ppmtobmp(1) [redhat man page]
ppmtobmp(1) General Commands Manual ppmtobmp(1) NAME
ppmtobmp - convert a portable pixmap into a BMP file SYNOPSIS
ppmtobmp [-windows] [-os2] [-bpp=bits_per_pixel] [ppmfile] DESCRIPTION
Reads a portable pixmap as input. Produces a Microsoft Windows or OS/2 BMP file as output. OPTIONS
All options can be abbreviated to their shortest unique prefix and you can use a double dash in place of the single dash, GNU-style. -windows Tells the program to produce a Microsoft Windows BMP file. (This is the default.) -os2 Tells the program to produce an OS/2 BMP file. (Before August 2000, this was the default). -bpp This determines how many bits per pixel you want the BMP file to contain. Only 1, 4, 8, and 24 are possible. By default, ppmtobmp chooses the smallest number with which it can represent all the colors in the input image. If you specify a number too small to represent all the colors in the input image, ppmtobmp tells you and terminates. You can use ppmquant or ppmdither to reduce the number of colors in the image. NOTES
To get a faithful reproduction of the input image, the maxval of the input image must be 255. If it is something else, ppmtobmp the colors in the BMP file may be slightly different from the colors in the input. Windows icons are not BMP files. Use ppmtowinicon to create those. SEE ALSO
bmptoppm(1), ppmtowinicon(1), ppmquant(1), ppmdither(1), ppm(5) AUTHOR
Copyright (C) 1992 by David W. Sanderson. 13 June 2000 ppmtobmp(1)
Check Out this Related Man Page
ppmquant(1) General Commands Manual ppmquant(1) NAME
ppmquant - quantize the colors in a portable pixmap down to a specified number SYNOPSIS
ppmquant [-floyd|-fs] ncolors [ppmfile] ppmquant [-floyd|-fs] [-nofloyd|-nofs] -mapfile mapfile [ppmfile] All options can be abbreviated to their shortest unique prefix. You may use two hyphens instead of one to designate an option. You may use either white space or equals signs between an option name and its value. DESCRIPTION
pnmquant is a newer, more general program that is backward compatible with ppmquant. ppmquant may be faster, though. Reads a PPM image as input. Chooses ncolors colors to best represent the image, maps the existing colors to the new ones, and writes a PPM image as output. The quantization method is Heckbert's "median cut". Alternately, you can skip the color-choosing step by specifying your own set of colors with the -mapfile option. The mapfile is just a ppm file; it can be any shape, all that matters is the colors in it. For instance, to quantize down to the 8-color IBM TTL color set, you might use: P3 8 1 255 0 0 0 255 0 0 0 255 0 0 0 255 255 255 0 255 0 255 0 255 255 255 255 255 If you want to quantize one image to use the colors in another one, just use the second one as the mapfile. You don't have to reduce it down to only one pixel of each color, just use it as is. If you use a mapfile, the output image has the same maxval as the mapfile. Otherwise, the output maxval is the same as the input maxval, or less in some cases where the quantization process reduces the necessary resolution. The -floyd/-fs option enables a Floyd-Steinberg error diffusion step. Floyd-Steinberg gives vastly better results on images where the unmodified quantization has banding or other artifacts, especially when going to a small number of colors such as the above IBM set. How- ever, it does take substantially more CPU time, so the default is off. -nofloyd/-nofs means not to use the Floyd-Steinberg error diffusion. This is the default. REFERENCES
"Color Image Quantization for Frame Buffer Display" by Paul Heckbert, SIGGRAPH '82 Proceedings, page 297. SEE ALSO
pnmquant(1), ppmquantall(1), pnmdepth(1), ppmdither(1), ppm(5) AUTHOR
Copyright (C) 1989, 1991 by Jef Poskanzer. 12 January 1991 ppmquant(1)