Nothing
R/cgalPolygon.R
In cgalPolygons: R6 Based Utilities for Polygons using 'CGAL'
Defines functions
getXPtr
getXPtr <- function(cPolygon){
cPolygon[[".__enclos_env__"]][["private"]][[".CGALpolygon"]][["xptr"]]
}
#' @title R6 class to represent a CGAL polygon
#' @description R6 class to represent a CGAL polygon.
#'
#' @importFrom R6 R6Class
#' @export
cgalPolygon <- R6Class(
"cgalPolygon",
lock_class = TRUE,
cloneable = FALSE,
private = list(
".CGALpolygon" = NULL,
".vertices" = NULL
),
public = list(
#' @description Creates a new \code{cgalpolygon} object.
#' @param vertices a numeric matrix with two columns
#' @return A \code{cgalPolygon} object.
#' @examples
#' library(cgalPolygons)
#' ptg <- cgalPolygon$new(pentagram)
#' ptg
"initialize" = function(vertices) {
# one can also initialize from an external pointer, but
# this is hidden to the user
if(inherits(vertices, "externalptr")) {
private[[".CGALpolygon"]] <- CGALpolygon$new(vertices, TRUE)
return(invisible(self))
}
stopifnot(is.matrix(vertices))
stopifnot(ncol(vertices) == 2L)
stopifnot(nrow(vertices) >= 3L)
storage.mode(vertices) <- "double"
stopifnot(noMissingValue(vertices))
private[[".CGALpolygon"]] <- CGALpolygon$new(t(vertices))
private[[".vertices"]] <- vertices
invisible(self)
},
#' @description Print the \code{cgalPolygon} object.
#' @param ... ignored
#' @return No value, just prints some information about the polygon.
"print" = function(...) {
private[[".CGALpolygon"]]$print()
},
#' @description Signed area of the polygon.
#' @return A number, the signed area of the polygon; it is positive if the
#' polygon is counter-clockwise oriented, negative otherwise.
#' @examples
#' library(cgalPolygons)
#' ptg <- cgalPolygon$new(pentagram)
#' ptg$area() # should be 5 / sqrt(130 + 58*sqrt(5))
#' 5 / sqrt(130 + 58*sqrt(5))
"area" = function() {
private[[".CGALpolygon"]]$area()
},
#' @description Bounding box of the polygon.
#' @return A 2x2 matrix giving the lower corner of the bounding box in its
#' first row and the upper corner in its second row.
#' @examples
#' library(cgalPolygons)
#' ptg <- cgalPolygon$new(pentagram)
#' plot(ptg$boundingBox(), asp = 1)
#' polygon(pentagram)
"boundingBox" = function() {
private[[".CGALpolygon"]]$boundingBox()
},
#' @description Decomposition into convex parts. The polygon must be simple
#' and counter-clockwise oriented.
#' @param method the method used: \code{"approx"}, \code{"greene"},
#' or \code{"optimal"}
#' @return A list of matrices; each matrix has two columns and represents
#' a convex polygon.
#' @examples
#' library(cgalPolygons)
#' ptg <- cgalPolygon$new(pentagram)
#' cxparts <- ptg$convexParts()
#' ptg$plot(col = "yellow", lwd = 3)
#' invisible(
#' lapply(cxparts, function(cxpart) {
#' polygon(cxpart, lwd = 2)
#' })
#' )
"convexParts" = function(method = "optimal") {
method <- match.arg(method, c("approx", "greene", "optimal"))
if(method == "approx") {
private[[".CGALpolygon"]]$approxConvexParts()
} else if(method == "greene") {
private[[".CGALpolygon"]]$greeneApproxConvexParts()
} else {
private[[".CGALpolygon"]]$optimalConvexParts()
}
},
#' @description Vertices of the polygon.
#' @return The vertices in a matrix with two columns.
#' @examples
#' library(cgalPolygons)
#' ptg <- cgalPolygon$new(pentagram)
#' ptg$getVertices()
"getVertices" = function() {
private[[".vertices"]]
},
#' @description Intersection of the polygon with another polygon.
#' @param plg2 a \code{cgalPolygon} object or a \code{cgalPolygonWithHoles}
#' object
#' @return A list whose each element is either a \code{cgalPolygon} object
#' or a \code{cgalPolygonWithHoles} object.
#' @examples
#' library(cgalPolygons)
#' # function creating a circle
#' circle <- function(x, y, r) {
#' t <- seq(0, 2, length.out = 100)[-1L]
#' t(c(x, y) + r * rbind(cospi(t), sinpi(t)))
#' }
#' # take two circles
#' plg1 <- cgalPolygon$new(circle(-1, 0, 1.25))
#' plg2 <- cgalPolygon$new(circle(1, 0, 1.25))
#' # intersection
#' plgList <- plg1$intersection(plg2)
#' plg <- plgList[[1L]]
#' # plot
#' opar <- par(mar = c(0, 0, 0, 0))
#' plot(
#' NULL, xlim = c(-2.6, 2.6), ylim = c(-1.3, 1.3), asp = 1,
#' xlab = NA, ylab = NA, axes = FALSE
#' )
#' plg1$plot(lwd = 2, new = FALSE)
#' plg2$plot(lwd = 2, new = FALSE)
#' plg$plot(lwd = 3, col = "red", new = FALSE)
#' par(opar)
"intersection" = function(plg2) {
stopifnot(isCGALpolygon(plg2) || isCGALpolygonWithHoles(plg2))
if(isCGALpolygonWithHoles(plg2)) {
return(plg2$intersection(self))
}
xptr2 <- getXPtr(plg2)
plgs <- private[[".CGALpolygon"]]$boolop_intersection(xptr2)
# output
out <- vector("list", length = length(plgs))
for(i in seq_along(plgs)) {
plg <- plgs[[i]]
holes <- plg[["holes"]]
if(length(holes) == 0L) {
out[[i]] <- cgalPolygon$new(vertices = plg[["outer"]])
} else {
out[[i]] <- cgalPolygonWithHoles$new(
outerVertices = plg[["outer"]], holes = holes
)
}
}
out
},
#' @description Checks whether the polygon is clockwise oriented.
#' @return A Boolean value.
#' @examples
#' library(cgalPolygons)
#' ptg <- cgalPolygon$new(pentagram)
#' ptg$isCWO()
"isCWO" = function() {
private[[".CGALpolygon"]]$isCWO()
},
#' @description Checks whether the polygon is counter-clockwise oriented.
#' @return A Boolean value.
#' @examples
#' library(cgalPolygons)
#' ptg <- cgalPolygon$new(pentagram)
#' ptg$isCCWO()
"isCCWO" = function() {
private[[".CGALpolygon"]]$isCCWO()
},
#' @description Checks whether the polygon is convex.
#' @return A Boolean value.
#' @examples
#' library(cgalPolygons)
#' ptg <- cgalPolygon$new(pentagram)
#' ptg$isConvex()
"isConvex" = function() {
private[[".CGALpolygon"]]$isConvex()
},
#' @description Checks whether the polygon is simple; that means its edges
#' do not intersect (except two consecutive edges which intersect at
#' their common vertex)
#' @return A Boolean value.
#' @examples
#' library(cgalPolygons)
#' ptg <- cgalPolygon$new(pentagram)
#' ptg$isSimple()
"isSimple" = function() {
private[[".CGALpolygon"]]$isSimple()
},
#' @description Minkowski sum of the polygon and another polygon.
#' @param plg2 a \code{cgalPolygon} object or a \code{cgalPolygonWithHoles}
#' object, the polygon to add to the reference polygon
#' @return Either a \code{cgalPolygonWithHoles} object, or, in the case if
#' there is no hole in the Minkowski sum, a \code{cgalPolygon} object.
#' @examples
#' library(cgalPolygons)
#' plg1 <- cgalPolygon$new(decagram)
#' plg2 <- cgalPolygon$new(star)
#' minko <- plg1$minkowskiSum(plg2)
#' minko$plot(lwd = 2, col = "yellowgreen")
"minkowskiSum" = function(plg2) {
stopifnot(isCGALpolygon(plg2) || isCGALpolygonWithHoles(plg2))
if(isCGALpolygonWithHoles(plg2)) {
return(plg2$minkowskiSum(self, method = "convolution"))
}
xptr <- getXPtr(plg2)
msum <- private[[".CGALpolygon"]]$minkowskiC(xptr)
holes <- msum[["holes"]]
nholes <- length(holes)
if(nholes == 0L) {
message("No hole in the Minkowski sum.")
cgalPolygon$new(vertices = msum[["outer"]])
} else {
if(nholes == 1L){
msg <- "There is one hole in the Minkowski sum."
} else {
msg <- sprintf(
"There are %d holes in the Minkowski sum.", nholes
)
}
message(msg)
cgalPolygonWithHoles$new(
outerVertices = msum[["outer"]], holes = holes
)
}
},
#' @description Plot the polygon.
#' @param ... arguments passed to \code{\link[graphics]{polygon}}
#' @param new Boolean, whether to create a new plot
#' @return No returned value, called for side-effect.
#' @importFrom graphics plot polygon
#' @examples
#' library(cgalPolygons)
#' ptg <- cgalPolygon$new(pentagram)
#' ptg$plot(lwd = 3, col = "red")
"plot" = function(..., new = TRUE) {
stopifnot(isBoolean(new))
if(new) {
bbox <- private[[".CGALpolygon"]]$boundingBox()
plot(bbox, type = "n", asp = 1, xlab = NA, ylab = NA, axes = FALSE)
}
polygon(private[[".vertices"]], ...)
invisible(NULL)
},
#' @description Reverse the orientation of the polygon.
#' @return The \code{cgalPolygon} object, invisibly.
#' @examples
#' library(cgalPolygons)
#' ptg <- cgalPolygon$new(pentagram)
#' ptg$isCCWO()
#' ptg$reverseOrientation()
#' ptg$isCCWO()
"reverseOrientation" = function() {
vertices <- private[[".CGALpolygon"]]$reverseOrientation()
private[[".vertices"]] <- vertices
invisible(self)
},
#' @description Difference between the polygon and another polygon.
#' @param plg2 a \code{cgalPolygon} object or a \code{cgalPolygonWithHoles}
#' object
#' @return A list whose each element is either a \code{cgalPolygon} object
#' or a \code{cgalPolygonWithHoles} object.
#' @examples
#' library(cgalPolygons)
#' # function creating a circle
#' circle <- function(x, y, r) {
#' t <- seq(0, 2, length.out = 100)[-1L]
#' t(c(x, y) + r * rbind(cospi(t), sinpi(t)))
#' }
#' # take two circles
#' plg1 <- cgalPolygon$new(circle(-1, 0, 1.25))
#' plg2 <- cgalPolygon$new(circle(1, 0, 1.25))
#' # difference
#' plgList <- plg1$subtract(plg2)
#' plg <- plgList[[1L]]
#' # plot
#' opar <- par(mar = c(0, 0, 0, 0))
#' plot(
#' NULL, xlim = c(-2.6, 2.6), ylim = c(-1.3, 1.3), asp = 1,
#' xlab = NA, ylab = NA, axes = FALSE
#' )
#' plg1$plot(lwd = 2, new = FALSE)
#' plg2$plot(lwd = 2, new = FALSE)
#' plg$plot(lwd = 3, col = "red", new = FALSE)
#' par(opar)
"subtract" = function(plg2) {
stopifnot(isCGALpolygon(plg2) || isCGALpolygonWithHoles(plg2))
if(isCGALpolygon(plg2)) {
xptr2 <- getXPtr(plg2)
plgs <- private[[".CGALpolygon"]]$boolop_subtract(xptr2)
} else {
xptr2 <- getXPtr2(plg2)
plgs <- private[[".CGALpolygon"]]$boolop_subtract2(xptr2)
}
# output
out <- vector("list", length = length(plgs))
for(i in seq_along(plgs)) {
plg <- plgs[[i]]
holes <- plg[["holes"]]
if(length(holes) == 0L) {
out[[i]] <- cgalPolygon$new(vertices = plg[["outer"]])
} else {
out[[i]] <- cgalPolygonWithHoles$new(
outerVertices = plg[["outer"]], holes = holes
)
}
}
out
},
#' @description Symmetric difference of the polygon and another polygon.
#' @param plg2 a \code{cgalPolygon} object or a \code{cgalPolygonWithHoles}
#' object
#' @return A list whose each element is either a \code{cgalPolygon} object
#' or a \code{cgalPolygonWithHoles} object.
#' @examples
#' library(cgalPolygons)
#' # function creating a circle
#' circle <- function(x, y, r) {
#' t <- seq(0, 2, length.out = 100)[-1L]
#' t(c(x, y) + r * rbind(cospi(t), sinpi(t)))
#' }
#' # take two circles
#' plg1 <- cgalPolygon$new(circle(-1, 0, 1.25))
#' plg2 <- cgalPolygon$new(circle(1, 0, 1.25))
#' # symmetric difference
#' plgList <- plg1$symdiff(plg2)
#' plg <- plgList[[1L]]
#' # plot
#' opar <- par(mar = c(0, 0, 0, 0))
#' plot(
#' NULL, xlim = c(-2.6, 2.6), ylim = c(-1.3, 1.3), asp = 1,
#' xlab = NA, ylab = NA, axes = FALSE
#' )
#' plg1$plot(lwd = 2, new = FALSE)
#' plg2$plot(lwd = 2, new = FALSE)
#' plg$plot(list(lwd = 3, col = "red"), col = "white", new = FALSE)
#' par(opar)
"symdiff" = function(plg2) {
stopifnot(isCGALpolygon(plg2) || isCGALpolygonWithHoles(plg2))
if(isCGALpolygonWithHoles(plg2)) {
return(plg2$symdiff(self))
}
xptr2 <- getXPtr(plg2)
plgs <- private[[".CGALpolygon"]]$boolop_symdiff(xptr2)
# output
out <- vector("list", length = length(plgs))
for(i in seq_along(plgs)) {
plg <- plgs[[i]]
holes <- plg[["holes"]]
if(length(holes) == 0L) {
out[[i]] <- cgalPolygon$new(vertices = plg[["outer"]])
} else {
out[[i]] <- cgalPolygonWithHoles$new(
outerVertices = plg[["outer"]], holes = holes
)
}
}
out
},
#' @description Union of the polygon with another polygon.
#' @param plg2 a \code{cgalPolygon} object or a \code{cgalPolygonWithHoles}
#' object
#' @return A list whose each element is either a \code{cgalPolygon} object
#' or a \code{cgalPolygonWithHoles} object.
#' @examples
#' library(cgalPolygons)
#' # function creating a circle
#' circle <- function(x, y, r) {
#' t <- seq(0, 2, length.out = 100)[-1L]
#' t(c(x, y) + r * rbind(cospi(t), sinpi(t)))
#' }
#' # take two circles
#' plg1 <- cgalPolygon$new(circle(-1, 0, 1.25))
#' plg2 <- cgalPolygon$new(circle(1, 0, 1.25))
#' # union
#' plgList <- plg1$union(plg2)
#' plg <- plgList[[1L]]
#' # plot
#' opar <- par(mar = c(0, 0, 0, 0))
#' plot(
#' NULL, xlim = c(-2.6, 2.6), ylim = c(-1.3, 1.3), asp = 1,
#' xlab = NA, ylab = NA, axes = FALSE
#' )
#' plg1$plot(lwd = 2, new = FALSE)
#' plg2$plot(lwd = 2, new = FALSE)
#' plg$plot(lwd = 3, col = "red", new = FALSE)
#' par(opar)
"union" = function(plg2) {
stopifnot(isCGALpolygon(plg2) || isCGALpolygonWithHoles(plg2))
if(isCGALpolygonWithHoles(plg2)) {
return(plg2$union(self))
}
xptr2 <- getXPtr(plg2)
plgs <- private[[".CGALpolygon"]]$boolop_union(xptr2)
# output
out <- vector("list", length = length(plgs))
for(i in seq_along(plgs)) {
plg <- plgs[[i]]
holes <- plg[["holes"]]
if(length(holes) == 0L) {
out[[i]] <- cgalPolygon$new(vertices = plg[["outer"]])
} else {
out[[i]] <- cgalPolygonWithHoles$new(
outerVertices = plg[["outer"]], holes = holes
)
}
}
out
},
#' @description Locate point(s) with respect to the polygon. The polygon
#' must be simple.
#' @param points a numeric matrix with two columns, or a numeric vector
#' of length 2 (for a single point)
#' @return An integer vector with possible values \code{-1}, \code{1}, or
#' \code{0}: value \code{-1} for outside, \code{1} for inside, and
#' \code{0} if the point is on the boundary of the polygon.
#' @examples
#' library(cgalPolygons)
#' ptg <- cgalPolygon$new(pentagram)
#' pt1 <- c(0, 0) # inside
#' pt2 <- c(4, 0) # outside
#' ptg$whereIs(rbind(pt1, pt2))
"whereIs" = function(points) {
if(!is.matrix(points)) {
points <- rbind(points)
}
stopifnot(ncol(points) == 2L)
storage.mode(points) <- "double"
stopifnot(noMissingValue(points))
private[[".CGALpolygon"]]$whereIs(t(points))
}
)
)
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Defines functions getXPtr
getXPtr <- function(cPolygon){
cPolygon[[".__enclos_env__"]][["private"]][[".CGALpolygon"]][["xptr"]]
}
#' @title R6 class to represent a CGAL polygon
#' @description R6 class to represent a CGAL polygon.
#'
#' @importFrom R6 R6Class
#' @export
cgalPolygon <- R6Class(
"cgalPolygon",
lock_class = TRUE,
cloneable = FALSE,
private = list(
".CGALpolygon" = NULL,
".vertices" = NULL
),
public = list(
#' @description Creates a new \code{cgalpolygon} object.
#' @param vertices a numeric matrix with two columns
#' @return A \code{cgalPolygon} object.
#' @examples
#' library(cgalPolygons)
#' ptg <- cgalPolygon$new(pentagram)
#' ptg
"initialize" = function(vertices) {
# one can also initialize from an external pointer, but
# this is hidden to the user
if(inherits(vertices, "externalptr")) {
private[[".CGALpolygon"]] <- CGALpolygon$new(vertices, TRUE)
return(invisible(self))
}
stopifnot(is.matrix(vertices))
stopifnot(ncol(vertices) == 2L)
stopifnot(nrow(vertices) >= 3L)
storage.mode(vertices) <- "double"
stopifnot(noMissingValue(vertices))
private[[".CGALpolygon"]] <- CGALpolygon$new(t(vertices))
private[[".vertices"]] <- vertices
invisible(self)
},
#' @description Print the \code{cgalPolygon} object.
#' @param ... ignored
#' @return No value, just prints some information about the polygon.
"print" = function(...) {
private[[".CGALpolygon"]]$print()
},
#' @description Signed area of the polygon.
#' @return A number, the signed area of the polygon; it is positive if the
#' polygon is counter-clockwise oriented, negative otherwise.
#' @examples
#' library(cgalPolygons)
#' ptg <- cgalPolygon$new(pentagram)
#' ptg$area() # should be 5 / sqrt(130 + 58*sqrt(5))
#' 5 / sqrt(130 + 58*sqrt(5))
"area" = function() {
private[[".CGALpolygon"]]$area()
},
#' @description Bounding box of the polygon.
#' @return A 2x2 matrix giving the lower corner of the bounding box in its
#' first row and the upper corner in its second row.
#' @examples
#' library(cgalPolygons)
#' ptg <- cgalPolygon$new(pentagram)
#' plot(ptg$boundingBox(), asp = 1)
#' polygon(pentagram)
"boundingBox" = function() {
private[[".CGALpolygon"]]$boundingBox()
},
#' @description Decomposition into convex parts. The polygon must be simple
#' and counter-clockwise oriented.
#' @param method the method used: \code{"approx"}, \code{"greene"},
#' or \code{"optimal"}
#' @return A list of matrices; each matrix has two columns and represents
#' a convex polygon.
#' @examples
#' library(cgalPolygons)
#' ptg <- cgalPolygon$new(pentagram)
#' cxparts <- ptg$convexParts()
#' ptg$plot(col = "yellow", lwd = 3)
#' invisible(
#' lapply(cxparts, function(cxpart) {
#' polygon(cxpart, lwd = 2)
#' })
#' )
"convexParts" = function(method = "optimal") {
method <- match.arg(method, c("approx", "greene", "optimal"))
if(method == "approx") {
private[[".CGALpolygon"]]$approxConvexParts()
} else if(method == "greene") {
private[[".CGALpolygon"]]$greeneApproxConvexParts()
} else {
private[[".CGALpolygon"]]$optimalConvexParts()
}
},
#' @description Vertices of the polygon.
#' @return The vertices in a matrix with two columns.
#' @examples
#' library(cgalPolygons)
#' ptg <- cgalPolygon$new(pentagram)
#' ptg$getVertices()
"getVertices" = function() {
private[[".vertices"]]
},
#' @description Intersection of the polygon with another polygon.
#' @param plg2 a \code{cgalPolygon} object or a \code{cgalPolygonWithHoles}
#' object
#' @return A list whose each element is either a \code{cgalPolygon} object
#' or a \code{cgalPolygonWithHoles} object.
#' @examples
#' library(cgalPolygons)
#' # function creating a circle
#' circle <- function(x, y, r) {
#' t <- seq(0, 2, length.out = 100)[-1L]
#' t(c(x, y) + r * rbind(cospi(t), sinpi(t)))
#' }
#' # take two circles
#' plg1 <- cgalPolygon$new(circle(-1, 0, 1.25))
#' plg2 <- cgalPolygon$new(circle(1, 0, 1.25))
#' # intersection
#' plgList <- plg1$intersection(plg2)
#' plg <- plgList[[1L]]
#' # plot
#' opar <- par(mar = c(0, 0, 0, 0))
#' plot(
#' NULL, xlim = c(-2.6, 2.6), ylim = c(-1.3, 1.3), asp = 1,
#' xlab = NA, ylab = NA, axes = FALSE
#' )
#' plg1$plot(lwd = 2, new = FALSE)
#' plg2$plot(lwd = 2, new = FALSE)
#' plg$plot(lwd = 3, col = "red", new = FALSE)
#' par(opar)
"intersection" = function(plg2) {
stopifnot(isCGALpolygon(plg2) || isCGALpolygonWithHoles(plg2))
if(isCGALpolygonWithHoles(plg2)) {
return(plg2$intersection(self))
}
xptr2 <- getXPtr(plg2)
plgs <- private[[".CGALpolygon"]]$boolop_intersection(xptr2)
# output
out <- vector("list", length = length(plgs))
for(i in seq_along(plgs)) {
plg <- plgs[[i]]
holes <- plg[["holes"]]
if(length(holes) == 0L) {
out[[i]] <- cgalPolygon$new(vertices = plg[["outer"]])
} else {
out[[i]] <- cgalPolygonWithHoles$new(
outerVertices = plg[["outer"]], holes = holes
)
}
}
out
},
#' @description Checks whether the polygon is clockwise oriented.
#' @return A Boolean value.
#' @examples
#' library(cgalPolygons)
#' ptg <- cgalPolygon$new(pentagram)
#' ptg$isCWO()
"isCWO" = function() {
private[[".CGALpolygon"]]$isCWO()
},
#' @description Checks whether the polygon is counter-clockwise oriented.
#' @return A Boolean value.
#' @examples
#' library(cgalPolygons)
#' ptg <- cgalPolygon$new(pentagram)
#' ptg$isCCWO()
"isCCWO" = function() {
private[[".CGALpolygon"]]$isCCWO()
},
#' @description Checks whether the polygon is convex.
#' @return A Boolean value.
#' @examples
#' library(cgalPolygons)
#' ptg <- cgalPolygon$new(pentagram)
#' ptg$isConvex()
"isConvex" = function() {
private[[".CGALpolygon"]]$isConvex()
},
#' @description Checks whether the polygon is simple; that means its edges
#' do not intersect (except two consecutive edges which intersect at
#' their common vertex)
#' @return A Boolean value.
#' @examples
#' library(cgalPolygons)
#' ptg <- cgalPolygon$new(pentagram)
#' ptg$isSimple()
"isSimple" = function() {
private[[".CGALpolygon"]]$isSimple()
},
#' @description Minkowski sum of the polygon and another polygon.
#' @param plg2 a \code{cgalPolygon} object or a \code{cgalPolygonWithHoles}
#' object, the polygon to add to the reference polygon
#' @return Either a \code{cgalPolygonWithHoles} object, or, in the case if
#' there is no hole in the Minkowski sum, a \code{cgalPolygon} object.
#' @examples
#' library(cgalPolygons)
#' plg1 <- cgalPolygon$new(decagram)
#' plg2 <- cgalPolygon$new(star)
#' minko <- plg1$minkowskiSum(plg2)
#' minko$plot(lwd = 2, col = "yellowgreen")
"minkowskiSum" = function(plg2) {
stopifnot(isCGALpolygon(plg2) || isCGALpolygonWithHoles(plg2))
if(isCGALpolygonWithHoles(plg2)) {
return(plg2$minkowskiSum(self, method = "convolution"))
}
xptr <- getXPtr(plg2)
msum <- private[[".CGALpolygon"]]$minkowskiC(xptr)
holes <- msum[["holes"]]
nholes <- length(holes)
if(nholes == 0L) {
message("No hole in the Minkowski sum.")
cgalPolygon$new(vertices = msum[["outer"]])
} else {
if(nholes == 1L){
msg <- "There is one hole in the Minkowski sum."
} else {
msg <- sprintf(
"There are %d holes in the Minkowski sum.", nholes
)
}
message(msg)
cgalPolygonWithHoles$new(
outerVertices = msum[["outer"]], holes = holes
)
}
},
#' @description Plot the polygon.
#' @param ... arguments passed to \code{\link[graphics]{polygon}}
#' @param new Boolean, whether to create a new plot
#' @return No returned value, called for side-effect.
#' @importFrom graphics plot polygon
#' @examples
#' library(cgalPolygons)
#' ptg <- cgalPolygon$new(pentagram)
#' ptg$plot(lwd = 3, col = "red")
"plot" = function(..., new = TRUE) {
stopifnot(isBoolean(new))
if(new) {
bbox <- private[[".CGALpolygon"]]$boundingBox()
plot(bbox, type = "n", asp = 1, xlab = NA, ylab = NA, axes = FALSE)
}
polygon(private[[".vertices"]], ...)
invisible(NULL)
},
#' @description Reverse the orientation of the polygon.
#' @return The \code{cgalPolygon} object, invisibly.
#' @examples
#' library(cgalPolygons)
#' ptg <- cgalPolygon$new(pentagram)
#' ptg$isCCWO()
#' ptg$reverseOrientation()
#' ptg$isCCWO()
"reverseOrientation" = function() {
vertices <- private[[".CGALpolygon"]]$reverseOrientation()
private[[".vertices"]] <- vertices
invisible(self)
},
#' @description Difference between the polygon and another polygon.
#' @param plg2 a \code{cgalPolygon} object or a \code{cgalPolygonWithHoles}
#' object
#' @return A list whose each element is either a \code{cgalPolygon} object
#' or a \code{cgalPolygonWithHoles} object.
#' @examples
#' library(cgalPolygons)
#' # function creating a circle
#' circle <- function(x, y, r) {
#' t <- seq(0, 2, length.out = 100)[-1L]
#' t(c(x, y) + r * rbind(cospi(t), sinpi(t)))
#' }
#' # take two circles
#' plg1 <- cgalPolygon$new(circle(-1, 0, 1.25))
#' plg2 <- cgalPolygon$new(circle(1, 0, 1.25))
#' # difference
#' plgList <- plg1$subtract(plg2)
#' plg <- plgList[[1L]]
#' # plot
#' opar <- par(mar = c(0, 0, 0, 0))
#' plot(
#' NULL, xlim = c(-2.6, 2.6), ylim = c(-1.3, 1.3), asp = 1,
#' xlab = NA, ylab = NA, axes = FALSE
#' )
#' plg1$plot(lwd = 2, new = FALSE)
#' plg2$plot(lwd = 2, new = FALSE)
#' plg$plot(lwd = 3, col = "red", new = FALSE)
#' par(opar)
"subtract" = function(plg2) {
stopifnot(isCGALpolygon(plg2) || isCGALpolygonWithHoles(plg2))
if(isCGALpolygon(plg2)) {
xptr2 <- getXPtr(plg2)
plgs <- private[[".CGALpolygon"]]$boolop_subtract(xptr2)
} else {
xptr2 <- getXPtr2(plg2)
plgs <- private[[".CGALpolygon"]]$boolop_subtract2(xptr2)
}
# output
out <- vector("list", length = length(plgs))
for(i in seq_along(plgs)) {
plg <- plgs[[i]]
holes <- plg[["holes"]]
if(length(holes) == 0L) {
out[[i]] <- cgalPolygon$new(vertices = plg[["outer"]])
} else {
out[[i]] <- cgalPolygonWithHoles$new(
outerVertices = plg[["outer"]], holes = holes
)
}
}
out
},
#' @description Symmetric difference of the polygon and another polygon.
#' @param plg2 a \code{cgalPolygon} object or a \code{cgalPolygonWithHoles}
#' object
#' @return A list whose each element is either a \code{cgalPolygon} object
#' or a \code{cgalPolygonWithHoles} object.
#' @examples
#' library(cgalPolygons)
#' # function creating a circle
#' circle <- function(x, y, r) {
#' t <- seq(0, 2, length.out = 100)[-1L]
#' t(c(x, y) + r * rbind(cospi(t), sinpi(t)))
#' }
#' # take two circles
#' plg1 <- cgalPolygon$new(circle(-1, 0, 1.25))
#' plg2 <- cgalPolygon$new(circle(1, 0, 1.25))
#' # symmetric difference
#' plgList <- plg1$symdiff(plg2)
#' plg <- plgList[[1L]]
#' # plot
#' opar <- par(mar = c(0, 0, 0, 0))
#' plot(
#' NULL, xlim = c(-2.6, 2.6), ylim = c(-1.3, 1.3), asp = 1,
#' xlab = NA, ylab = NA, axes = FALSE
#' )
#' plg1$plot(lwd = 2, new = FALSE)
#' plg2$plot(lwd = 2, new = FALSE)
#' plg$plot(list(lwd = 3, col = "red"), col = "white", new = FALSE)
#' par(opar)
"symdiff" = function(plg2) {
stopifnot(isCGALpolygon(plg2) || isCGALpolygonWithHoles(plg2))
if(isCGALpolygonWithHoles(plg2)) {
return(plg2$symdiff(self))
}
xptr2 <- getXPtr(plg2)
plgs <- private[[".CGALpolygon"]]$boolop_symdiff(xptr2)
# output
out <- vector("list", length = length(plgs))
for(i in seq_along(plgs)) {
plg <- plgs[[i]]
holes <- plg[["holes"]]
if(length(holes) == 0L) {
out[[i]] <- cgalPolygon$new(vertices = plg[["outer"]])
} else {
out[[i]] <- cgalPolygonWithHoles$new(
outerVertices = plg[["outer"]], holes = holes
)
}
}
out
},
#' @description Union of the polygon with another polygon.
#' @param plg2 a \code{cgalPolygon} object or a \code{cgalPolygonWithHoles}
#' object
#' @return A list whose each element is either a \code{cgalPolygon} object
#' or a \code{cgalPolygonWithHoles} object.
#' @examples
#' library(cgalPolygons)
#' # function creating a circle
#' circle <- function(x, y, r) {
#' t <- seq(0, 2, length.out = 100)[-1L]
#' t(c(x, y) + r * rbind(cospi(t), sinpi(t)))
#' }
#' # take two circles
#' plg1 <- cgalPolygon$new(circle(-1, 0, 1.25))
#' plg2 <- cgalPolygon$new(circle(1, 0, 1.25))
#' # union
#' plgList <- plg1$union(plg2)
#' plg <- plgList[[1L]]
#' # plot
#' opar <- par(mar = c(0, 0, 0, 0))
#' plot(
#' NULL, xlim = c(-2.6, 2.6), ylim = c(-1.3, 1.3), asp = 1,
#' xlab = NA, ylab = NA, axes = FALSE
#' )
#' plg1$plot(lwd = 2, new = FALSE)
#' plg2$plot(lwd = 2, new = FALSE)
#' plg$plot(lwd = 3, col = "red", new = FALSE)
#' par(opar)
"union" = function(plg2) {
stopifnot(isCGALpolygon(plg2) || isCGALpolygonWithHoles(plg2))
if(isCGALpolygonWithHoles(plg2)) {
return(plg2$union(self))
}
xptr2 <- getXPtr(plg2)
plgs <- private[[".CGALpolygon"]]$boolop_union(xptr2)
# output
out <- vector("list", length = length(plgs))
for(i in seq_along(plgs)) {
plg <- plgs[[i]]
holes <- plg[["holes"]]
if(length(holes) == 0L) {
out[[i]] <- cgalPolygon$new(vertices = plg[["outer"]])
} else {
out[[i]] <- cgalPolygonWithHoles$new(
outerVertices = plg[["outer"]], holes = holes
)
}
}
out
},
#' @description Locate point(s) with respect to the polygon. The polygon
#' must be simple.
#' @param points a numeric matrix with two columns, or a numeric vector
#' of length 2 (for a single point)
#' @return An integer vector with possible values \code{-1}, \code{1}, or
#' \code{0}: value \code{-1} for outside, \code{1} for inside, and
#' \code{0} if the point is on the boundary of the polygon.
#' @examples
#' library(cgalPolygons)
#' ptg <- cgalPolygon$new(pentagram)
#' pt1 <- c(0, 0) # inside
#' pt2 <- c(4, 0) # outside
#' ptg$whereIs(rbind(pt1, pt2))
"whereIs" = function(points) {
if(!is.matrix(points)) {
points <- rbind(points)
}
stopifnot(ncol(points) == 2L)
storage.mode(points) <- "double"
stopifnot(noMissingValue(points))
private[[".CGALpolygon"]]$whereIs(t(points))
}
)
)
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