ppmtoilbm - convert a PPM image into an ILBM file



[-maxplanes|-mp N]

[-fixplanes|-fp N]


[{-dcbits|-dcplanes} r g b]

[ -normal|-hamif|-hamforce|-24if|-24force| -dcif|-dcforce|-cmaponly ]



[-cmethod type]

[-map ppmfile]




This program is part of Netpbm(1)

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

o Normal ILBMs with 1-16 planes

o Amiga HAM with 3-16 planes

o 24 bit

o Color map (BMHD + CMAP chunk only, nPlanes = 0)

o 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 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.

 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.

 Write a colormap file: only BMHD and CMAP chunks, no BODY chunk, nPlanes = 0.

 See the -compress option.


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.


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


ppm(5) , ilbmtoppm(1)


Copyright (C) 1989 by Jef Poskanzer.

Modified October 1993 by Ingo Wilken (

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