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:
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.
|
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
AUTHORS
Copyright (C) 1989 by Jef Poskanzer.
Modified October 1993 by Ingo Wilken (Ingo.Wilken@informatik.uni-oldenburg.de)