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)
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