CROP(1)                                                   CROP(1)

     NAME
          crop, iconv - frame, crop, and convert image

     SYNOPSIS
          crop [ -b red green blue ] [ -c red green blue ] [ -i n | -r
          minx miny maxx maxy | -x dx | -y dy ] [ -t tx ty ] [ -b red
          green blue ] [ file ]

          iconv [ -u ] [ -c chandesc ] [ file ]

     DESCRIPTION
          Crop reads an image(6) file (default standard input), crops
          it, and writes it as a compressed image(6) file to standard
          output.  There are two ways to specify a crop, by color
          value or by geometry.  They may be combined in a single run
          of crop, in which case the color value crop will be done
          first.

          The -c option takes a red-green-blue triplet as described in
          color(2). (For example, white is 255 255 255.)  The corre-
          sponding color is used as a value to be cut from the outer
          edge of the picture; that is, the image is cropped to remove
          the maximal outside rectangular strip in which every pixel
          has the specified color.

          The -i option insets the image rectangle by a constant
          amount, n, which may be negative to generate extra space
          around the image.  The -x and -y options are similar, but
          apply only to the x or y coordinates of the image.

          The -r option specifies an exact rectangle.

          The -t option specifies that the image's coordinate system
          should be translated by tx, ty as the last step of process-
          ing.

          The -b option specifies a background color to be used to
          fill around the image if the cropped image is larger than
          the original, such as if the -i option is given a negative
          argument.  This can be used to draw a monochrome frame
          around the image.  The default color is black.

          Iconv changes the format of pixels in the image file
          (default standard input) and writes the resulting image to
          standard output.  Pixels in the image are converted accord-
          ing to the channel descriptor chandesc, (see image(6)). For
          example, to convert a 4-bit-per-pixel grey-scale image to an
          8-bit-per-pixel color-mapped image, chandesc should be m8.
          If chandesc is not given, the format is unchanged.  The out-
          put image is by default compressed; the -u option turns off

     CROP(1)                                                   CROP(1)

          the compression.

     EXAMPLE
          To crop white edges off the picture and add a ten-pixel pink
          border,

               crop -c 255 255 255 -i -10 -b 255 150 150 imagefile > cropped

     SOURCE
          /sys/src/cmd/crop.c

     SEE ALSO
          image(6), color(2)

     BUGS
          Iconv should be able to do Floyd-Steinberg error diffusion
          or dithering when converting to small image depths.