Manual Reference Pages - FANT (1)
fant - perform simple spatial transforms on an image
-b blurfactor ]
xoff yoff ]
xscale yscale ]
xsize ysize ]
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.
-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
-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
-S xsize ysize |
An alternate method of specifying the scale factors.
ysize give the desired output image size.
The -S option can not be used in combination with -a, -p,
Verbose output. Primarily for debugging.
Fant, Karl M. "A Nonaliasing, Real-Time, Spatial Transform Technique",
IEEE CG&A, January, 1986, p. 71.
John W. Peterson,
James S. Painter
Fant uses a rather poor anti-aliasing filter (a triangle filter). This is usually
good enough but will exhibit noticeable aliasing artifacts on nasty
Visit the GSP FreeBSD Man Page Interface.
Output converted with manServer 1.07.