protected void drawCoil(Point a, Point b, double v1, double v2)
{
var coilLen = (float)Utils.Distance(a, b);
if (0 == coilLen)
{
return;
}
/* draw more loops for a longer coil */
Context.LineColor = NeedsHighlight ? CustomGraphics.SelectColor : CustomGraphics.GrayColor;
var loopCt = (int)Math.Ceiling(coilLen / 11);
var w = coilLen / loopCt;
var th = (float)(Utils.Angle(a, b) * 180 / Math.PI);
var pos = new Point();
for (int loop = 0; loop != loopCt; loop++)
{
Utils.InterpPoint(a, b, ref pos, (loop + 0.5) / loopCt, 0);
Context.DrawArc(pos, w, th, -180);
}
}