Man page 1 : pnmtorle

pnmtorle - convert a Netpbm image file into an RLE image file.

pnmtorle [

-h ] [

-v ] [

-a ] [ -o outfile ] [ pnmfile]

This program converts Netpbm image files into Utah

R RLE (5) image files. You can include an alpha mask. If the input is a multiple image file, the output consists of several concatenated RLE images.

The RLE file will contain either a three channel color image (24 bits) or a single channel grayscale image (8 bits) depending upon the pnm file depth. If a converted ppm is displayed on an 8 bit display, the image must be dithered. In order to produce a better looking image (on 8 bit displays), it is recommended that the image be quantizing (to 8 bit mapped color) prior to its display. This may be done by piping the output of this program into the Utah

R mcut (1) or

R rlequant (1) utilities. An example of this is shown later.

-v

    This option will cause pnmtorle to operate in verbose mode. The header information is written to "stderr". Actually, there is not much header information stored in a Netpbm file, so this information is minimal.

-h

    This option allows the header of the Netpbm image to be dumped to "stderr" without converting the file. It is equivalent to using the -v option except that no file conversion takes place.

-a

    This option causes pnmtorle to include an alpha channel in the output image. The alpha channel is based on the image: Wherever a pixel is black, the corresponding alpha value is transparent. Everywhere else, the alpha value is fully opaque.

• -o outfile
      If specified, the output will be written to this file. If outfileis "-", or if it is not specified, the output will be written to the standard output stream.
• pnmfile
      The name of the Netpbm image data file to be converted. If not specified, standard input is assumed.

• pnmtorle -v file.ppm -o file.rle
      While running in verbose mode, convert file.ppm to RLE format and store resulting data in file.rle.
• pnmtorle -h file.pgm
      Dump the header information of the Netpbm file called file.pgm.

R rletopnm (1),

R urt (1),

R RLE (5).

Wes Barris
Army High Performance Computing Research Center (AHPCRC)
Minnesota Supercomputer Center, Inc.