curvedarrow() R function from [diagram]

adds curved arrow between two points

Connects two points with an ellipsoid line and adds an arrowhead at a certain distance


curvedarrow(from, to, lwd = 2, lty = 1, lcol = "black", 
            arr.col = lcol, arr.pos = 0.5, curve = 1, dr = 0.01, 
            endhead = FALSE, segment = c(0, 1), ...)

Arguments

from: coordinates (x,y) of the point from which to draw arrow.
to: coordinates (x,y) of the point to which to draw arrow.
lwd: line width.
lty: line type.
lcol: line color.
arr.col: arrowhead color.
arr.pos: relative position of arrowhead.
curve: relative size of curve (fraction of points distance) - see details.
dr: size of segments, in radians, to draw ellipse (decrease for smoother).
endhead: if TRUE: the arrow line stops at the arrowhead; default = FALSE.
segment: if not c(0,1): then the arrow line will cover only part of the requested path, e.g. if segment = c(0.2,0.8), it will start 0.2 from from and till 0.8.
...: arguments passed to function Arrows.

Returns

default: coordinates (x,y) where arrowhead is drawn.

Author(s)

Karline Soetaert karline.soetaert@nioz.nl

Examples


openplotmat(main = "curvedarrow")

pos <- coordinates(pos = 4, my = 0.2)
text(pos, LETTERS[1:4], cex = 2)

for (i in 1:3) 
  curvedarrow(from = pos[1, ] + c(0,-0.05), to = pos[i+1, ] + c(0,-0.05),
              curve = 0.5, arr.pos = 1)
for (i in 1:3) 
  curvedarrow(from = pos[1, ] + c(0, 0.05), to = pos[i+1, ] + c(0, 0.05),
              curve = -0.25, arr.adj = 1, arr.pos = 0.5, 
              arr.type = "triangle", arr.col = "blue")

Details

A curved arrow is drawn between two points '(from, to)'

The position of the arrowhead, is set with arr.pos, a value between 0(start point) and 1(endpoint)

The line curvature is set with curve which expresses the ellipse radius as a fraction of the distance between the two points. For instance, curve=0.5 will draw an ellepse with small radius half of a circle.

The type of the arrowhead is set with arr.type which can take the values:

"none" : skips the drawing of arrows.
"simple" : uses comparable R function arrows.
"triangle": uses filled triangle.
"curved" : draws arrowhead with curved edges.
"circle" : draws circular head.
"ellipse" : draws ellepsoid head.
"T" : draws T-shaped (blunt) head.

The size of the arrow head can be specified with the arguments arr.length and arr.width.

See Arrowhead from package shape for details on arrow head

curvedarrow function