#' Define simple shapes for line capping
#'
#' This set of functions makes it easy to define shapes at the terminal points
#' of edges that are used to shorten the edges. The shapes themselves are not
#' drawn, but the edges will end at the boundary of the shape rather than at
#' the node position. This is especially relevant when drawing arrows at the
#' edges as the arrows will be partly obscured by the node unless the edge is
#' shortened. Edge shortening is dynamic and will update as the plot is resized,
#' making sure that the capping remains at an absolute distance to the end
#' point.
#'
#' @details
#' \code{geometry} is the base constructor, while the rest are helpers to save
#' typing. \code{circle} creates circles width a given radius, \code{square}
#' creates squares at a given side length, \code{ellipsis} creates ellipses with
#' given a and b values (width and height radii), and \code{rectangle} makes
#' rectangles of a given width and height. label_rect is a helper that, given
#' a list of strings and potentially formatting options creates a rectangle that
#' encloses the string.
#'
#' @param type The type of geometry to use. Currently \code{'circle'} and
#' \code{'rect'} is supported.
#'
#' @param width,height,length,radius,a,b The dimensions of the shape.
#'
#' @param unit,width_unit,height_unit,a_unit,b_unit The unit for the numbers
#' given.
#'
#' @return A geometry object encoding the specified shape.
#'
#' @examples
#' geometry(c('circle', 'rect', 'rect'), 1:3, 3:1)
#'
#' circle(1:4, 'mm')
#'
#' label_rect(c('some', 'different', 'words'), fontsize = 18)
#'
#' @export
#'
geometry <- function(type = 'circle', width = 1, height = width,
width_unit = 'cm', height_unit = width_unit) {
l <- max(length(type), length(width), length(height))
g <- rep(type, length.out = l)
g_na <- is.na(g)
width <- rep(width, length.out = l)
width[g_na] <- 0
height <- rep(height, length.out = l)
height[g_na] <- 0
uwidth <- rep(width_unit, length.out = l)
uheight <- rep(height_unit, length.out = l)
g[g_na] <- 'circle'
attributes(g) <- list(width = width, uwidth = uwidth, height = height,
uheight = uheight, class = 'geometry')
g
}
#' @rdname geometry
#'
#' @export
circle <- function(radius = 1, unit = 'cm') {
geometry('circle', width = radius*2, width_unit = unit)
}
#' @rdname geometry
#'
#' @export
square <- function(length = 1, unit = 'cm') {
geometry('rect', width = length, width_unit = unit)
}
#' @rdname geometry
#'
#' @export
ellipsis <- function(a = 1, b = 1, a_unit = 'cm', b_unit = a_unit) {
geometry('circle', width = a*2, height = b*2, width_unit = a_unit,
height_unit = b_unit)
}
#' @rdname geometry
#'
#' @export
rectangle <- function(width = 1, height = 1, width_unit = 'cm',
height_unit = width_unit) {
geometry('rect', width = width, height = height, width_unit = width_unit,
height_unit = height_unit)
}
#' @rdname geometry
#'
#' @param label The text to be enclosed
#'
#' @param padding extra size to be added around the text using the
#' \code{\link[ggplot2]{margin}} function
#'
#' @param ... Passed on to \code{\link[grid]{gpar}}
#'
#' @export
#' @importFrom grid convertWidth convertHeight textGrob grobWidth grobHeight
label_rect <- function(label, padding = margin(1,1,1.5,1,'mm'), ...) {
grobs <- lapply(label, textGrob, gp = gpar(...))
width <- abs_width(grobs)
height <- abs_height(grobs)
width <- width + sum(convertWidth(padding[c(2, 4)], 'cm', TRUE))
height <- height + sum(convertHeight(padding[c(1, 3)], 'cm', TRUE))
geometry('rect', width = width, height = height)
}
#' @rdname geometry
#'
#' @param x An object to test for geometry inheritance
#'
#' @export
is.geometry <- function(x) inherits(x, 'geometry')
#' @export
length.geometry <- function(x) length(unclass(x))
#' @export
`[.geometry` <- function(x, i, ...) {
structure(
unclass(x)[i],
width = attr(x, 'width')[i],
height = attr(x, 'height')[i],
uwidth = attr(x, 'uwidth')[i],
uheight = attr(x, 'uheight')[i],
class = 'geometry'
)
}
#' @export
`[<-.geometry` <- function(x, ..., value) {
stopifnot(is.geometry(value))
type <- unclass(x)
type[...] <- unclass(value)
width <- attr(x, 'width')
width[...] <- attr(value, 'width')
height <- attr(x, 'height')
height[...] <- attr(value, 'height')
uwidth <- attr(x, 'uwidth')
uwidth[...] <- attr(value, 'uwidth')
uheight <- attr(x, 'uheight')
uheight[...] <- attr(value, 'uheight')
structure(
type,
width = width,
height = height,
uwidth = uwidth,
uheight = uheight,
class = 'geometry'
)
}
#' @export
format.geometry <- function(x, ...) {
paste0(unclass(x), '(', attr(x, 'width'), attr(x, 'uwidth'),
', ', attr(x, 'height'), attr(x, 'uheight'), ')')
}
#' @export
print.geometry <- function(x, ...) {
print(format(x, ...))
}
#' @export
rep.geometry <- function(x, ...) {
i <- rep(seq_along(x), ...)
x[i]
}
#' @export
as.data.frame.geometry <- function(x, row.names = NULL, optional = FALSE, ...) {
nrows <- length(x)
if (!(is.null(row.names) || (is.character(row.names) && length(row.names) ==
nrows))) {
stop(gettextf("'row.names' is not a character vector of length %d -- omitting it. Will be an error!",
nrows), call. = FALSE)
row.names <- NULL
}
if (is.null(row.names)) {
if (nrows == 0L) {
row.names <- character()
} else {
row.names <- .set_row_names(nrows)
}
}
structure(list(x), row.names = row.names, class = 'data.frame')
}
#' @export
c.geometry <- function(...) {
geometries <- list(...)
base <- do.call(c, lapply(geometries, unclass))
g_attr <- do.call(Map, c(list(f = c), lapply(geometries, attributes)))
g_attr$class <- 'geometry'
attributes(base) <- g_attr
base
}
#' @export
is.na.geometry <- function(x) {
is.na(unclass(x))
}
geo_type <- function(x) {
stopifnot(is.geometry(x))
unclass(x)
}
geo_width <- function(x) {
stopifnot(is.geometry(x))
unit(attr(x, 'width'), attr(x, 'uwidth'))
}
geo_height <- function(x) {
stopifnot(is.geometry(x))
unit(attr(x, 'height'), attr(x, 'uheight'))
}
#' @importFrom grid convertHeight grobHeight
abs_height <- function(grobs) {
sapply(grobs, function(g) convertHeight(grobHeight(g), 'cm', TRUE))
}
#' @importFrom grid convertWidth grobWidth
abs_width <- function(grobs) {
sapply(grobs, function(g) convertWidth(grobWidth(g), 'cm', TRUE))
}
#' Define default scale type for geometry
#'
#' This functions is quite useless as geometry is not meant to be scaled, but it
#' is a requirement for ggplot2 to handle it correctly.
#'
#' @export
#'
#' @keywords internal
scale_type.geometry <- function(x) 'identity'
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