XBM - X BitMap Format


XBM is a native file format of The X Window System and is used for
storing cursor and icon bitmaps that are used in the X GUI. XBM files
are quite different in that they are actually C language source files
that are created to be read by a C compiler rather than a graphical
display program.

XBM data is typically found in headers (.h files) and are a series of
static unsigned char arrays containing the monochrome pixel
data. There is one array per image stored in the header.

As an example, the following piece of C code is an X BitMap file:

  #define test_width 16
  #define test_height 16
  static unsigned char test_bits[] = {
     0xff, 0xff, 0x01, 0x80, 0xfd, 0xbf, 0x05, 0xa0, 0xf5, 0xaf, 0x15, 0xa8,
     0xd5, 0xab, 0x55, 0xaa, 0x55, 0xaa, 0xd5, 0xab, 0x15, 0xa8, 0xf5, 0xaf,
     0x05, 0xa0, 0xfd, 0xbf, 0x01, 0x80, 0xff, 0xff};

which defines the 16x16 bitmap that looks like:

	################
	#              #
	# ############ #
	# #          # #
	# # ######## # #
	# # #      # # #
	# # # #### # # #
	# # # #  # # # # 
	# # # #  # # # #
	# # # #### # # #
	# # #      # # #
	# # ######## # #
	# #          # #
	# ############ #
	#              #
	################

-----------
XBM was created by the X Consortium as part of the X Window
System. Refer to the /bitmaps directory of the X Window distribution
for examples of XBM files. The central FTP distribution site for X
version 11 is:

  ftp://ftp.x.org

Reference works describing XBM include:

  Xlib-C language X Interface, Gettys, James, and Robert W. Scheiffler,
  Consortium Standard, X Version 11, Release 5, First Revision, August 1991.

  Xlib Programming Manual, Nye, Adrian, third edition, O'Reilly & Associates,
  Inc. Sebastopol, CA, 1992.