1 058b0118 2005-01-03 devnull .TH CROP 1
  2 058b0118 2005-01-03 devnull .SH NAME
  3 058b0118 2005-01-03 devnull crop, iconv \- frame, crop, and convert image
  4 058b0118 2005-01-03 devnull .SH SYNOPSIS
  5 058b0118 2005-01-03 devnull .B crop
  6 058b0118 2005-01-03 devnull [
  7 058b0118 2005-01-03 devnull .BI -c
  8 058b0118 2005-01-03 devnull .I red
  9 058b0118 2005-01-03 devnull .I green
 10 058b0118 2005-01-03 devnull .I blue
 11 058b0118 2005-01-03 devnull ]
 12 058b0118 2005-01-03 devnull [
 13 058b0118 2005-01-03 devnull .B -i
 14 058b0118 2005-01-03 devnull .I n
 15 058b0118 2005-01-03 devnull |
 16 058b0118 2005-01-03 devnull .B -x
 17 058b0118 2005-01-03 devnull .I dx
 18 058b0118 2005-01-03 devnull |
 19 058b0118 2005-01-03 devnull .B -y
 20 058b0118 2005-01-03 devnull .I dy
 21 058b0118 2005-01-03 devnull |
 22 058b0118 2005-01-03 devnull .B -r
 23 058b0118 2005-01-03 devnull .I minx
 24 058b0118 2005-01-03 devnull .I miny
 25 058b0118 2005-01-03 devnull .I maxx
 26 058b0118 2005-01-03 devnull .I maxy
 27 058b0118 2005-01-03 devnull ]
 28 058b0118 2005-01-03 devnull [
 29 058b0118 2005-01-03 devnull .B -t
 30 058b0118 2005-01-03 devnull .I tx
 31 058b0118 2005-01-03 devnull .I ty
 32 058b0118 2005-01-03 devnull ]
 33 058b0118 2005-01-03 devnull [
 34 058b0118 2005-01-03 devnull .B -b
 35 058b0118 2005-01-03 devnull .I red
 36 058b0118 2005-01-03 devnull .I green
 37 058b0118 2005-01-03 devnull .I blue
 38 058b0118 2005-01-03 devnull ]
 39 058b0118 2005-01-03 devnull [
 40 058b0118 2005-01-03 devnull .I file
 41 058b0118 2005-01-03 devnull ]
 42 058b0118 2005-01-03 devnull .PP
 43 058b0118 2005-01-03 devnull .B iconv
 44 058b0118 2005-01-03 devnull [
 45 058b0118 2005-01-03 devnull .B -u
 46 058b0118 2005-01-03 devnull ] [
 47 058b0118 2005-01-03 devnull .B -c
 48 058b0118 2005-01-03 devnull .I chandesc
 49 058b0118 2005-01-03 devnull ]
 50 058b0118 2005-01-03 devnull [
 51 058b0118 2005-01-03 devnull .I file
 52 058b0118 2005-01-03 devnull ]
 53 058b0118 2005-01-03 devnull .SH DESCRIPTION
 54 058b0118 2005-01-03 devnull .I Crop
 55 058b0118 2005-01-03 devnull reads an
 56 d32deab1 2020-08-16 rsc .MR image (7)
 57 058b0118 2005-01-03 devnull file (default standard input), crops it, and writes it as a compressed
 58 d32deab1 2020-08-16 rsc .MR image (7)
 59 058b0118 2005-01-03 devnull file to standard output.
 60 058b0118 2005-01-03 devnull There are two ways to specify a crop, by color value or by geometry.
 61 058b0118 2005-01-03 devnull They may be combined in a single run of
 62 058b0118 2005-01-03 devnull .IR crop ,
 63 058b0118 2005-01-03 devnull in which case the color value crop will be done first.
 64 058b0118 2005-01-03 devnull .PP
 65 058b0118 2005-01-03 devnull The
 66 058b0118 2005-01-03 devnull .B -c
 67 058b0118 2005-01-03 devnull option takes a red-green-blue triplet as described in
 68 d32deab1 2020-08-16 rsc .MR color (3) .
 69 058b0118 2005-01-03 devnull (For example, white
 70 058b0118 2005-01-03 devnull is
 71 058b0118 2005-01-03 devnull .B 255
 72 058b0118 2005-01-03 devnull .B 255
 73 058b0118 2005-01-03 devnull .BR 255 .)
 74 058b0118 2005-01-03 devnull The corresponding color is used as a value to be cut from the outer
 75 058b0118 2005-01-03 devnull edge of the picture; that is, the image is cropped to remove the maximal
 76 058b0118 2005-01-03 devnull outside rectangular strip in which every pixel has the specified color.
 77 058b0118 2005-01-03 devnull .PP
 78 058b0118 2005-01-03 devnull The
 79 058b0118 2005-01-03 devnull .B -i
 80 058b0118 2005-01-03 devnull option insets the image rectangle by a constant amount,
 81 058b0118 2005-01-03 devnull .IR n ,
 82 058b0118 2005-01-03 devnull which may be negative to generate extra space around the image.
 83 058b0118 2005-01-03 devnull The
 84 058b0118 2005-01-03 devnull .B -x
 85 058b0118 2005-01-03 devnull and
 86 058b0118 2005-01-03 devnull .B -y
 87 058b0118 2005-01-03 devnull options are similar, but apply only to the
 88 058b0118 2005-01-03 devnull .I x
 89 058b0118 2005-01-03 devnull or
 90 058b0118 2005-01-03 devnull .I y
 91 058b0118 2005-01-03 devnull coordinates of the image.
 92 058b0118 2005-01-03 devnull .PP
 93 058b0118 2005-01-03 devnull The
 94 058b0118 2005-01-03 devnull .B -r
 95 058b0118 2005-01-03 devnull option specifies an exact rectangle.
 96 058b0118 2005-01-03 devnull .PP
 97 058b0118 2005-01-03 devnull The 
 98 058b0118 2005-01-03 devnull .B -t
 99 058b0118 2005-01-03 devnull option specifies that the image's coordinate system should
100 058b0118 2005-01-03 devnull be translated by
101 058b0118 2005-01-03 devnull .IR tx ,
102 058b0118 2005-01-03 devnull .IR ty
103 058b0118 2005-01-03 devnull as the last step of processing.
104 058b0118 2005-01-03 devnull .PP
105 058b0118 2005-01-03 devnull The
106 058b0118 2005-01-03 devnull .B -b
107 058b0118 2005-01-03 devnull option specifies a background color to be used to fill around the image
108 058b0118 2005-01-03 devnull if the cropped image is larger than the original, such as if the
109 058b0118 2005-01-03 devnull .B -i
110 058b0118 2005-01-03 devnull option is given a negative argument.
111 058b0118 2005-01-03 devnull This can be used to draw a monochrome frame around the image.
112 058b0118 2005-01-03 devnull The default color is black.
113 058b0118 2005-01-03 devnull .PP
114 058b0118 2005-01-03 devnull .I Iconv
115 058b0118 2005-01-03 devnull changes the format of pixels in the image
116 058b0118 2005-01-03 devnull .I file
117 058b0118 2005-01-03 devnull (default standard input) and writes the resulting image to standard output.
118 058b0118 2005-01-03 devnull Pixels in the image are converted according to the channel descriptor
119 058b0118 2005-01-03 devnull .IR chandesc ,
120 058b0118 2005-01-03 devnull (see
121 d32deab1 2020-08-16 rsc .MR image (7) ).
122 058b0118 2005-01-03 devnull For example, to convert a 4-bit-per-pixel grey-scale image to an 8-bit-per-pixel
123 058b0118 2005-01-03 devnull color-mapped image,
124 058b0118 2005-01-03 devnull .I chandesc
125 058b0118 2005-01-03 devnull should be
126 058b0118 2005-01-03 devnull .BR m8 .
127 058b0118 2005-01-03 devnull If
128 058b0118 2005-01-03 devnull .I chandesc
129 058b0118 2005-01-03 devnull is not given, the format is unchanged.
130 058b0118 2005-01-03 devnull The output image is by default compressed; the
131 058b0118 2005-01-03 devnull .B -u
132 058b0118 2005-01-03 devnull option turns off the compression.
133 058b0118 2005-01-03 devnull .SH EXAMPLE
134 058b0118 2005-01-03 devnull To crop white edges off the picture and add a ten-pixel pink border,
135 058b0118 2005-01-03 devnull .IP
136 058b0118 2005-01-03 devnull .EX
137 058b0118 2005-01-03 devnull crop -c 255 255 255 -i -10 -b 255 150 150 imagefile > cropped
138 058b0118 2005-01-03 devnull .EE
139 058b0118 2005-01-03 devnull .SH SOURCE
140 c3674de4 2005-01-11 devnull .B \*9/src/cmd/draw/crop.c
141 058b0118 2005-01-03 devnull .SH SEE ALSO
142 d32deab1 2020-08-16 rsc .MR image (7) ,
143 d32deab1 2020-08-16 rsc .MR color (3)
144 058b0118 2005-01-03 devnull .SH BUGS
145 058b0118 2005-01-03 devnull .I Iconv
146 058b0118 2005-01-03 devnull should be able to do Floyd-Steinberg error diffusion or dithering
147 058b0118 2005-01-03 devnull when converting to small image depths.