Extra Coordinate Systems, 'Geoms', Statistical Transformations, Scales and Fonts for 'ggplot2'
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#' @title Draw spikelines on a plot
#' @description Segment reference lines that originate at an point
#' @inheritParams ggplot2::geom_line
#' @examples
#'
#' mtcars$name <- rownames(mtcars)
#'
#' p <- ggplot(data = mtcars, aes(x=mpg,y=disp)) + geom_point()
#'
#' p + geom_spikelines(data = mtcars[mtcars$carb==4,],linetype = 2)
#'
#' p + geom_spikelines(data = mtcars[mtcars$carb==4,],aes(colour = factor(gear)), linetype = 2)
#'
#' \dontrun{
#' require(ggrepel)
#' p + geom_spikelines(data = mtcars[mtcars$carb==4,],aes(colour = factor(gear)), linetype = 2) +
#' ggrepel::geom_label_repel(data = mtcars[mtcars$carb==4,],aes(label = name))
#' }
#'
#' @rdname geom_spikelines
#' @author Jonathan Sidi
#' @export
geom_spikelines <- function(mapping = NULL, data = NULL,
stat = "identity", position = "identity",
...,
arrow = NULL,
lineend = "butt",
linejoin = "round",
na.rm = FALSE,
show.legend = NA,
inherit.aes = TRUE) {
layer(
data = data,
mapping = mapping,
stat = stat,
geom = GeomSpikelines,
position = position,
show.legend = show.legend,
inherit.aes = inherit.aes,
params = list(
arrow = arrow,
lineend = lineend,
linejoin = linejoin,
na.rm = na.rm,
...
)
)
}
#' @rdname ggalt-ggproto
#' @format NULL
#' @usage NULL
#' @export
GeomSpikelines <- ggproto("GeomSpikelines", Geom,
required_aes = c("x", "y"),
non_missing_aes = c("linetype", "size", "shape"),
default_aes = aes(colour = "black", size = 0.5, linetype = 1, alpha = NA),
draw_panel = function(data, panel_params, coord, arrow = NULL,
lineend = "butt", linejoin = "round", na.rm = FALSE) {
data1 <- data
data2 <- data
data1$xend <- data$x
data1$yend <- data$y
data1$y <- 0
data2$xend <- data$x
data2$yend <- data$y
data2$x <- 0
data <- rbind(data1,data2)
data <- remove_missing(data, na.rm = na.rm,
c("x", "y", "linetype", "size", "shape"),
name = "geom_spikelines")
if (empty(data)) return(zeroGrob())
if (coord$is_linear()) {
coord <- coord$transform(data, panel_params)
ret <- grid::segmentsGrob(coord$x, coord$y, coord$xend, coord$yend,
default.units = "native",
gp = grid::gpar(
col = alpha(coord$colour, coord$alpha),
fill = alpha(coord$colour, coord$alpha),
lwd = coord$size * .pt,
lty = coord$linetype,
lineend = lineend,
linejoin = linejoin
),
arrow = arrow
)
return(ret)
}
data$group <- 1:nrow(data)
starts <- subset(data, select = c(-xend, -yend))
ends <- plyr::rename(subset(data, select = c(-x, -y)), c("xend" = "x", "yend" = "y"),
warn_missing = FALSE)
pieces <- rbind(starts, ends)
pieces <- pieces[order(pieces$group),]
GeomPath$draw_panel(pieces, panel_params, coord, arrow = arrow,
lineend = lineend)
},
draw_key = draw_key_path
)
empty <- function (df)
{
is.null(df) || nrow(df) == 0 || ncol(df) == 0
}