PBMB Files
Portable Bit Map (binary)

PBMB is the binary version of the portable bitmap PBM format, a lowest common denominator monochrome file format. It was originally designed to make it reasonable to mail bitmaps between different types of machines. Now it serves as the common language of a large family of bitmap conversion filters. The definition is as follows:

• the typical file extension is ".pbm", but an extension of ".pnm" is also occasionally used.
• A "magic number" for identifying the file type. A binary PBMB file's magic number is the two characters "P4".
• Whitespace (blanks, TABs, CRs, LFs).
• A width, formatted as ASCII characters in decimal.
• Whitespace.
• A height, again in ASCII decimal.
• Whitespace. (It may be the case that this is required to be a single character of whitespace, usually a new line.)
• Width * height bits, stored 8 bits per byte, high bit first and low bit last, starting at the top-left corner of the bitmap, proceeding in normal English reading order.

PBMB File Characteristics:

• binary
• black and white
• 2D
• No compression
• 1 image

Licensing:

The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.

Related Data and Programs:

The PBMA data directory describes ASCII Portable Bit Map files.

The PGMB data directory describes binary Portable Gray Map files.

The PPMB data directory describes binary Portable Pixel Map files.

Reference:

1. the NETPBM homepage.

Programs to create a PBMB file include:

• The gnuplot command "set terminal pbm monochrome".
• The mathematica command DISPLAY;

Programs and routines to read a PBMB file:

• MATLAB can read a PBMB file with a command like A=imread('file','PBM').
• pbmlib, FORTRAN90 routines.
• pbmb_io C++ routines
• The Visual Toolkit routine vtkPNMReader can read a binary PBM file into VTK.

Programs and routines to write a PBMB file:

• MATHEMATICA includes an Export[filename,object] command that can save a graphics object as a binary PBM file.
• MATLAB can write a PBMB file with a command like imwrite(a,'filename','PBM').
• pbmlib, FORTRAN90 routines.
• pbmb_io C++ routines
• The Visual Toolkit routine vtkPNMWriter can write a VTK image to a binary PBM file.

Programs to display a PBMB file:

• The AVS module read_any_image can read a PBMB file;
• GIMP, the GNU Image Manipulation Program, can display a PBMB file.
• The ImageVision program imgview can display a PBMB file.
• MATLAB can display a PBMB file, once it is read in, with a command like image(A).
• xv can display a PBMB file.

Programs to convert a PBMB file to another format:

• The ImageMagick, program convert can convert a PBMB file to BMP, CGM, EPS, FIG, FITS, GIF, JPG, PBM, PDF, PGM, PNG, PNM, PPM, PS, RGB, TIF, XBM or XPM format.
• GIMP, the GNU Image Manipulation Program, can read a PBMB file and write out a copy in a variety of formats.
• The NETPBM program PBMTOASCII can read a PBMB file and write out it out as ASCII graphics.
• xv can read a PBMB file and write out a copy in BMP, FIT, GIF, JPG, PGM, PPM, RGB or TIF format.

Programs to convert a file to PBMB format:

• The ImageMagick, program convert can convert a BMP, CGM, EPS, FIG, FITS, GIF, JPG, PBM, PDF, PGM, PNG, PNM, PPM, PS, RGB, TIF, XBM or XPM file to PBMB format.
• GIMP, the GNU Image Manipulation Program, can read a file in a variety of formats, and write it out as a PBMB file.
• xv can read a file in a BMP, FIT, GIF, JPG, PGM, PPM, RGB or TIF format, and write it out as a PBMB file.

Sample PBMB Files:

• circle.pbm, a circle, drawn on a 200 by 200 grid;
• circle.png, a PNG version.
• feep.pbm, the example described above, on a 24 by 7 grid;
• feep.png, a PNG version.
• gerrymander.pbm, an image of the "Gerry-mander", on a 303 by 325 grid;
• gerrymander.png, a PNG version.
• letter_a.pbm, a capital A, using a 25 by 25 grid.
• letter_a.png, a PNG version.
• pbmlib.pbm, a file created by PBMLIB.
• pbmlib.png, a PNG version.
• scs.pbm, the letters "SCS", on a 136 by 82 grid;
• scs.png, a PNG version.

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