Added new function geom_curve

DESCRIPTION

@@ -96,6 +96,7 @@ Collate:
     'geom-blank.r'
     'geom-boxplot.r'
     'geom-crossbar.r'
+    'geom-curve.r'
     'geom-defaults.r'
     'geom-dotplot.r'
     'geom-error.r'

NAMESPACE

@@ -224,6 +224,7 @@ export(geom_boxplot)
 export(geom_contour)
 export(geom_count)
 export(geom_crossbar)
+export(geom_curve)
 export(geom_density)
 export(geom_density2d)
 export(geom_dotplot)

NEWS

@@ -1,5 +1,7 @@
 * New `theme_void()`, which is completely empty. Useful for plots with non
   standard coordinates or for producing numerical drawings with R. (@jiho, #976)
+* Added new function geom_curve to add curved lines to plot (similar to
+  geom_segment to add straight lines). (@veraanadi, #1088)
 
 * Create correct legend for continuous color even if there is only one color
   (@krlmlr, #943)

R/geom-curve.r

@@ -0,0 +1,64 @@
+#' Single curved line segments.
+#'
+#' @section Aesthetics:
+#' \Sexpr[results=rd,stage=build]{ggplot2:::rd_aesthetics("geom", "curve")}
+#'
+#' @inheritParams grid::curveGrob
+#' @inheritParams geom_point
+#' @inheritParams geom_segment
+#'
+#' @seealso \code{\link{geom_segment}}, \code{\link{geom_path}} and \code{\link{geom_line}} for multi-
+#' segment lines and paths.
+#' @export
+#' @examples
+#' # Adding curve segments
+#' library(grid) # needed for arrow function
+#' b <- ggplot(mtcars, aes(wt, mpg)) + geom_point()
+#' b + geom_curve(aes(x = 2, y = 15, xend = 2, yend = 25), curvature = 0.2)
+#' b + geom_curve(aes(x = 2, y = 15, xend = 3, yend = 15), ncp = 2)
+#' b + geom_curve(aes(x = 5, y = 30, xend = 3.5, yend = 25), arrow = arrow(length = unit(0.5, "cm")))
+
+
+geom_curve <- function (mapping = NULL, data = NULL, stat = "identity", position = "identity",
+                        curvature = 1, angle = 90, ncp = 1, arrow = NULL, lineend = "butt",
+                        na.rm = FALSE, ...) {
+
+  GeomCurve$new(mapping = mapping, data = data, stat = stat,
+                position = position, arrow = arrow, curvature = curvature, angle = angle,
+                ncp = ncp, lineend = lineend, na.rm = na.rm, ...)
+}
+
+GeomCurve <- proto(Geom, {
+  objname <- "curve"
+
+    draw <- function(., data, scales, coordinates, curvature, angle, ncp,
+                     arrow, lineend, na.rm, ...) {
+
+    data <- remove_missing(data, na.rm = na.rm,
+                           c("x", "y", "xend", "yend", "linetype", "size", "shape"),
+                           name = "geom_curve")
+
+    if (empty(data)) return(zeroGrob())
+
+    if (is.linear(coordinates)) {
+      return(with(coord_transform(coordinates, data, scales),
+                  curveGrob(x, y, xend, yend, default.units="native",
+                            curvature=curvature, angle=angle, ncp=ncp,
+                            square = FALSE, squareShape = 1,
+                            inflect = FALSE, open = TRUE,
+                            gp = gpar(col=alpha(colour, alpha), lwd=size * .pt,
+                                      lty=linetype, lineend = lineend),
+                            arrow = arrow)
+      ))
+    }
+    warning("geom_curve is not implemented for non-linear coordinates")
+    return(zeroGrob())
+  }
+
+
+  default_stat <- function(.) StatIdentity
+  required_aes <- c("x", "y", "xend", "yend")
+  default_aes <- function(.) aes(colour="black", size=0.5, linetype=1, alpha = NA)
+  guide_geom <- function(.) "path"
+
+})

man/geom_bar.Rd

@@ -145,7 +145,7 @@ m + geom_bar()
 }
 }
 \seealso{
-\code{\link{stat_bin}} for more details of the binning alogirithm,
+\code{\link{stat_bin}} for more details of the binning algorithm,
   \code{\link{position_dodge}} for creating side-by-side barcharts,
   \code{\link{position_stack}} for more info on stacking,
 }

man/geom_curve.Rd

@@ -0,0 +1,67 @@
+% Generated by roxygen2 (4.1.1): do not edit by hand
+% Please edit documentation in R/geom-curve.r
+\name{geom_curve}
+\alias{geom_curve}
+\title{Single curved line segments.}
+\usage{
+geom_curve(mapping = NULL, data = NULL, stat = "identity",
+  position = "identity", curvature = 1, angle = 90, ncp = 1,
+  arrow = NULL, lineend = "butt", na.rm = FALSE, ...)
+}
+\arguments{
+\item{mapping}{The aesthetic mapping, usually constructed with
+\code{\link{aes}} or \code{\link{aes_string}}. Only needs to be set
+at the layer level if you are overriding the plot defaults.}
+
+\item{data}{A layer specific dataset - only needed if you want to override
+the plot defaults.}
+
+\item{stat}{The statistical transformation to use on the data for this
+layer.}
+
+\item{position}{The position adjustment to use for overlapping points
+on this layer}
+
+\item{curvature}{A numeric value giving the amount of curvature.
+    Negative values produce left-hand curves, positive values
+    produce right-hand curves, and zero produces a straight line.}
+
+\item{angle}{A numeric value between 0 and 180,
+    giving an amount to skew the control
+    points of the curve.  Values less than 90 skew the curve towards
+    the start point and values greater than 90 skew the curve
+    towards the end point.}
+
+\item{ncp}{The number of control points used to draw the curve.
+    More control points creates a smoother curve.}
+
+\item{arrow}{A list describing arrow heads to place at either end
+    of the curve, as produced by the \code{arrow} function.}
+
+\item{lineend}{Line end style (round, butt, square)}
+
+\item{na.rm}{If \code{FALSE} (the default), removes missing values with
+a warning.  If \code{TRUE} silently removes missing values.}
+
+\item{...}{Arguments to be passed to \code{curveGrob}.}
+}
+\description{
+Single curved line segments.
+}
+\section{Aesthetics}{
+
+\Sexpr[results=rd,stage=build]{ggplot2:::rd_aesthetics("geom", "curve")}
+}
+\examples{
+# Adding curve segments
+library(grid) # needed for arrow function
+b <- ggplot(mtcars, aes(wt, mpg)) + geom_point()
+b + geom_curve(aes(x = 2, y = 15, xend = 2, yend = 25), curvature = 0.2)
+b + geom_curve(aes(x = 2, y = 15, xend = 3, yend = 15), ncp = 2)
+b + geom_curve(aes(x = 5, y = 30, xend = 3.5, yend = 25), arrow = arrow(length = unit(0.5, "cm")))
+}
+\seealso{
+\code{\link{geom_segment}}, \code{\link{geom_path}} and \code{\link{geom_line}} for multi-
+segment lines and paths.
+}
+

man/geom_density2d.Rd

@@ -36,7 +36,7 @@ include aesthetics whose values you want to set, not map. See
 \code{\link{layer}} for more details.}
 }
 \description{
-Perform a 2D kernel density estimatation using kde2d and display the
+Perform a 2D kernel density estimation using kde2d and display the
 results with contours.
 }
 \details{