PBMB Files
Portable Bit Map (binary)
PBMB is a data directory which
contains examples of 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.
The bit '1' means black, '0' means white.
Binary PBM 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:
PBMA,
a data directory which
contains examples of ASCII Portable Bit Map files.
PGMB,
a data directory which
contains examples of binary Portable Gray Map files.
PPMB,
a data directory which
contains examples of binary Portable Pixel Map files.
Reference:
-
the NETPBM homepage.
Sample Files:
-
apollonian_gasket.pbm,
a 600 wide by 600 high image of an Apollonian gasket.
-
apollonian_gasket.png, a PNG image.
-
circle.pbm,
a circle, drawn on a 200 by 200 grid;
-
circle.png,
a PNG version.
-
dla.pbm,
an 800 by 800 image of a structure created by diffusion-limited aggregation.
-
dla.png,
a PNG version.
-
feep.pbm,
the example described above, on a 24 by 7 grid;
-
feep.png,
a PNG version.
-
fool.pbm,
a screenshot from "The Fool's Errand".
-
fool.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.
-
math_emporium.pbm,
a blueprint of the Math Emporium at Virginia Tech, on a 1376 by 1096 grid.
-
math_emporium.png,
a PNG version.
-
pbmlib.pbm, a file created by PBMLIB.
-
pbmlib.png,
a PNG version.
-
scs.pbm,
the letters "SCS", on a grid 136 wide and 82 high.
-
scs.png,
a PNG version.
-
seahorse.pbm,
a silhouette of a sea horse, on a grid 2225 wide and 3601 high.
-
seahorse.png,
a PNG version.
-
sierpinski.pbm,
an image of the Sierpinksi fractal triangle,
on a grid 966 wide and 860 high.
-
sierpinski.png,
a PNG version.
-
washington.pbm,
a silhouette of George Washington, on a grid 305 wide and 400 high.
-
washington.png,
a PNG version.
You can go up one level to
the DATA page.
Last revised on 14 July 2011.