TITLE(arrows @@ Add Arrows to a Plot)
USAGE(
arrows(x0, y0, x1, y1, length = 0.25, angle = 30, code = 2, 
       col = par("fg"), lty = NULL, xpd = FALSE) 
segments(x0, y0, x1, y1, col = par("fg"), lty = par("lty")) 
)
ALIAS(arrows)
ALIAS(segments)
ARGUMENTS(
  ARG(x0,y0 @@ coordinates of points BOLD(from) which to draw.)
  ARG(x1,y1 @@ coordinates of points BOLD(to) which to draw.)
  ARG(length @@ length of the edges of the arrow head (in inches).)
  ARG(angle @@ angle from the shaft of the arrow to the edge of the arrow head.)
  ARG(code @@ integer code, determining ITALIC(kind) of arrows to be drawn.)
  ARG(col, lty, xpd @@ usual graphical parameters as in LANG(LINK(par)).)
)
DESCRIPTION(
LANG(segments) draws a line segment and
LANG(arrows) draws an arrow between the point LANG((x0[i], y0[i]))
and the point LANG((x1[i],y1[i])).
If LANG(code=2) an arrowhead is drawn at LANG((x0[i],y0[i])) and if
LANG(code=1) an arrowhead is drawn at LANG((x1[i],y1[i])).  If
LANG(code=3) a head is drawn at both ends of the arrow.
PARA
The graphical parameters LANG(col) and LANG(lty) can be used
to specify a color an line texture for the line segments which
make up the segments or arrows (LANG(col) may be a vector).
)
SEEALSO(
  LANG(LINK(polygon)) for slightly easier and less flexible line drawing and
  LANG(LINK(lines)) for the usual polygons.
)  
EXAMPLES(
x <- runif(12); y <- rnorm(12)
i <- order(x,y); x <- x[i]; y <- y[i]
plot(x,y, main="arrows(.) and segments(.)")
## draw arrows from point to point :
s <- seq(length(x)-1)# one shorter than data
arrows(x[s], y[s], x[s+1], y[s+1], col= 1:3)
s <- s[-length(s)]
segments(x[s], y[s], x[s+2], y[s+2], col= 'pink')
)
KEYWORD(aplot)
