#
# pspcross.R
#
# Intersections of line segments
#
# $Revision: 1.3 $ $Date: 2007/03/16 13:32:41 $
#
#
crossing.psp <- function(A,B) {
verifyclass(A, "psp")
verifyclass(B, "psp")
eps <- .Machine$double.eps
na <- A$n
eA <- A$ends
x0a <- eA$x0
y0a <- eA$y0
dxa <- eA$x1 - eA$x0
dya <- eA$y1 - eA$y0
nb <- B$n
eB <- B$ends
x0b <- eB$x0
y0b <- eB$y0
dxb <- eB$x1 - eB$x0
dyb <- eB$y1 - eB$y0
out <- .C("xysegint",
na=as.integer(na),
x0a=as.double(x0a),
y0a=as.double(y0a),
dxa=as.double(dxa),
dya=as.double(dya),
nb=as.integer(nb),
x0b=as.double(x0b),
y0b=as.double(y0b),
dxb=as.double(dxb),
dyb=as.double(dyb),
eps=as.double(eps),
xx=as.double(numeric(na * nb)),
yy=as.double(numeric(na * nb)),
ta=as.double(numeric(na * nb)),
tb=as.double(numeric(na * nb)),
ok=as.integer(integer(na * nb)),
PACKAGE="spatstat")
ok <- (matrix(out$ok, na, nb) != 0)
xx <- matrix(out$xx, na, nb)
yy <- matrix(out$yy, na, nb)
xx <- as.vector(xx[ok])
yy <- as.vector(yy[ok])
result <- ppp(xx, yy, window=intersect.owin(A$window, B$window), check=FALSE)
return(result)
}
test.crossing.psp <- function(A,B) {
verifyclass(A, "psp")
verifyclass(B, "psp")
eps <- .Machine$double.eps
na <- A$n
eA <- A$ends
x0a <- eA$x0
y0a <- eA$y0
dxa <- eA$x1 - eA$x0
dya <- eA$y1 - eA$y0
nb <- B$n
eB <- B$ends
x0b <- eB$x0
y0b <- eB$y0
dxb <- eB$x1 - eB$x0
dyb <- eB$y1 - eB$y0
out <- .C("xysi",
na=as.integer(na),
x0a=as.double(x0a),
y0a=as.double(y0a),
dxa=as.double(dxa),
dya=as.double(dya),
nb=as.integer(nb),
x0b=as.double(x0b),
y0b=as.double(y0b),
dxb=as.double(dxb),
dyb=as.double(dyb),
eps=as.double(eps),
ok=as.integer(integer(1)),
PACKAGE="spatstat")$ok
return(out != 0)
}
selfcrossing.psp <- function(A) {
verifyclass(A, "psp")
eps <- .Machine$double.eps
n <- A$n
eA <- A$ends
x0 <- eA$x0
y0 <- eA$y0
dx <- eA$x1 - eA$x0
dy <- eA$y1 - eA$y0
out <- .C("xysegXint",
n=as.integer(n),
x0=as.double(x0),
y0=as.double(y0),
dx=as.double(dx),
dy=as.double(dy),
eps=as.double(eps),
xx=as.double(numeric(n^2)),
yy=as.double(numeric(n^2)),
ti=as.double(numeric(n^2)),
tj=as.double(numeric(n^2)),
ok=as.integer(integer(n^2)),
PACKAGE="spatstat")
ok <- (matrix(out$ok, n, n) != 0)
xx <- matrix(out$xx, n, n)
yy <- matrix(out$yy, n, n)
xx <- as.vector(xx[ok])
yy <- as.vector(yy[ok])
result <- ppp(xx, yy, window=A$window, check=FALSE)
return(result)
}