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(1).

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(1), ilbmtoppm(1)

AUTHORS¶

Copyright (C) 1989 by Jef Poskanzer.

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