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       tcrop.1 (2603B)
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            1 .TH CROP 1
            2 .SH NAME
            3 crop, iconv \- frame, crop, and convert image
            4 .SH SYNOPSIS
            5 .B crop
            6 [
            7 .BI -c
            8 .I red
            9 .I green
           10 .I blue
           11 ]
           12 [
           13 .B -i
           14 .I n
           15 |
           16 .B -x
           17 .I dx
           18 |
           19 .B -y
           20 .I dy
           21 |
           22 .B -r
           23 .I minx
           24 .I miny
           25 .I maxx
           26 .I maxy
           27 ]
           28 [
           29 .B -t
           30 .I tx
           31 .I ty
           32 ]
           33 [
           34 .B -b
           35 .I red
           36 .I green
           37 .I blue
           38 ]
           39 [
           40 .I file
           41 ]
           42 .PP
           43 .B iconv
           44 [
           45 .B -u
           46 ] [
           47 .B -c
           48 .I chandesc
           49 ]
           50 [
           51 .I file
           52 ]
           53 .SH DESCRIPTION
           54 .I Crop
           55 reads an
           56 .MR image (7)
           57 file (default standard input), crops it, and writes it as a compressed
           58 .MR image (7)
           59 file to standard output.
           60 There are two ways to specify a crop, by color value or by geometry.
           61 They may be combined in a single run of
           62 .IR crop ,
           63 in which case the color value crop will be done first.
           64 .PP
           65 The
           66 .B -c
           67 option takes a red-green-blue triplet as described in
           68 .MR color (3) .
           69 (For example, white
           70 is
           71 .B 255
           72 .B 255
           73 .BR 255 .)
           74 The corresponding color is used as a value to be cut from the outer
           75 edge of the picture; that is, the image is cropped to remove the maximal
           76 outside rectangular strip in which every pixel has the specified color.
           77 .PP
           78 The
           79 .B -i
           80 option insets the image rectangle by a constant amount,
           81 .IR n ,
           82 which may be negative to generate extra space around the image.
           83 The
           84 .B -x
           85 and
           86 .B -y
           87 options are similar, but apply only to the
           88 .I x
           89 or
           90 .I y
           91 coordinates of the image.
           92 .PP
           93 The
           94 .B -r
           95 option specifies an exact rectangle.
           96 .PP
           97 The 
           98 .B -t
           99 option specifies that the image's coordinate system should
          100 be translated by
          101 .IR tx ,
          102 .IR ty
          103 as the last step of processing.
          104 .PP
          105 The
          106 .B -b
          107 option specifies a background color to be used to fill around the image
          108 if the cropped image is larger than the original, such as if the
          109 .B -i
          110 option is given a negative argument.
          111 This can be used to draw a monochrome frame around the image.
          112 The default color is black.
          113 .PP
          114 .I Iconv
          115 changes the format of pixels in the image
          116 .I file
          117 (default standard input) and writes the resulting image to standard output.
          118 Pixels in the image are converted according to the channel descriptor
          119 .IR chandesc ,
          120 (see
          121 .MR image (7) ).
          122 For example, to convert a 4-bit-per-pixel grey-scale image to an 8-bit-per-pixel
          123 color-mapped image,
          124 .I chandesc
          125 should be
          126 .BR m8 .
          127 If
          128 .I chandesc
          129 is not given, the format is unchanged.
          130 The output image is by default compressed; the
          131 .B -u
          132 option turns off the compression.
          133 .SH EXAMPLE
          134 To crop white edges off the picture and add a ten-pixel pink border,
          135 .IP
          136 .EX
          137 crop -c 255 255 255 -i -10 -b 255 150 150 imagefile > cropped
          138 .EE
          139 .SH SOURCE
          140 .B \*9/src/cmd/draw/crop.c
          141 .SH SEE ALSO
          142 .MR image (7) ,
          143 .MR color (3)
          144 .SH BUGS
          145 .I Iconv
          146 should be able to do Floyd-Steinberg error diffusion or dithering
          147 when converting to small image depths.