3 crop, iconv \- frame, crop, and convert image
57 file (default standard input), crops it, and writes it as a compressed
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
63 in which case the color value crop will be done first.
67 option takes a red-green-blue triplet as described in
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.
80 option insets the image rectangle by a constant amount,
82 which may be negative to generate extra space around the image.
87 options are similar, but apply only to the
91 coordinates of the image.
95 option specifies an exact rectangle.
99 option specifies that the image's coordinate system should
103 as the last step of processing.
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
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.
115 changes the format of pixels in the image
117 (default standard input) and writes the resulting image to standard output.
118 Pixels in the image are converted according to the channel descriptor
122 For example, to convert a 4-bit-per-pixel grey-scale image to an 8-bit-per-pixel
129 is not given, the format is unchanged.
130 The output image is by default compressed; the
132 option turns off the compression.
134 To crop white edges off the picture and add a ten-pixel pink border,
137 crop -c 255 255 255 -i -10 -b 255 150 150 imagefile > cropped
140 .B \*9/src/cmd/draw/crop.c
146 should be able to do Floyd-Steinberg error diffusion or dithering
147 when converting to small image depths.