1Ppmtoilbm User Manual(0) Ppmtoilbm User Manual(0)
2
6 ppmtoilbm - convert a PPM image into an ILBM file
7
10 ppmtoilbm
11 [-maxplanes|-mp N]
13 [-fixplanes|-fp N]
15 [-ham6|-ham8]
17 [{-dcbits|-dcplanes} r g b]
19 [ -normal|-hamif|-hamforce|-24if|-24force| -dcif|-dcforce|-cmaponly ]
21 [-ecs|-aga]
23 [-compress|-nocompress]
25 [-cmethod type]
27 [-map ppmfile]
29 [ppmfile]
31
35 This program is part of Netpbm(1).
36 ppmtoilbm reads a PPM image as input. Produces an ILBM file as output.
38 ppmtoilbm understands the following ILBM types:
39 • Normal ILBMs with 1-16 planes
44 • Amiga HAM with 3-16 planes
47 • 24 bit
50 • Color map (BMHD + CMAP chunk only, nPlanes = 0)
53 • Unofficial direct color. 1-16 planes for each color component.
56 Chunks written: BMHD, CMAP, CAMG (only for HAM), BODY (not for colormap
60 files) unofficial DCOL chunk for direct color ILBM.
61
65 In addition to the options common to all programs based on libnetpbm
66 (most notably -quiet, see
67 Common Options ⟨index.html#commonoptions⟩ ), ppmtoilbm recognizes the
68 following command line options:
69 Options marked with (*) can be prefixed with a "no", e.g. "-nohamif".
71 All options can be abbreviated to their shortest unique prefix.
72 -maxplanes | -mp n
76 (default 5, minimum 1, maximum 16) Maximum planes to write in a
77 normal ILBM. If the image does not fit into <n> planes, ppm‐
78 toilbm writes a HAM file (if -hamif is used), a 24bit file (if
79 -24if is used) or a direct color file (if -dcif is used) or
80 aborts with an error.
81 -fixplanes | -fp b
84 (min 1, max 16) If a normal ILBM is written, it will have ex‐
85 actly <n> planes.
86 -hambits | -hamplanes n
89 (default 6, min 3, max 16) Select number of planes for HAM pic‐
90 ture. The current Amiga hardware understands 6 and 8 planes, so
91 for now you should only use this values.
92 -normal
95 Turns off -hamif/-24if/-dcif, -hamforce/-24force/-dcforce and
96 -cmaponly. Also sets compression type to byterun1.
97 This is the default.
99 -hamif (*)
102 -24if (*)
104 -dcif (*)
106 Write a HAM/24bit/direct color file if the image does not fit
107 into <maxplanes> planes.
108 -hamforce (*)
111 -24force (*)
113 -dcforce (*)
115 Write a HAM/24bit/direct color file.
116 -dcbits r g b
119 -dcplanes r g b
121 (default 5, min 1, max 16). Select number of bits for red,
122 green and blue in a direct color ILBM.
123 -ecs Shortcut for: -hamplanes 6 -maxplanes 5
126 This is the default.
128 -aga Shortcut for: -hamplanes 8 -maxplanes 8
131 -ham6 Shortcut for: -hamplanes 6 -hamforce
134 -ham8 Shortcut for: -hamplanes 8 -hamforce
137 -compress (*)
140 This is the default. Compress the BODY chunk. The default com‐
141 pression method is byterun1. Compression requires building the
142 ILBM image in memory; turning compression off allows stream-
143 writing of the image, but the resulting file will usually be 30%
144 to 50% larger. Another alternative is the -savemem option, this
145 will keep memory requirements for compression at a minimum, but
146 is very slow.
147 -cmethod none|byterun1
150 This option does the same thing as -compress.
151 -map ppmfile
154 Write a normal ILBM using the colors in <ppmfile> as the col‐
155 ormap. The colormap file also determines the number of planes;
156 -maxplanes and -fixplanes are ignored.
157 -cmaponly
160 Write a colormap file: only BMHD and CMAP chunks, no BODY chunk,
161 nPlanes = 0.
162 -savemem
165 See the -compress option.
166
172 HAM pictures will always get a grayscale colormap; a real color selec‐
173 tion algorithm might give better results. On the other hand, this al‐
174 lows row-by-row operation on HAM images, and all HAM images of the same
175 depth (no. of planes) share a common colormap, which is useful for
176 building HAM animations.
177
180 Amiga ROM Kernel Reference Manual - Devices (3rd Ed.) Addison Wesley,
181 ISBN 0-201-56775-X
182
186 ppm(1), ilbmtoppm(1)
187
191 For about a year in 1993-1994, there was a -savemem option.
192 There used to be a -floyd (aka -fs) option that was supposed
194 to cause images to be dithered so that a larger number of colors in
195 the PPM
196 input could be represented in a smaller number of colors in the ILBM
197 output.
198 But it was never documented. Furthermore, developers discovered in
199 January
200 2022 that the code for this was nonfunctional because of defects, and
201 had
202 been for a very long time and maybe always. Finally,, this functions
203 is not
204 appropriate in the Netpbm philosophy, because dithering should be
205 done by a
206 separate dithering program, not a format conversion program. Indeed,
207 the programs ppmdither, pnmquant, and pnmremap can do
208 this.
209 Therefore, since Netpbm 10.98 (March 2022), the dithering code has not
211 been
212 in the program and any attempt to use the options fails with a simple
213 invalid option message. But the -nofloyd and -nofs options
214 remain, doing nothing as they were designed to do, and still not doc‐
215 umented.
216 This is just in case something uses those options, since the cost of
217 maintaining them is so small.
218
222 Copyright (C) 1989 by Jef Poskanzer.
223 Modified October 1993 by Ingo Wilken (Ingo.Wilken@informatik.uni-olden‐
225 burg.de)
226
228 This manual page was generated by the Netpbm tool 'makeman' from HTML
229 source. The master documentation is at
230 http://netpbm.sourceforge.net/doc/ppmtoilbm.html
232netpbm documentation 15 January 2022 Ppmtoilbm User Manual(0)