Return Value: 1 on success, 0 on failure.
DESCRIPTION
vflip performs reflection or "flip" operations on an image.
The flip can be specified to be top-for-bottom or right-
for-left or both (which does a 180 degree rotation.
Note that image is used for both the input xvimage structure
and the resulting output xvimage structure. This is done to
save space, but you must be careful not to overwrite impor-
tant data.
SEE ALSO
vflip(1), intro(3), vipl(3), verror(3), vutils(3) vro-
tate(1), vwarp(1)
RESTRICTIONS
vflip does not work on BIT, COMPLEX, or transformed data
types. vflip will work with explicit location data, but
only the image part will be flipped. The location data will
not be flipped.
AUTHOR
Scott Wilson
COPYRIGHT
Copyright 1991, University of New Mexico. All rights
reserved.
*********************************************************************************
Documentation for avs module vresize
INPUT
image pointer to xvimage structure to be processed
hmag magnification factor in the horizontal (X)
direction (float)
vmag magnification factor in the vertical (Y)
direction (float)
xc X coordinate of center of action (float)
yc Y coordinate of center of action (float)
OUTPUT
image holds the result of the resize operation.
The output data type is the same as the input
data type.
Return Value: 1 on success, 0 on failure.
DESCRIPTION
vresize is used to magnify or reduce an image by using bil-
inear 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 factor cannot be zero.
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 magni-
fying glass over the point of interest and then choose the
lens to get the magnification you want.
Note that image is used for both the input xvimage structure
and the resulting output xvimage structure. This is done to
save space, but you must be careful not to overwrite impor-
tant data.
SEE ALSO
vresize(1), intro(3), vipl(3), verror(3), vutils(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.
AUTHOR
Scott Wilson
COPYRIGHT
Copyright 1991, University of New Mexico. All rights
reserved.
*********************************************************************************
Documentation for avs module vrotate
INPUT
image pointer to xvimage structure to be processed
ang angle in degrees to rotate by, positive is
clockwise (float)
xc X coordinate of center of rotation (float)
yc Y coordinate of center of rotation (float)
OUTPUT
image holds the result of the operation. The out-
put data type is the same as the input data
type.
Return Value: 1 on success, 0 on failure.
DESCRIPTION
vrotate rotates an image by a specfied angle, about a
specified point. The rotation is performed using bilinear
interpolation. Portions of the output image that do not have
a corresponding pixel in the input image are set to zero.
Note that image is used for both the input xvimage structure
and the resulting output xvimage structure. This is done to
save space, but you must be careful not to overwrite impor-
tant data.
SEE ALSO
vrotate(1), intro(3), vipl(3), verror(3), vutils(3)
vresize(1), vwarp(1), vshrink(1), vexpand(1)
RESTRICTIONS
vrotate does not work on BIT or COMPLEX data types. vro-
tate does not work on explicit location data.
AUTHOR
Scott Wilson
COPYRIGHT
Copyright 1991, University of New Mexico. All rights
reserved.
*********************************************************************************
Documentation for avs module vshrink
INPUT
image pointer to xvimage structure to be processed
scale size reduction factor (integer), must be pos-
titive, non-zero
OUTPUT
image holds the result of the operation. The out-
put data type is the same as the input data
type.
Return Value: 1 on success, 0 on failure.
DESCRIPTION
vshrink decreases the size of an image by skipping to
every s'th pixel where s is the scale argument. The resul-
tant image will be 1/s the size of the original image.
The scale factor must be a positive, non-zero number.
The output data type is the same asn the input data type.
Note that image is used for both the input xvimage structure
and the resulting output xvimage structure. This is done to
save space, but you must be careful not to overwrite impor-
tant data.
SEE ALSO
vshrink(1), intro(3), vipl(3), verror(3), vutils(3) vex-
pand(1), vresize(1)
RESTRICTIONS
vshrink does not work on COMPLEX data types. vshrink does
not work on explicit location data.
AUTHOR
Scott Wilson
COPYRIGHT
Copyright 1991, University of New Mexico. All rights
reserved.
*********************************************************************************
Documentation fora avs module vtranslat
INPUT
img - an xvimage structure (input image).
vi - integer: Translation along i axis
vj - integer: Translation along j axis
wflg - integer: flag set to one if wrapping selected or
zero if padding with padding value
pad - float: padding value used to set the pixels of
the result image that have not received any value dur-
ing the translation process.
OUTPUT
img - Holds the result of the translation.
DESCRIPTION
vtranslat Computes the translation of an xvimage structure
by a vector (i,j).
Includes a Wrap option or a padding value.
The tranlation is processed in the following manner:
For each pixel (x,y) of the input image, the algorithm cal-
culates the transformed coordinates (x+i,y+j) and determines
if the translated pixel is outside of the output image.
If the new pixel is inside of the image border, its
initial value is stored in its new location.
If the new location does not fit inside of the image, a
modulo (size of rows and columns) is taken into con-
sideration to write either the padding value in the
output image (if wrap flag not selected) or the initial
value of the pixel (x,y) (if wrap selected).
SEE ALSO
vtranslat(1), intro(3), vipl(3), verror(3), vutils(3)
vtranslat(1)
RESTRICTIONS
vtranslat will not operate on Bit data storage types.
vtranslat does not work on explicit location data.
AUTHOR
Pascal ADAM
COPYRIGHT
Copyright 1991, University of New Mexico. All rights
reserved.
*********************************************************************************
Documentation for avs module vtranspos
INPUT
img - a pointer on an xvimage structure.
OUTPUT
img - holds the result of the transposition.
DESCRIPTION
ltranspos Computes the transpose of the rows and columns in
an image.
The transpose is computed by scanning the input image and
applying the function:
Transpose(x,y) = pixel(y,x)
SEE ALSO
vtranspos(1), intro(3), vipl(3), verror(3), vutils(3) vtran-
spos(1)
RESTRICTIONS
vtranspos will not operate on Bit, DOUBLE, or DCOMPLEX data
storage types. vtranspos will not operate on explicit
location data.
AUTHOR
Pascal ADAM
COPYRIGHT
Copyright 1991, University of New Mexico. All rights
reserved.
*********************************************************************************