1DDJVU(1) DjVuLibre-3.5 DDJVU(1)
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6 ddjvu - Command line DjVu decoder.
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10 ddjvu -format=fmt [options] [djvufile] [outputfile]
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14 This program decodes DjVu file djvufile, produces a raw image, and
15 saves it into file outputfile.
16 The DjVu data is read from the standard input when argument djvufile is
18 not specified or when it is equal to a single dash. Similarly, the
19 output data is written to the standard output when argument outputfile
20 is not specified or equal to a single dash.
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24 -format=fmt
25 Specify the output file formats. The recognized file formats
26 are pbm, pgm, ppm, pnm, tiff, and rle.
27 * Formats pbm, pgm, and ppm respectively produce a Portable
29 Bitmap (PBM), Portable Graymap (PGM), or Portable Pixmap
30 (PGM) file. Format pnm produces either a PBM, a PGM, or a
31 PPM output file according to the color nature of the output
32 image.
33 * Format tiff produces a Tagged Image Format (TIFF) file. Com‐
35 mand tiffcp(1) and tiffsplit(1) are useful for manipulating
36 the resulting TIFF files.
37 * Format rle produces a compact run length encoded bitonal file
39 that is understood by the DjVuLibre commands cjb2 and
40 csepdjvu.
41 When option -format is not specified, the extension of argument
43 outputfile has no influence on the default output format.
44 Instead the program behavior is modified to ensure backward com‐
45 patibility with previous versions of ddjvu. We recommend to
46 always specify the output format using this option.
47 -page=pagespec
49 Specify which pages should be decoded. When this option is not
50 specified, all pages of the documents are decoded and concate‐
51 nated into the output file. The page specification pagespec
52 contains one or more comma-separated page ranges. A page range
53 is either a page number, or two page numbers separated by a
54 dash. For instance, specification 1-10 outputs pages 1 to 10,
55 and specification 1,3,99999-4 outputs pages 1 and 3, followed by
56 all the document pages in reverse order up to page 4.
57 -mode=mod
59 Selects which layers of the DjVu image should be rendered.
60 Valid rendering modes are color, black, mask, foreground, and
61 background.
62 * Rendering mode color is the default mode. When the DjVu file
64 is bitonal, bitonal or gray-level output is produced depend‐
65 ing on the subsampling factor. Otherwise a color image is
66 produced.
67 * Rendering mode black is useful to extract a meaningful black
69 and white image. bitonal or gray-level output is produced
70 depending on the subsampling factor.
71 * Rendering modes mask, foreground, and background select spe‐
73 cific layers of a DjVu image. These modes can fail if the
74 DjVu image does not contain the selected layer.
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78 The following options control the resolution of the output image. The
79 default resolution is the native resolution of the DjVu file, equiva‐
80 lent to selecting -1.
81 -n Specify an integer sub-sampling factor. The dimensions of the
83 full output image will be n times smaller than the DjVu image
84 size. The legal values for argument n range from 1 to 12.
85 Option -1, for instance, produces an output image whose resolu‐
86 tion is equal to the resolution of the input DjVu image file.
87 -subsample=n
89 This is equivalent to option -n.
90 -scale=mag
92 Specify a magnification factor relative to the resolution stored
93 in the DjVu image. Specifying magnification of 100 produces an
94 image suitable for displaying on a 100 dpi device such as a com‐
95 puter screen. The magnification factor mag can also be inter‐
96 preted as the resolution of the output image expressed in dot
97 per inch.
98 -size=wxh
100 Specify the size of the full output image. Rendering the full
101 DjVu image would create an output image whose width and height
102 would not exceed w and h. To change the aspect ratio, you must
103 also use option -aspect=no.
104 -aspect=yesno
106 This option indicates whether the image aspect ratio should be
107 preserved. The defaults is to preserve the aspect ration. This
108 option permits changes in the aspect ratio when used in combina‐
109 tion with option -size.
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113 -verbose
114 Display informational messages describing the structure of the
115 DjVu image and the format of the output file.
116 -segment=wxh+x+y
118 Specify an image segment to render. Program ddjvu conceptually
119 renders the full page using the specified resolution, and then
120 extracts a sub-image of width w and height h, starting at posi‐
121 tion (x,y) relative to the bottom left corner of the page. Both
122 operations of course happen simultaneously. Rendering a small
123 sub-image is much faster than rendering the complete image. The
124 output file will always have size wxh when this option is speci‐
125 fied.
126 -quality=factor
128 Enables lossy compression in TIFF files. Without this option,
129 TIFF files always use lossless compression or no compression.
130 Argument factor specifies a JPEG quantization factor ranging
131 from 25 to 150. See command cjpeg(1) for more information on
132 JPEG quantization factors.
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136 Various options have been maintained to ensure backward compatibility
137 with previous versions of ddjvu. Please do not rely on these features.
138 When option -format is not specified, the program only decodes the
140 first page of the document and the default resolution becomes
141 -scale=100. Options -size, -scale, -segment, and -page accept an argu‐
142 ment separated by a space. Options -foreground, -background, and
143 -black are shorthands for the -mode=mod option.
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147 Command
148 ddjvu -format=tiff myfile.djvu myfile.tif
150 decodes all pages and produces a multipage TIFF file.
152 Command
154 ddjvu -format=ppm -page=1 -size=100x100 myfile.djvu -
156 produces a thumbnail for the first page of a document and outputs it as
158 a PPM file on the standard output:
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162 The new version of this program was written by Léon Bottou
163 <leonb@users.sourceforge.net>.
164
167 djvu(1), djview(1), pnm(5), pbm(5), pgm(5), ppm(5), cjpeg(1), tiffs‐
168 plit(1), tiffcp(1)
169DjVuLibre-3.5 10/19/2002 DDJVU(1)