straightarrow() R function from [diagram]

adds straight arrow between two points

Plots straight line between two points

adds an arrowhead at a certain distance.


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 .

Returns

coordinates (x,y) where arrowhead is drawn

Author(s)

Karline Soetaert karline.soetaert@nioz.nl

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)

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 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.

straightarrow function