NAME
      fant - perform simple spatial transforms on
      an image

 SYNOPSIS
      fant [ -a angle ] [ -b blurfactor ] [ -o outfile ] [ -p xoff yoff ] [
      -s xscale yscale ] [ -S xsize ysize ] [ -v ] [ infile ]

 DESCRIPTION
      Fant rotates or scales an image by an
      arbitrary amount.  It does this by using
      pixel integration (if the image size is
      reduced) or pixel interpolation if the image
      size is increased.  Because it works with
      subpixel precision, aliasing artifacts are
      not introduced (hah! see BUGS). Fant uses a
      two-pass sampling technique to perform the
      transformation.  If infile is "-" or absent,
      input is read from the standard input.

 OPTIONS
      -a angle
           Amount to rotate image by, a real number
           from 0 to 45 degrees (positive numbers
           rotate clockwise).  Use rleflip(1) first
           to rotate an image by larger amounts.

      -b blur_factor
           Control the amount of blurring in the
           output image. If the blur factor is
           greater than one, image blurring will
           increase.  If the blur factor is smaller
           than one, image blurring will decrease
           but aliasing artifacts may be visible.


      -o outfile
           Specifies where to place the resulting
           image.  The default is to write to
           stdout.  If outfile is "-", the output
           will be written to the standard output
           stream.

      -p xoff yoff
           Specifies where the origin of the image
           is - the image is rotated or scaled
           about this point.  If no origin is
           specified, the center of the image is
           used.

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      -s xscale yscale
           The amount (in real numbers) to scale an
           image by.  This is often useful for
           correcting the aspect of an image for
           display on a frame buffer with non
           square pixels.  For this use, the origin
           should be specified as 0, 0 (see -p
           above).  If an image is only scaled in Y
           and no rotation is performed, fant only
           uses one sampling pass over the image,
           cutting the computation time in half.

      -S xsize ysize
           An alternate method of specifying the
           scale factors. xsize and ysize give the
           desired output image size.

           The -S option can not be used in
           combination with -a, -p, or -s.


      -v   Verbose output.  Primarily for
           debugging.

 SEE ALSO
      avg4(1), rleflip(1), rlezoom(1), urt(1),
      RLE(5),
      Fant, Karl M. "A Nonaliasing, Real-Time,
      Spatial Transform Technique", IEEE CG&A,
      January, 1986, p. 71.

 AUTHORS
      John W. Peterson, James S. Painter

 BUGS
      Fant uses a rather poor anti-aliasing filter
      (a triangle filter).  This is usually good
      enough but will exhibit noticeable aliasing
      artifacts on nasty input images.











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