resample – resample a picture

resample [ –x size ] [ –y size ] [ file ]

Resample resamples its input image (default standard input) to a new size. The image is decimated or interpolated using a Kaiser window.

The size of the resampled image can be specified with the –x and –y options. An unadorned value sets the number of pixels of that dimension; a suffixed percent sign specifies a percentage. If only one of –x or –y is given, the other dimension is scaled to preserve the aspect ratio of the original image. Thus, –x50% will reduce the image to half its original dimension in both x and y.

The input should be a Plan 9 image as described in image(6), and the output will be a compressed 24–bit r8g8b8 image. To uncompress the image or change the pixel format, use iconv (see crop(1)).


crop(1), image(6)

Faster algorithms exist, but this implementation produces correct pictures.
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