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FANT(1)                DragonFly General Commands Manual               FANT(1)

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.

       -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.

4th Berkeley Distribution      December 4, 1990                        FANT(1)