straightarrow {diagram}

adds straight arrow between two points

Description

Plots straight line between two points

adds an arrowhead at a certain distance.

Usage

straightarrow(from, to, lwd = 2, lty = 1, lcol = "black", 
              arr.col = lcol, arr.pos = 0.5, 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

arrow color.

arr.pos

relative position of arrowhead.

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.

Details

a straight arrow is drawn between the points '(from, to)' The position of the arrowhead, is set with arr.pos, a value between 0(start point) and 1(endpoint)

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.

Value

coordinates (x,y) where arrowhead is drawn

Author(s)

Karline Soetaert <[e-mail]>

See Also

bentarrow, segmentarrow, curvedarrow selfarrow, splitarrow, treearrow,

arrows: the comparable R function,

Arrows: more complicated arrow function from package shape.

Examples

openplotmat(main = "straightarrow")

pos <- coordinates(c(2, 3, 1))

for (i in 1:5) 
  straightarrow(from = pos[i, ], to = pos[i+1, ], arr.pos = 0.5)

straightarrow(from = pos[6, ], to = pos[6, ] + c(0.3, 0.), 
              arr.type = "T", arr.pos = 1, arr.lwd = 3)    

for (i in 1:6) 
  textrect(pos[i, ], lab = LETTERS[i], radx = 0.05)