ilbmtoppm
Updated: 04 July 2026
Table Of Contents
NAME
ilbmtoppm - convert an ILBM file into a PPM image
SYNOPSIS
ilbmtoppm
[-ignore<chunkID>]
[
-isham |
-isehb |
-isdeep
]
[-cmaponly]
[-adjustcolors]
[-transparent color]
[-maskfile filename
[-verbose]
[ILBMfile]
DESCRIPTION
This program is part of Netpbm.
ilbmtoppm reads an IFF FORM file as input and produces a PPM
image as output. ilbmtoppm can handle the following IFF FORM
types:
It can handle the following ILBM types:
- Normal ILBMs with 1-16 planes.
- Amiga Extra_Halfbrite (EHB)
- Amiga HAM with 3-16 planes.
- 24 bit.
- Multiplatte (normal or HAM) pictures.
- Color map (BMHD + CMAP chunk only, nPlanes = 0).
- Unofficial direct color. 1-16 planes for each color component.
ilbmtoppm uses these ILBM chunks: BMHD, CMAP, CAMG (only HAM
& EHB flags used), PCHG, BODY unofficial DCOL chunk to identify
direct color ILBM. It ignores these chunks: GRAB, DEST, SPRT, CRNG,
CCRT, CLUT, DPPV, DRNG, EPSF. It ignores, but displays in verbose
mode, these: NAME, AUTH, (c), ANNO, DPI. It skips chunks whose type
it doesn't recognize.
OPTIONS
In addition to the options common to all programs based on libnetpbm
(most notably -quiet, see
Common Options), ilbmtoppm recognizes the following
command line options:
- -transparent color
- This is the color that should "show through" in places where
the image is transparent.
color is like the argument of
the pnm_parsecolor() library routine.
- -verbose
- Give some information about the ILBM file.
- -ignore chunkID
- Skip a chunk. chunkID is the 4-letter IFF chunk identifier
of the chunk to be skipped.
- -isham
- Treat the input file as a HAM picture, even if The CAMG chunk does not say
it is one (or if there is no CAMG chunk).
- -isehb
- Treat the input file as an Extra_Halfbrite picture, even if the CAMG chunk
does not say it is one (or if there is no CAMG chunk).
- -isdeep
- Treat the input file as a deep ILBM image, if it has the right number of
planes to be one. If it does not (i.e. the number of planes is not a multiple
of 3), this option has no effect other than an informational message telling
you it is being ignored.
If the input file is not ILBM, this option has no effect.
- -maskfile filename
- This names a file for ilbmtoppm to create with the image's
transparency mask. The mask file is a PBM image which maps to the input image
with white pixels representing transparent pixels in the image and black
pixels representing opaque pixels.
If you don't specify this, or the image does not contain transparency
information, ilbmtoppm does not create a mask file.
- -cmaponly
- With this option, ilbmtoppm generates a PPM of the ILBM's color
map, not the image itself.
ilbmtoppm does the same thing even without -cmaponly if the
ILBM is a pure color map stream (it has a bitmap header with an nplanes
value of zero or has no BODY chunk.
- -adjustcolors
- If all colors in the CMAP have a value of less then 16, ilbmtoppm
assumes a 4-bit colormap and gives a warning. With this option the
colormap is scaled to 8 bits.
LIMITATIONS
The multipalette PCHG BigLineChanges and Huffman decompression code
is untested.
REFERENCES
Amiga ROM Kernel Reference Manual - Devices (3rd Ed.)
Addison Wesley, ISBN 0-201-56775-X
SEE ALSO
ppmtoilbm,
ppm
AUTHORS
Copyright (C) 1989 by Jef Poskanzer.
Modified October 1993 by Ingo Wilken (Ingo.Wilken@informatik.uni-oldenburg.de)
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