1G3topbm User Manual(0) G3topbm User Manual(0)
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6 g3topbm - convert a Group 3 fax file into a PBM image
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10 g3topbm [-kludge] [-reversebits] [-stretch] [-width=pixels |
11 paper_size={A3|A4|A5|A6|B4}] [-stop_error] [g3file]
12 Minimum unique abbreviation of option is acceptable. You may use dou‐
14 ble hyphens instead of single hyphen to denote options. You may use
15 white space in place of the equals sign to separate an option name from
16 its value.
17
20 This program is part of Netpbm(1).
21 g3topbm reads a Group 3 fax file in MH format as input and produces a
23 PBM image as output.
24 g3topbm tolerates various deviations from the standard, so as to
26 recover some of the image if there was a transmission error. One thing
27 it tolerates is lines of varying length. The standard requires all the
28 lines to be the same length; g3topbm makes the output image as wide as
29 the longest line in the input and pads the others on the right. It
30 warns you when it does this.
31 You can use the stop_error option to make g3topbm insist on valid
33 input.
34 There is no Netpbm program that understands the other command fax for‐
36 mats, MR and MMR.
37 There are subformats of TIFF that use the Group 3 fax encodings inside.
39 See tifftopnm.
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43 -kludge
44 Tells g3topbm to ignore the first few lines of the file; some‐
45 times fax files have some junk at the beginning.
46 -reversebits
49 Tells g3topbm to interpret bits least-significant first, instead
50 of the default most-significant first. Apparently some fax
51 modems do it one way and others do it the other way. If you get
52 a whole bunch of 'bad code word' messages, try using this
53 option.
54 -stretch
57 This option tells g3topbm to stretch the image vertically by
58 duplicating each row. This is for the low-quality transmission
59 mode.
60 -width=pixels
63 This option tells g3topbm that the image is supposed to be pix‐
64 els pixels wide. If any line in it is not that size, g3topbm
65 issues a warning or fails, depending on whether you specify
66 -stop_error.
67 You cannot specify both -width and -paper_size.
69 This option was new in Netpbm 10.33 (March 2006).
71 -paper_size={A3,A4,A5,A6,B4}
74 This option tells g3topbm for what size paper this image is sup‐
75 posed to be formatted. g3topbm uses the width of the paper the
76 same way as with the -width option. g3topbm does not use the
77 height of the paper for anything.
78 You cannot specify both -width and -paper_size.
80 This option was new in Netpbm 10.33 (March 2006).
82 -stop_error
85 This option tells g3topbm to fail when it finds a problem in the
86 input. 'Fail' means it terminates with a nonzero status code
87 with the contents of the output file undefined.
88 If you don't specify this option, g3topbm does its best to work
90 around input errors and salvage as much of the image as possible
91 in the output image. It first tries to resynchronize to a later
92 line by searching for the next End Of Line marker, skipping any
93 lines or partial lines in between. It saves the beginning of
94 the line in which it encountered the problem. If the input file
95 ends prematurely, g3topbm produces output containing the lines
96 up to where it encountered the problem.
97 g3topbm issues warning messages when it continues in spite of
99 input errors.
100 This option was new in Netpbm 10.24 (August 2004). Before that,
102 g3topbm always failed when it encountered premature EOF and
103 never failed when it encountered other problems.
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110 pbmtog3(1), tifftopnm(1), pbm(1) faxformats[1m(1)
111netpbm documentation 03 December 2008 G3topbm User Manual(0)