FANT(1)FANT(1)NAMEfant - perform simple spatial transforms on an image
SYNOPSISfant [ -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 trans‐
formation. 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 ALSOavg4(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)
