PGMA_IO is a FORTRAN77 library which reads and writes files in the ASCII Portable Gray Map (PGM) format for 2D grayscale graphics information.
There are many graphics programs, such as XV and GIMP, that can display images in this format, or translate them to other formats such as BMP, GIF, JPEG, MacPaint, X Window, and so on.
The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.
PGMA_IO is available in a C version and a C++ version and a FORTRAN77 version and a FORTRAN90 version and a MATLAB version.
PBMA_IO, a FORTRAN90 library which handles the ASCII Portable Bit Map (PBM) format.
PGMA, a data file directory which contains examples of ASCII Portable Gray Map (PGM) files.
PGMA_TO_PGMB, a C++ program which converts an ASCII Portable Gray Map (PGM) file to a binary PGM file.
PGMB_TO_PGMA, a C++ program which converts a binary Portable Gray Map (PGM) file to an ASCII PGM file.
PPMA_IO, a FORTRAN90 library which handles the ASCII Portable Pixel Map (PPM) format.
You can go up one level to the FORTRAN90 source codes.