/// <summary>
/// Visits all the hot pixels which may intersect a segment (p0-p1).
/// The visitor must determine whether each hot pixel actually intersects
/// the segment.
/// </summary>
/// <param name="p0">The segment start point</param>
/// <param name="p1">The segment end point</param>
/// <param name="visitor">The visitor to apply</param>
public void Query(Coordinate p0, Coordinate p1, IKdNodeVisitor <HotPixel> visitor)
{
var queryEnv = new Envelope(p0, p1);
// expand query range to account for HotPixel extent
// expand by full width of one pixel to be safe
queryEnv.ExpandBy(1.0 / _scaleFactor);
_index.Query(queryEnv, visitor);
}
private static void QueryNode(KdNode <T> currentNode,
Envelope queryEnv, bool odd, IKdNodeVisitor <T> visitor)
{
if (currentNode == null)
{
return;
}
double min;
double max;
double discriminant;
if (odd)
{
min = queryEnv.MinX;
max = queryEnv.MaxX;
discriminant = currentNode.X;
}
else
{
min = queryEnv.MinY;
max = queryEnv.MaxY;
discriminant = currentNode.Y;
}
bool searchLeft = min < discriminant;
bool searchRight = discriminant <= max;
// search is computed via in-order traversal
if (searchLeft)
{
QueryNode(currentNode.Left, queryEnv, !odd, visitor);
}
if (queryEnv.Contains(currentNode.Coordinate))
{
visitor.Visit(currentNode);
}
if (searchRight)
{
QueryNode(currentNode.Right, queryEnv, !odd, visitor);
}
}
/// <summary>
/// Performs a range search of the points in the index.
/// </summary>
/// <param name="queryEnv">The range rectangle to query</param>
/// <param name="visitor"></param>
public void Query(Envelope queryEnv, IKdNodeVisitor <T> visitor)
{
QueryNode(_root, queryEnv, true, visitor);
}
