private void DrawArrow(Graphics gr, Pen pen, PointF p1, PointF p2, EndpointStyle style1, EndpointStyle style2)
{
// Draw the shaft.
gr.DrawLine(pen, p1, p2);
// Find the arrow shaft unit vector.
float vx = p2.X - p1.X;
float vy = p2.Y - p1.Y;
float dist = (float)Math.Sqrt(vx * vx + vy * vy);
vx /= dist;
vy /= dist;
float length = dist / 4;
if (dist < 4) // do not try to paint arrow with length < 1
{
if (dist >= 1) // paint nothing if line is < 1
{
gr.DrawLine(pen, p1, p2);
}
return;
}
// Draw the start.
if (style1 == EndpointStyle.ArrowHead)
{
DrawArrowhead(gr, pen, p1, -vx, -vy, length);
}
else if (style1 == EndpointStyle.Fletching)
{
DrawArrowhead(gr, pen, p1, vx, vy, length);
}
// Draw the end.
if (style2 == EndpointStyle.ArrowHead)
{
DrawArrowhead(gr, pen, p2, vx, vy, length);
}
else if (style2 == EndpointStyle.Fletching)
{
DrawArrowhead(gr, pen, p2, -vx, -vy, length);
}
}
// Draw arrow heads or tails for the
// segment from p1 to p2.
private static void DrawArrow(DrawingContext gr, Pen pen, Point p1, Point p2, double length, EndpointStyle style1, EndpointStyle style2)
{
// Draw the shaft.
gr.DrawLine(pen, p1, p2);
// Find the arrow shaft unit vector.
double vx = p2.X - p1.X;
double vy = p2.Y - p1.Y;
float dist = (float)Math.Sqrt(vx * vx + vy * vy);
vx /= dist;
vy /= dist;
// Draw the start.
if (style1 == EndpointStyle.ArrowHead)
{
DrawArrowhead(gr, pen, p1, -vx, -vy, length);
}
else if (style1 == EndpointStyle.Fletching)
{
DrawArrowhead(gr, pen, p1, vx, vy, length);
}
// Draw the end.
if (style2 == EndpointStyle.ArrowHead)
{
DrawArrowhead(gr, pen, p2, vx, vy, length);
}
else if (style2 == EndpointStyle.Fletching)
{
DrawArrowhead(gr, pen, p2, -vx, -vy, length);
}
}
