segmentarrow() R function from [diagram]

adds 3-segmented arrow between two points.

Connects two points with 3 segments (default = left-vertical-right) and adds an arrowhead on one of the segments at a certain distance


segmentarrow(from, to, lwd = 2, lty = 1, lcol = "black", 
             arr.col = lcol, arr.side = 2, arr.pos = 0.5, 
             path = "LVR", dd = 0.5, ...)

Arguments

from: coordinates (x,y) of point from which to draw arrow.
to: coordinates (x,y) of point to which to draw arrow.
lwd: line width.
lty: line type.
lcol: line color.
arr.col: arrow color.
arr.side: segment number on which arrowhead is drawn (1,2,3).
arr.pos: relative position of arrowhead on segment on which arrowhead is drawn.
path: outline of the 3 segments, default: left, vertical, right.
dd: length of segment arm, directed away from endpoints.
...: arguments passed to function straightarrow .

Returns

coordinates (x,y) where arrowhead is drawn

Author(s)

Karline Soetaert karline.soetaert@nioz.nl

Examples


openplotmat(main="segmentarrow")

pos <-cbind(A <- seq(0.2, 0.8, by = 0.2), rev(A))

text(pos, LETTERS[1:4], cex = 2)

segmentarrow(from = pos[1, ] + c(0, 0.05), to = pos[2, ] + c(0, 0.05),
             arr.pos = 1, arr.adj = 1, dd = 0.1, 
             path = "UHD", lcol = "darkred")

segmentarrow(from = pos[2, ] + c(-0.05, 0), to = pos[3, ] + c(-0.05, 0.01),
             arr.pos = 1, arr.adj = 1, dd = 0.1,
             lcol = "black", arr.type = "triangle")

segmentarrow(from = pos[2, ] + c(0.05, 0), to = pos[3, ] + c(0.05, 0.01),
             arr.pos = 0.5, dd = 0.3, path = "RVL", arr.side = 1,
             lcol = "lightblue", arr.type = "simple")  

segmentarrow(from = pos[3, ] + c(0.05, 0), to = pos[4, ] + c(-0.05, 0.01),
             arr.pos = 0.5, dd = 0.05, path = "RVL", lcol = "darkblue",
             arr.type = "ellipse")  

segmentarrow(from = pos[3, ] + c(0, -0.05), to = pos[4, ] + c(0, 0.05),
             arr.pos = 0.5, arr.side = 3, dd = 0.05, path = "DHU",
             lcol = "darkgreen")  

segmentarrow(from = pos[3,] + c(-0.05, -0.05), to = pos[4, ] + c(0, -0.05),
             arr.pos = 0.5, arr.side = 1:3, dd = 0.3, path = "DHU",
             lcol = "green")

Details

one segmented arrow is drawn between two points '(from, to)'

how the segments are drawn is set with path which can take on the values:

"LVR": first left then vertical then right.
"RVL": first right then vertical then left.
"UHD": first up then horizontal then down.
"DHU": first down then horizontal then up.

The segment(s) on which the arrow head is drawn is set with arr.side, which is one or more values in (1, 2, 3).

The position of the arrowhead, on the segment on which it is drawn, is set with arr.pos, a value between 0(start of segment) and 1 (end of segment)

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.

segmentarrow function