PNG or JPEG. The more general term "Netpbm format" also includes PAM. No official MIME type is registered; image/x-portable-anymap is used by convention.

PNM was created as part of the Netpbm project, originally derived from Jef Poskanzer's Pbmplus toolkit (1988). Netpbm continues to be maintained as an open-source package for portable image manipulation.

pbm(5), pgm(5), ppm(5), netpbm(1)