shift.im
Apply Vector Translation To Pixel Image
Applies a vector shift to a pixel image
Usage
# S3 method for im
shift(X, vec=c(0,0), …, origin=NULL)
Arguments
- X
Pixel image (object of class
"im"
).- vec
Vector of length 2 representing a translation.
- …
Ignored
- origin
Location that will be shifted to the origin. Either a numeric vector of length 2 giving the location, or a point pattern containing only one point, or a list with two entries named
x
andy
, or one of the character strings"centroid"
,"midpoint"
,"left"
,"right"
,"top"
,"bottom"
,"topleft"
,"bottomleft"
,"topright"
or"bottomright"
(partially matched).
Details
The spatial location of each pixel in the image
is translated by the vector vec
.
This is a method for the generic function shift
.
If origin
is given,
the argument vec
will be ignored; instead the shift will be performed
so that the specified geometric location is shifted to the
coordinate origin \((0,0)\).
The argument origin
should be either a numeric vector of length
2 giving the spatial coordinates of a location, or one of the character
strings "centroid"
, "midpoint"
,
"left"
, "right"
, "top"
, "bottom"
,
"topleft"
, "bottomleft"
, "topright"
or
"bottomright"
(partially matched).
If origin="centroid"
then the centroid of the window will be
shifted to the origin. If origin="midpoint"
then the centre of
the bounding rectangle of the window will be shifted to the origin.
If origin="bottomleft"
then the bottom left corner of the
bounding rectangle of the window will be shifted to the origin,
and so on.
Value
Another pixel image (of class "im"
) representing the
result of applying the vector shift.
See Also
Examples
# NOT RUN {
# make up an image
X <- setcov(unit.square())
plot(X)
Y <- shift(X, c(10,10))
plot(Y)
# no discernible difference except coordinates are different
shift(X, origin="c")
# }