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#' Create a polygon \code{geom}
#'
#' Create any (regular) polygon geometry (of class \code{\link{geom}}) either by
#' specifying anchor values or by sketching it.
#' @param anchor [\code{geom(1)}|\code{data.frame(1)}]\cr Object to derive the
#' \code{geom} from. It must include column names \code{x}, \code{y} and
#' optionally a custom \code{fid}.
#' @param window [\code{data.frame(1)}]\cr in case the reference window deviates
#' from the bounding box of \code{anchor} (minimum and maximum values),
#' specify this here.
#' @param features [\code{integerish(1)}]\cr number of polygons to create.
#' @param vertices [\code{integerish(.)}]\cr number of vertices per polygon;
#' will be recycled if it does not have as many elements as specified in
#' \code{features}.
#' @param regular [\code{logical(1)}]\cr should the polygon be regular, i.e.
#' point symmetric (\code{TRUE}) or should the vertices be selected as
#' provided by \code{anchor} (\code{FALSE}, default)?
#' @param ... [various]\cr graphical parameters to \code{\link{gt_locate}}, in
#' case points are sketched; see \code{\link[grid]{gpar}}
#' @details The argument \code{anchor} indicates how the geom is created:
#' \itemize{ \item if \code{anchor} is set, the geom is created parametrically
#' from the points given in \code{anchor}, \item if it is not set either
#' \code{window} or a default window between 0 and 1 is opened to sketch the
#' geom.}
#'
#' The argument \code{regular} determines how the vertices provided in
#' \code{anchor} or via \code{template} are transformed into a polygon:
#' \itemize{ \item if \code{regular = FALSE} the resulting polygon is created
#' from all vertices in \code{anchor}, \item if \code{regular = TRUE}, only
#' the first two vertices are considered, as center and indicating the
#' distance to the (outer) radius.}
#' @return A \code{geom}.
#' @family geometry shapes
#' @examples
#' # 1. create a polygon programmatically
#' coords <- data.frame(x = c(0, 40, 40, 0),
#' y = c(0, 0, 40, 40))
#'
#' # if no window is set, the bounding box will be set as window
#' aGeom <- gs_polygon(anchor = coords)
#' visualise(aGeom)
#'
#' # derive a regular polygon from the coordinates
#' aPolygon <- gs_polygon(anchor = coords, vertices = 6, regular = TRUE)
#' visualise(aPolygon, linecol = "green")
#' visualise(aGeom, new = FALSE)
#'
#' # the vertices are plottet relative to the window
#' window <- data.frame(x = c(-50, 50),
#' y = c(-50, 50))
#' aPolygon <- setWindow(x = aPolygon, to = window)
#' visualise(aPolygon, fillcol = "deeppink")
#'
#' # using a geom as anchor retains its properties (such as the window)
#' aRectangle <- gs_rectangle(anchor = aPolygon)
#' visualise(aRectangle, new = FALSE)
#'
#' # 2. sketch a hexagon
#' if(dev.interactive()){
#' aHexagon <- gs_hexagon(features = 1)
#' visualise(aHexagon, linecol = "deeppink", linetype = 2, new = FALSE)
#' }
#' @importFrom stats dist
#' @importFrom checkmate testDataFrame assertNames testClass assertDataFrame
#' testTRUE testNull testClass assertIntegerish assertLogical assert
#' @importFrom tibble tibble add_row
#' @importFrom dplyr bind_cols bind_rows filter
#' @importFrom rlang !!
#' @export
gs_polygon <- function(anchor = NULL, window = NULL, features = 1, vertices = 3,
regular = FALSE, ...){
# check arguments
anchor <- .testAnchor(x = anchor)
theWindow <- .testWindow(x = window)
assertIntegerish(x = features, len = 1, lower = 1)
assertIntegerish(x = vertices, min.len = 1, lower = 2, any.missing = FALSE, null.ok = TRUE)
assertLogical(x = regular)
if(!is.null(anchor)){
if(anchor$type == "geom"){
hist <- paste0("object was cast to 'polygon' geom.")
if(getType(x = anchor$obj)[1] == "point"){
features <- length(unique(anchor$obj@feature$gid))
} else {
features <- length(unique(anchor$obj@feature$fid))
}
projection <- getCRS(x = anchor$obj)
} else if(anchor$type == "df"){
hist <- paste0("object was created as 'polygon' geom.")
if("fid" %in% names(anchor$obj)){
features <- length(unique(anchor$obj$fid))
}
projection <- NA
}
}
# recycle vertices to match the number of features
if(length(vertices) != features){
vertices <- rep(vertices, length.out = features)
}
thePoints <- theFeatures <- theGroups <- NULL
for(i in 1:features){
if(!is.null(anchor)){
if(anchor$type == "geom"){
hist <- paste0("object was cast to 'polygon' geom.")
theHistory <- c(getHistory(x = anchor$obj), list(hist))
if(is.null(theWindow)){
theWindow <- anchor$obj@window
}
if(getType(x = anchor$obj)[1] == "point"){
tempAnchor <- gt_filter(obj = anchor$obj, gid == !!i)
} else {
tempAnchor <- gt_filter(obj = anchor$obj, gid == !!i)
}
tempPoints <- getPoints(tempAnchor)
tempFeatures <- getFeatures(tempAnchor)
tempGroups <- getGroups(tempAnchor)
tempPoints <- left_join(tempPoints, tempFeatures, by = "fid")
tempPoints <- select(mutate(tempPoints, fid = gid), -gid)
tempFeatures <- tibble(fid = unique(tempPoints$fid), gid = unique(tempFeatures$gid))
if(dim(tempAnchor@point)[1] < 3){
stop(paste0("a polygon geom must have at least 3 points per 'fid'."))
}
} else if(anchor$type == "df"){
theHistory <- list(paste0("object was created as 'polygon' geom."))
if(is.null(theWindow)){
theWindow = tibble(x = c(min(anchor$obj$x), max(anchor$obj$x)),
y = c(min(anchor$obj$y), max(anchor$obj$y)))
}
if("fid" %in% names(anchor$obj)){
tempPoints <- anchor$obj[anchor$obj$fid == i, ]
} else {
tempPoints <- anchor$obj
tempPoints <- bind_cols(tempPoints, fid = rep(i, length.out = length(anchor$obj$x)))
}
tempFeatures <- tibble(fid = i, gid = 1)
tempGroups <- tibble(gid = 1)
}
} else {
if(regular){
clicks <- 2
} else {
clicks <- vertices[i]
}
theHistory <- list(paste0("object was created as 'polygon' geom."))
# first, ensure that a plot is available, otherwise make one
if(is.null(dev.list())){
if(is.null(theWindow)){
theWindow <- tibble(x = c(0, 1), y = c(0, 1))
}
visualise(window = theWindow)
} else {
extentGrobMeta <- grid.get(gPath("extentGrob"))
theWindow <- tibble(x = c(0, as.numeric(extentGrobMeta$width)) + as.numeric(extentGrobMeta$x),
y = c(0, as.numeric(extentGrobMeta$height)) + as.numeric(extentGrobMeta$y))
}
message(paste0("please click ", clicks, " vertices."))
tempAnchor <- gt_locate(samples = clicks)
tempAnchor <- .testPoints(x = tempAnchor)
if(is.null(tempAnchor)){
tempAnchor <- gs_random(type = "polygon", vertices = vertices)
tempAnchor <- tempAnchor@point
}
tempPoints <- tibble(fid = i, x = tempAnchor$x, y = tempAnchor$y)
tempFeatures = tibble(fid = i, gid = 1)
tempGroups = tibble(gid = 1)
projection <- NA
}
openingAngle <- atan((tempPoints$x[1] - tempPoints$x[2]) / (tempPoints$y[1] - tempPoints$y[2])) * 180 / pi
# build a regular geometry
if(regular){
# trigonometry
angle <- 360/vertices[i]
angles <- seq(from = 90, to = 360-angle+90, by = angle) - openingAngle
radius <- dist(tempPoints[c(1:2),])
cx <- tempPoints$x[1] + radius*cos(.rad(angles))
cy <- tempPoints$y[1] + radius*sin(.rad(angles))
theNodes <- tibble(x = cx, y = cy, fid = i)
theWindow <- .updateWindow(input = theNodes, window = theWindow)
} else{
theNodes <- tempPoints[c("x", "y", "fid")]
}
theNodes <- .updateVertices(input = theNodes)
thePoints <- bind_rows(thePoints, theNodes)
theFeatures <- bind_rows(theFeatures, tempFeatures)
theGroups <- bind_rows(theGroups, tempGroups)
}
theGeom <- new(Class = "geom",
type = "polygon",
point = thePoints,
feature = theFeatures,
group = theGroups,
window = theWindow,
crs = as.character(projection),
history = theHistory)
invisible(theGeom)
}
#' @describeIn gs_polygon wrapper of gs_polygon where \code{vertices = 3} and
#' \code{regular = TRUE}.
#' @export
gs_triangle <- function(anchor = NULL, window = NULL, features = 1, ...){
theGeom <- gs_polygon(anchor = anchor, window = window, features = features, vertices = 3, regular = TRUE, ...)
invisible(theGeom)
}
#' @describeIn gs_polygon wrapper of gs_polygon where \code{vertices = 4} and
#' \code{regular = TRUE}.
#' @export
gs_square <- function(anchor = NULL, window = NULL, features = 1, ...){
theGeom <- gs_polygon(anchor = anchor, window = window, features = features, vertices = 4, regular = TRUE, ...)
invisible(theGeom)
}
#' @describeIn gs_polygon wrapper of gs_polygon where \code{vertices = 2},
#' \code{regular = FALSE} and the two complementing corners are derived from
#' the two given opposing corners.
#' @export
gs_rectangle <- function(anchor = NULL, window = NULL, features = 1, ...){
theGeom <- gs_polygon(anchor = anchor, window = window, features = features, vertices = 2, ...)
outTable <- NULL
for(i in seq_along(theGeom@feature$fid)){
geomSubset <- gt_filter(theGeom, fid == !!i)
temp <- getExtent(geomSubset)
temp <- tibble(x = c(rep(temp$x, each = 2), temp$x[1]),
y = c(temp$y, rev(temp$y), temp$y[1]),
fid = i)
outTable <- bind_rows(outTable, temp)
}
theGeom@point <- outTable
invisible(theGeom)
}
#' @describeIn gs_polygon wrapper of gs_polygon where \code{vertices = 6} and
#' \code{regular = TRUE}.
#' @export
gs_hexagon <- function(anchor = NULL, window = NULL, features = 1, ...){
theGeom <- gs_polygon(anchor = anchor, window = window, features = features, vertices = 6, regular = TRUE, ...)
invisible(theGeom)
}
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