// Initialize the quadtree.
private void Form1_Load(object sender, EventArgs e)
{
Root = new QuadtreeNode(new RectangleF(0, 0,
pointsPictureBox.ClientSize.Width - 1,
pointsPictureBox.ClientSize.Height - 1));
}
// Add a point to this subtree.
public void AddPoint(PointF newPoint)
{
// See if this quadtree node us full.
if ((Points != null) && (Points.Count + 1 > MaxPoints))
{
// Divide this quadtree node.
float wid = (Area.Right - Area.Left) / 2f;
float hgt = (Area.Bottom - Area.Top) / 2f;
NWchild = new QuadtreeNode(new RectangleF(Area.Left, Area.Top, wid, hgt));
NEchild = new QuadtreeNode(new RectangleF(Area.Left + wid, Area.Top, wid, hgt));
SEchild = new QuadtreeNode(new RectangleF(Area.Left + wid, Area.Top + hgt, wid, hgt));
SWchild = new QuadtreeNode(new RectangleF(Area.Left, Area.Top + hgt, wid, hgt));
// Move the points into the appropriate subtrees.
foreach (PointF pt in Points)
{
if (pt.Y < Ymid)
{
if (pt.X < Xmid)
{
NWchild.AddPoint(pt);
}
else
{
NEchild.AddPoint(pt);
}
}
else
{
if (pt.X < Xmid)
{
SWchild.AddPoint(pt);
}
else
{
SEchild.AddPoint(pt);
}
}
}
// Remove this node's Points list.
Points = null;
}
// Add the point to the appropriate subtree.
if (Points != null)
{
Points.Add(newPoint);
}
else if (newPoint.Y < Ymid)
{
if (newPoint.X < Xmid)
{
NWchild.AddPoint(newPoint);
}
else
{
NEchild.AddPoint(newPoint);
}
}
else
{
if (newPoint.X < Xmid)
{
SWchild.AddPoint(newPoint);
}
else
{
SEchild.AddPoint(newPoint);
}
}
}
