Double-Lined ArrowHead

[discoleo]

The Double-Lined Arrowhead can now be easily composed using 2 helper functions:

• a high level helper function: arrH2;
• the simple arrHS helper function;

  # Double Lined ArrowHead: --->>
  # - a high-level helper function;
  arrH2 = function(x, y, slope, d=-1, dV=c(d, -d)) {
  # Shift point along line:
  arrHead = list(arrHS(x, y, slope=slope, d = dV));
  # Double Arrow
  p2 = shiftPoint(c(x, y), slope=slope, d = - d);
  arrHead2 = list(arrHS(p2[1], p2[2], slope=slope, d = dV));
  arrHead  = c(arrHead, arrHead2);
  return(arrHead);
  }
  # Double Lined Head
  arrowDH = function(x, y, d=0.2, lwd=1, d.head=-1, h.lwd=lwd, col="red", asD=FALSE) {
  slope = compute_slope(x, y);
  xylist = function(x, y) list(list(x=x, y=y));
  ### ArrowTail
  if(asD) {
      arrow = shiftLine(x, y, d = c(d, -d), slope=slope);
      arrow = list(arrow, lwd=lwd);
  } else {
      arrow = xylist(x, y);
      arrow = c(arrow, lwd = lwd);
  }
  ### Head
  arrHead = arrH2(x[2], y[2], slope=slope, d=d, dV=d.head);
  arrHead$lwd = h.lwd;
  ### Full Arrow
  lst = list(Arrow=arrow, Head=arrHead);
  class(lst) = c("arrow", "list");
  # Plot lines:
  print("Finished")
  lines(lst, col=col);
  invisible(lst);
  }

[DarianFlorianVoda]

Particularly solved for the following input:

plot.base()
x = c(0, 6); y = c(1, 6);
arrowDH(x, y, d=-0.2, lwd=2);

[DarianFlorianVoda]

Plot view: