scalardilate
Apply Scalar Dilation
Applies scalar dilation to a plane geometrical object, such as a point pattern or a window, relative to a specified origin.
Usage
scalardilate(X, f, …) # S3 method for im
scalardilate(X, f, …, origin=NULL)
# S3 method for owin
scalardilate(X, f, …, origin=NULL)
# S3 method for ppp
scalardilate(X, f, …, origin=NULL)
# S3 method for psp
scalardilate(X, f, …, origin=NULL)
# S3 method for default
scalardilate(X, f, …)
Arguments
- X
Any suitable dataset representing a two-dimensional object, such as a point pattern (object of class
"ppp"
), a window (object of class"owin"
), a pixel image (class"im"
) and so on.- f
Scalar dilation factor. A finite number greater than zero.
- …
Ignored by the methods.
- origin
Origin for the scalar dilation. Either a vector of 2 numbers, or one of the character strings
"centroid"
,"midpoint"
,"left"
,"right"
,"top"
,"bottom"
,"topleft"
,"bottomleft"
,"topright"
or"bottomright"
(partially matched).
Details
This command performs scalar dilation of the object X
by the factor f
relative to the origin specified by
origin
.
The function scalardilate
is generic, with methods for
windows (class "owin"
), point patterns (class "ppp"
),
pixel images (class "im"
), line segment patterns (class "psp"
)
and a default method.
If the argument origin
is not given,
then every spatial coordinate is multiplied by the factor f
.
If origin
is given, then scalar dilation is performed
relative to the specified origin. Effectively, X
is shifted
so that origin
is moved to c(0,0)
, then scalar dilation
is performed, then the result is shifted so that c(0,0)
is
moved to origin
.
This command is a special case of an affine transformation:
see affine
.
Value
Another object of the same type, representing the result of applying the scalar dilation.
See Also
Examples
# NOT RUN {
plot(letterR)
plot(scalardilate(letterR, 0.7, origin="left"), col="red", add=TRUE)
# }