grid.bezier
Draw a Bezier Curve
Description
These functions create and draw Bezier Curves (a curve drawn relative to 4 control points).
Usage
grid.bezier(...) bezierGrob(x = c(0, 0.5, 1, 0.5), y = c(0.5, 1, 0.5, 0), id = NULL, id.lengths = NULL, default.units = "npc", arrow = NULL, name = NULL, gp = gpar(), vp = NULL)
Arguments
x | A numeric vector or unit object specifying x-locations of spline control points. |
y | A numeric vector or unit object specifying y-locations of spline control points. |
id | A numeric vector used to separate locations in |
id.lengths | A numeric vector used to separate locations in |
default.units | A string indicating the default units to use if |
arrow | A list describing arrow heads to place at either end of the bezier, as produced by the |
name | A character identifier. |
gp | An object of class |
vp | A Grid viewport object (or NULL). |
... | Arguments to be passed to |
Details
Both functions create a beziergrob (a graphical object describing a Bezier curve), but only grid.bezier
draws the Bezier curve.
A Bezier curve is a line drawn relative to 4 control points.
Missing values are not allowed for x
and y
(i.e., it is not valid for a control point to be missing).
The curve is currently drawn using an approximation based on X-splines.
Value
A grob object.
See Also
Examples
x <- c(0.2, 0.2, 0.4, 0.4) y <- c(0.2, 0.4, 0.4, 0.2) grid.newpage() grid.bezier(x, y) grid.bezier(c(x, x + .4), c(y + .4, y + .4), id=rep(1:2, each=4)) grid.segments(.4, .6, .6, .6) grid.bezier(x, y, gp=gpar(lwd=3, fill="black"), arrow=arrow(type="closed"), vp=viewport(x=.9))
Copyright (©) 1999–2012 R Foundation for Statistical Computing.
Licensed under the GNU General Public License.