vresize(1)

PROGRAM
vresize - Magnify or reduce an image using bilinear interpolation

SYNTAX

vresize

-i  input image

-o  resulting output image

[-x]
    x coordinate of the center of action

[-y]
    y coordinate of the center of action

[-h]
    magnification in the horizontal direction

[-v]
    magnification in the vertical direction

[-V]
    Gives the version for vresize

[-U]
    Gives the usage for vresize

[-P]
    Prompts for command line options

[-A [file1]]
    Creates the answer file called vresize.ans or file1

[-a [file1]]
    Uses vresize.ans or file1 as the answer file

DESCRIPTION
vresize is used to magnify or reduce an image by using bilinear interpolation. The resultant image is the same size and type as the original, but the pixels in the input image are magnified or reduced in the output image.

If the input image is reduced (magnification factor < 1.0) then unknown pixels are set to zero.

If the input image is magnified (magnification factor > 1.0) then input pixels that would be mapped outside of the output image are lost.

The magnification or reduction is done about a center point that can be specified to be anywhere in the X-Y plane (even outside the image). The correct way to think about this is by analogy to a magnifying glass where you place the magnifying glass over the point of interest and then choose the lens to get the magnification you want.

REQUIRED ARGUMENTS

-i  type: infile
    desc: input image

-o  type: outfile
    desc: resulting output image

OPTIONAL ARGUMENTS

-x  type: float
    desc: x coordinate of the center of action
    default: 0
    bounds: value >= 0.0

-y  type: float
    desc: y coordinate of the center of action
    default: 0
    bounds: value >= 0.0

-h  type: float
    desc: magnification in the horizontal direction
    default: 2
    bounds: value > 0.0

-v  type: float
    desc: magnification in the vertical direction
    default: 2
    bounds: value > 0.0

EXAMPLES
vresize -i feath.xv -o feath.nose.xv -x 315 -y 315 -h 10 -v 10

produces an image of the pretty girl's nose, magnified by a factor of 10.

SEE ALSO
intro(1), verror(3), vgparms(3), vutils(3), lvresize(3) vwarp(1), vshrink(1), vexpand(1), vrotate(1)

RESTRICTIONS
vresize does not work on COMPLEX data types. vresize does not work on explicit location data.

COPYRIGHT
Copyright 1991, University of New Mexico. All rights reserved.