Ppmtoilbm User Manual

# ppmtoilbm

Updated: 31 October 1993
Table Of Contents

## NAME

ppmtoilbm - convert a PPM image into an ILBM file

## SYNOPSIS

ppmtoilbm [-maxplanes|-mp N] [-fixplanes|-fp N] [-ham6|-ham8] [{-dcbits|-dcplanes} r g b] [ -normal|-hamif|-hamforce|-24if|-24force| -dcif|-dcforce|-cmaponly ] [-ecs|-aga] [-compress|-nocompress] [-cmethod type] [-map ppmfile] [-savemem] [ppmfile]

## DESCRIPTION

This program is part of Netpbm.

ppmtoilbm reads a PPM image as input. Produces an ILBM file as output. ppmtoilbm understands the following ILBM types:

- Normal ILBMs with 1-16 planes
- Amiga HAM with 3-16 planes
- 24 bit
- Color map (BMHD + CMAP chunk only, nPlanes = 0)
- Unofficial direct color. 1-16 planes for each color component.

Chunks written: BMHD, CMAP, CAMG (only for HAM), BODY (not for colormap files) unofficial DCOL chunk for direct color ILBM.

## OPTIONS

Options marked with (*) can be prefixed with a "no", e.g. "-nohamif". All options can be abbreviated to their shortest unique prefix.

-maxplanes | -mp n
  (default 5, minimum 1, maximum 16) Maximum planes to write in a normal ILBM. If the image does not fit into <n> planes, ppmtoilbm writes a HAM file (if -hamif is used), a 24bit file (if -24if is used) or a direct color file (if -dcif is used) or aborts with an error.
-fixplanes | -fp b
  (min 1, max 16) If a normal ILBM is written, it will have exactly <n> planes.
-hambits | -hamplanes n
  (default 6, min 3, max 16) Select number of planes for HAM picture. The current Amiga hardware supports 6 and 8 planes, so for now you should only use this values.
-normal
  Turns off -hamif/-24if/-dcif, -hamforce/-24force/-dcforce and -cmaponly. Also sets compression type to byterun1.

  This is the default.

-hamif (*)
-24if (*)
-dcif (*)
  Write a HAM/24bit/direct color file if the image does not fit into <maxplanes> planes.
-hamforce (*)
-24force (*)
-dcforce (*)
  Write a HAM/24bit/direct color file.
-dcbits r g b
-dcplanes r g b
  (default 5, min 1, max 16). Select number of bits for red, green and blue in a direct color ILBM.
-ecs
  Shortcut for: -hamplanes 6 -maxplanes 5

  This is the default.

-aga
  Shortcut for: -hamplanes 8 -maxplanes 8
-ham6
  Shortcut for: -hamplanes 6 -hamforce
-ham8
  Shortcut for: -hamplanes 8 -hamforce
-compress (*)
  This is the default.
  Compress the BODY chunk. The default compression method is byterun1. Compression requires building the ILBM image in memory; turning compression off allows stream-writing of the image, but the resulting file will usually be 30% to 50% larger. Another alternative is the -savemem option, this will keep memory requirements for compression at a minimum, but is very slow.
-cmethod none|byterun1
  This option does the same thing as -compress.
-map ppmfile
  Write a normal ILBM using the colors in <ppmfile> as the colormap. The colormap file also determines the number of planes, a -maxplanes or -fixplanes option is ignored.
-cmaponly
  Write a colormap file: only BMHD and CMAP chunks, no BODY chunk, nPlanes = 0.
-savemem
  See the -compress option.

## LIMITATIONS

HAM pictures will always get a grayscale colormap; a real color selection algorithm might give better results. On the other hand, this allows row-by-row operation on HAM images, and all HAM images of the same depth (no. of planes) share a common colormap, which is useful for building HAM animations.

## REFERENCES

Amiga ROM Kernel Reference Manual - Devices (3rd Ed.)
Addison Wesley, ISBN 0-201-56775-X

## SEE ALSO

ppm, ilbmtoppm

## AUTHORS

Copyright (C) 1989 by Jef Poskanzer.

Modified October 1993 by Ingo Wilken (Ingo.Wilken@informatik.uni-oldenburg.de)

## Table Of Contents

- NAME
- SYNOPSIS
- DESCRIPTION
- OPTIONS
- LIMITATIONS
- REFERENCES
- SEE ALSO
- AUTHORS