1xcf2png(1) xcf2png(1)
2
6 xcf2png - convert from GIMP xcf files to png format
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9 xcf2png [ options ] filename [ layer names ]
10
12 xcf2png is a command-line tool that converts image files in the XCF
13 format used by gimp(1) to the generic image format png, flattening lay‐
14 ers if necessary. It does not need to have the Gimp engine itself
15 available.
16
18 -A, --force-alpha
19 Invent a trivial alpha channel even if the flattened image is
20 completely opaque.
21 -b color, --background color
23 Use this color for transparent pixels in the image. The color
24 can be given as #rrggbb or #rgb hexadecimal values, or as an
25 X11 color name (which will only work if a color name database
26 can be found in one of a number of standard locations).
27 -c, --color, --colour
29 Force the output to use RGB color space even if it there are
30 more compact alternatives.
31 -C, --autocrop
33 Set the converted part of the image such that it just include
34 the boundaries of the visible (or selected) layers. This may
35 make it either smaller or larger than the canvas, depending on
36 the position and size of the visible layers. (Note that the
37 contents of the layers is not taken into account when autocrop‐
38 ping).
39 In the absence of options that specify otherwise, the converted
41 image will cover the entire XCF canvas.
42 -D, --dissolve
44 Do a "dissolve" step to eliminate partial transparency after
45 flattening. If -b is also given, this happens before the back‐
46 ground color is applied.
47 -f, --full-image
49 First flatten the entire image to a memory buffer before writ‐
50 ing output. Then analyse the image to decide on the details of
51 the output format (e.g., whether a grayscale output is suffi‐
52 cient). Without this option, the program flattens only a singe
53 row of "tiles" (height 64) at a time.
54 -g, --gray, --grey
56 Force the output to be a grayscale image even if it may be
57 monochrome. If any colored pixels are encountered, exit with
58 status 103. This will be selected automatically if the output
59 file's name ends with .pgm.
60 -G, --for-gif
62 Assert that the flattened image will have no partial trans‐
63 parency (allowing a more compact representation of the alpha
64 output). Exit with status 102 if the flattened image has any
65 partial transparency. If -b is also given, this tests whether
66 there there is partial transparency before applying the back‐
67 ground color.
68 -h, --help
70 Print an option summery to standard output and exit with a
71 return code of 0.
72 -j, --bzip
74 Equivalent to -Z bzcat. Default if the filename ends with bz2.
75 -o filename, --output filename
77 Write the converted picture to filename instead of to standard
78 output.
79 -O x,y, --offset x,y
81 Offset the converted part of the image from the top-left corner
82 of the XCF canvas. Usually used with -S.
83 -S wxh, --size wxh
85 Crop the converted image to width w and height h.
86 -T, --truecolor
88 Use standard RGB compositing for flattening indexed layers.
89 Without this option, xcf2png will mimic the Gimp's current
90 strategy of rounding each alpha value to either full trans‐
91 parency or full opacity, and interpret all layer modes as Nor‐
92 mal.
93 -u, --utf8
95 Use the raw UTF-8 representation from the XCF file to compare
96 and display layer names. Ordinarily, layer names will be con‐
97 verted to the character set of the current locale.
98 -v, --verbose
100 Print progress messages about the conversion to standard error.
101 -V, --version
103 Print the version numer of xcftools to standard output and exit
104 with a return code of 0.
105 -z, --gzip
107 Equivalent to -Z zcat. Default if the filename ends with gz.
108 -Z command, --unpack command
110 Specify a command that the input file is filtered through
111 before being interpreted as an XCF file. The command is invoked
112 as command filename and must produce output to its standard
113 output. Note that it is not possible to specify arguments as
114 part of command. An uncompressor is selected automatically if
115 the filename ends with gz or bz2; to suppress this, use -Z cat
116 (which is implemented without actually starting a cat(1)
117 process).
118 Several groups of options are mutually incompatible; in each group the
120 one given last will win:
121 1) -A and -b.
123 2) -g and -c .
125 3) -D and -G.
127 4) -j, -z, and -Z.
129 5) -C and -O/-S.
131
133 If no layer name is given on the command line, all of the visible lay‐
134 ers in the XCF file are merged to produce the output image. It is also
135 possible to specify the layers to merge explicitly, by giving their
136 names as separate arguments after the input filename. In that case, the
137 output will contain only the named layers. The layers will be merged in
138 the order they appear on the command line, with the leftmost being "at
139 the bottom" - that is, the layer ordering in the XCF file will be
140 ignored.
141 The following options can be given after a layer name to override the
143 global properties of the layer:
144 --mask Enable the layer mask.
146 --mode mode
148 Set the layer mode (e.g., Normal or Multiply).
149 --nomask
151 Disable the layer mask.
152 --opacity n
154 Set the opacity on a scale from 0 to 255 (as used internally)
155 --percent n
157 Set the opacity on a scale from 0 to 100 (as in the Gimp user
158 interface).
159
161 The exit status of xcf2png is
162 0 Success
164 20 Problems parsing the command line, including unknown color names
166 (or missing color name directory) for -b.
167 21 The specified XCF file does not exist or cannot be read.
169 22 A layer named on the command line was not found, or the --mask
171 option was used for a layer that has no layer mask.
172 102 The -G option was given, yet partial transparency was found.
174 103 -g was given, yet colored pixels were found.
176 123 The XCF file contains presumably valid features that xcftools does
178 not support. (As of this writing there is no known way of getting
179 the Gimp to write an XCF file that will provoke this return.
180 Please notify the author if you discover one).
181 125 The XCF file is malformed.
183 126 An uncompression program could not be executed, or terminated
185 abnormally.
186 127 Unexpected I/O error, internal errors, or other "this can't hap‐
188 pen" situations.
189 If an uncompression program returns an error exit status, this will be
191 returned from xcf2png too.
192
194 When several partially transparent layers are merged, the pixel values
195 are interpolated without gamma correction. (The Gimp also does it this
196 way). Some slight rounding errors in the interpolation are inevitable;
197 xcf2png sometimes has different rounding errors than the Gimp itself,
198 especially when more than two layers are involved, or in case of some
199 of the more exotic layer modes. These differences are usually not vis‐
200 ible to the eye.
201 Floating selections are currently not handled correctly.
203 There are probably other bugs lurking in corner cases. If you discover
205 one, please notify the author.
206
209 /etc/X11/rgb.txt
210 /usr/share/X11/rgb.txt
212 /usr/lib/X11/rgb.txt
214 Color name database for -b.
215
217 xcf2png was written by Henning Makholm <henning@makholm.net>.
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220 xcfinfo(1), xcf2pnm(1)
221Xcftools 2006-02-12 xcf2png(1)