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FANT(1)			    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 in-
       terpolation if the image	size is	increased.  Because it works with sub-
       pixel 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 de-
	      crease 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  ro-
	      tated  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  of-
	      ten  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	  Dec 4, 1990			       FANT(1)

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | SEE ALSO | AUTHORS | BUGS

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