protected void GetArrowLinePoints(Context context, double x1, double y1, double x2, double y2,
double lineWidth, double connectorSize, double extraThickness = 0)
{
double widthX = (x2 - x1);
double lengthX = Math.Max(60, Math.Abs(widthX / 2));
double lengthY = 0;
if (widthX < 120)
{
lengthX = 60;
}
double yB = ((y1 + y2) / 2) + lengthY;
double yC = y2 + yB;
double xC = (x1 + x2) / 2;
double xA = x1 + lengthX;
double xB = x2 - lengthX;
CubicBezier bezier = new CubicBezier();
bezier.ControlPoints.Add(new PointD(x1, y1));
bezier.ControlPoints.Add(new PointD(xA, y1));
bezier.ControlPoints.Add(new PointD(xB, y2));
bezier.ControlPoints.Add(new PointD(x2 - connectorSize - extraThickness, y2));
double t = 1;
double yA = (yB * t) + (yC * (1 - t));
if (widthX <= 12)
{
bezier.ControlPoints.Insert(2, new PointD(xB, yA));
bezier.ControlPoints.Insert(2, new PointD(xC, yA));
bezier.ControlPoints.Insert(2, new PointD(xA, yA));
}
List <PointD> points = bezier.Interpolate(0.25);
PointD[] angles = new PointD[points.Count - 1];
double[] lengths = new double[points.Count - 1];
double totalLength = 0;
points.Add(points[points.Count - 1]);
for (int i = 0; i < points.Count - 2; i++)
{
PointD pt1 = points[i];
PointD pt2 = points[i + 1];
PointD pt3 = points[i + 2];
PointD delta = pt2.Substract(pt1).Addition(pt3.Substract(pt2));
double length = delta.Length();
if (length <= 1.0)
{
points.RemoveAt(i);
i--;
continue;
}
lengths[i] = length;
totalLength += length;
angles[i] = delta.Division(length);
}
double startWidth = extraThickness + 0.75;
double endWidth = extraThickness + (connectorSize / 3.5);
double currentLength = 0;
List <PointD> newPoints = new List <PointD>();
newPoints.Add(points[0]);
for (int i = 0; i < points.Count - 2; i++)
{
PointD angle = angles[i];
PointD point = points[i + 1];
double length = lengths[i];
double width = (((currentLength * (endWidth - startWidth)) / totalLength) + startWidth);
double angleX = angle.X * width;
double angleY = angle.Y * width;
double newLength = currentLength + length;
PointD pt1 = new PointD(point.X - angleY, point.Y + angleX);
PointD pt2 = new PointD(point.X + angleY, point.Y - angleX);
if (Math.Abs(newPoints[newPoints.Count - 1].X - pt1.X) > 1.0 ||
Math.Abs(newPoints[newPoints.Count - 1].Y - pt1.Y) > 1.0)
{
newPoints.Add(pt1);
}
if (Math.Abs(newPoints[0].X - pt2.X) > 1.0 ||
Math.Abs(newPoints[0].Y - pt2.Y) > 1.0)
{
newPoints.Insert(0, pt2);
}
currentLength = newLength;
}
context.LineWidth = lineWidth;
context.MoveTo(newPoints[0]);
for (int i = 1; i < newPoints.Count; ++i)
{
context.LineTo(newPoints[i]);
}
context.ClosePath();
}
