/// <summary>
/// Finds all intersections between the specified line segments, using a brute force
/// algorithm and given the specified epsilon for coordinate comparisons.</summary>
/// <param name="lines">
/// An <see cref="Array"/> containing the <see cref="LineD"/> instances to intersect.
/// </param>
/// <param name="epsilon">
/// The maximum absolute difference at which two coordinates should be considered equal.
/// </param>
/// <returns>
/// A lexicographically sorted <see cref="Array"/> containing a <see cref="MultiLinePoint"/>
/// for every point of intersection between the <paramref name="lines"/>.</returns>
/// <exception cref="ArgumentNullException">
/// <paramref name="lines"/> is a null reference.</exception>
/// <exception cref="ArgumentOutOfRangeException">
/// <paramref name="epsilon"/> is equal to or less than zero.</exception>
/// <remarks>
/// <b>FindSimple</b> is identical with the basic <see cref="FindSimple(LineD[])"/> overload
/// but uses the specified <paramref name="epsilon"/> to determine intersections between the
/// specified <paramref name="lines"/> and to combine nearby intersections.</remarks>
public static MultiLinePoint[] FindSimple(LineD[] lines, double epsilon)
{
if (lines == null)
{
ThrowHelper.ThrowArgumentNullException("lines");
}
if (epsilon <= 0.0)
{
ThrowHelper.ThrowArgumentOutOfRangeException(
"epsilon", epsilon, Strings.ArgumentNotPositive);
}
var crossings = new BraidedTree <PointD, EventPoint>(
(a, b) => PointDComparerY.CompareEpsilon(a, b, epsilon));
for (int i = 0; i < lines.Length - 1; i++)
{
for (int j = i + 1; j < lines.Length; j++)
{
var crossing = lines[i].Intersect(lines[j], epsilon);
if (crossing.Exists)
{
PointD p = crossing.Shared.Value;
BraidedTreeNode <PointD, EventPoint> node;
crossings.TryAddNode(p, new EventPoint(p), out node);
node._value.TryAddLines(i, crossing.First, j, crossing.Second);
}
}
}
return(EventPoint.Convert(crossings.Values));
}
/// <overloads>
/// Finds all intersections between the specified line segments, using a brute force
/// algorithm.</overloads>
/// <summary>
/// Finds all intersections between the specified line segments, using a brute force
/// algorithm and exact coordinate comparisons.</summary>
/// <param name="lines">
/// An <see cref="Array"/> containing the <see cref="LineD"/> instances to intersect.
/// </param>
/// <returns>
/// A lexicographically sorted <see cref="Array"/> containing a <see cref="MultiLinePoint"/>
/// for every point of intersection between the <paramref name="lines"/>.</returns>
/// <exception cref="ArgumentNullException">
/// <paramref name="lines"/> is a null reference.</exception>
/// <remarks><para>
/// <b>FindSimple</b> performs a pairwise intersection of every <paramref name="lines"/>
/// element with every other element. The runtime is therefore always O(n^2), regardless of
/// the number of intersections found.
/// </para><para>
/// However, the constant factor is low and O(n^2) intersections are found in optimal time
/// because <b>FindSimple</b> performs no additional work to avoid testing for possible
/// intersections. For a small number of <paramref name="lines"/> (n < 50),
/// <b>FindSimple</b> usually beats the sweep line algorithm implemented by <see
/// cref="Find"/> regardless of the number of intersections.</para></remarks>
public static MultiLinePoint[] FindSimple(LineD[] lines)
{
if (lines == null)
{
ThrowHelper.ThrowArgumentNullException("lines");
}
var crossings = new BraidedTree <PointD, EventPoint>(PointDComparerY.CompareExact);
for (int i = 0; i < lines.Length - 1; i++)
{
for (int j = i + 1; j < lines.Length; j++)
{
var crossing = lines[i].Intersect(lines[j]);
if (crossing.Exists)
{
PointD p = crossing.Shared.Value;
BraidedTreeNode <PointD, EventPoint> node;
crossings.TryAddNode(p, new EventPoint(p), out node);
node._value.TryAddLines(i, crossing.First, j, crossing.Second);
}
}
}
return(EventPoint.Convert(crossings.Values));
}
/// <overloads>
/// Initializes a new instance of the <see cref="BraidedTreeNode{TKey, TValue}"/> class.
/// </overloads>
/// <summary>
/// Initializes a new instance of the <see cref="BraidedTreeNode{TKey, TValue}"/> class with
/// the specified tree structure.</summary>
/// <param name="tree">
/// The <see cref="BraidedTree{TKey, TValue}"/> that contains the <see
/// cref="BraidedTreeNode{TKey, TValue}"/>.</param>
/// <exception cref="ArgumentNullException">
/// <paramref name="tree"/> is a null reference.</exception>
/// <remarks>
/// <see cref="Priority"/> is set to -1.0. The <see cref="Key"/> property remains at its
/// default value, which is a null reference if <typeparamref name="TKey"/> is a reference
/// type. Use this constructor only for the <see cref="BraidedTree{TKey, TValue}.RootNode"/>
/// of the specified <paramref name="tree"/>.</remarks>
internal BraidedTreeNode(BraidedTree <TKey, TValue> tree)
{
if (tree == null)
{
ThrowHelper.ThrowArgumentNullException("tree");
}
_tree = tree;
_next = _previous = this;
_priority = -1.0;
}
/// <summary>
/// Removes the <see cref="BraidedTreeNode{TKey, TValue}"/>, which must be a leaf node, from
/// the tree structure.</summary>
/// <remarks><para>
/// <b>RemoveTree</b> sets the <see cref="Left"/> or <see cref="Right"/> reference of the
/// <see cref="Parent"/> node, whichever matches the current instance, to a null reference,
/// and updates the chains of <see cref="Previous"/> and <see cref="Next"/> references to
/// exclude the current instance.
/// </para><para>
/// All <see cref="BraidedTreeNode{TKey, TValue}"/> references of the current instance are
/// reset to default values, as with <see cref="Clear"/>. Moreover, <b>RemoveTree</b> sets
/// the <see cref="Tree"/> property to a null reference.</para></remarks>
internal void RemoveTree()
{
Debug.Assert(_left == null && _right == null);
if (_parent._left == this)
{
_parent._left = null;
}
else
{
Debug.Assert(_parent._right == this);
_parent._right = null;
}
_parent = null;
RemoveList();
_tree = null;
}
/// <summary>
/// Initializes a new instance of the <see cref="BraidedTreeNode{TKey, TValue}"/> class with
/// the specified tree structure, key and value.</summary>
/// <param name="tree">
/// The <see cref="BraidedTree{TKey, TValue}"/> that contains the <see
/// cref="BraidedTreeNode{TKey, TValue}"/>.</param>
/// <param name="key">
/// The key of the <see cref="BraidedTreeNode{TKey, TValue}"/>.</param>
/// <param name="value">
/// The value of the <see cref="BraidedTreeNode{TKey, TValue}"/>.</param>
/// <exception cref="ArgumentNullException">
/// <paramref name="tree"/> or <paramref name="key"/> is a null reference.</exception>
/// <exception cref="KeyMismatchException">
/// <paramref name="value"/> is an <see cref="IKeyedValue{TKey}"/> instance whose <see
/// cref="KeyValuePair{TKey, TValue}.Key"/> differs from the specified <paramref
/// name="key"/>.</exception>
/// <remarks>
/// <see cref="Priority"/> is set to a random value in the open interval [0, 1).</remarks>
internal BraidedTreeNode(BraidedTree <TKey, TValue> tree, TKey key, TValue value)
{
if (tree == null)
{
ThrowHelper.ThrowArgumentNullException("tree");
}
if (value is IKeyedValue <TKey> )
{
CollectionsUtility.ValidateKey(Key, value);
}
else if (key == null)
{
ThrowHelper.ThrowArgumentNullException("key");
}
_tree = tree;
_next = _previous = this;
_priority = tree.Random.NextDouble();
Key = key; _value = value;
}
public void WalkTree()
{
const int radius = 3000;
var array = new KeyValuePair <PointD, CloneableType> [2 * radius];
for (int i = 0; i < array.Length; i++)
{
array[i] = new KeyValuePair <PointD, CloneableType>(
new PointD(i - radius, radius - i),
new CloneableType(String.Format("bar{0:D3} value", i)));
}
var tree = new QuadTree <CloneableType>(
new RectD(-2 * radius, -2 * radius, 4 * radius, 4 * radius));
Assert.AreEqual(tree, tree.RootNode.Tree);
Assert.AreEqual(1, tree.Nodes.Count);
// test adding elements
foreach (var pair in array)
{
tree.Add(pair.Key, pair.Value);
}
Assert.AreEqual(array.Length, tree.Count);
Assert.AreEqual(145, tree.Nodes.Count);
// test moving elements without hint node
PointD offset = new PointD(0.1, 0.1);
foreach (var pair in array)
{
tree.Move(pair.Key, pair.Key + offset);
}
// test moving elements with hint node
QuadTreeNode <CloneableType> node = null;
foreach (var pair in array)
{
node = tree.Move(pair.Key + offset, pair.Key, node);
}
Assert.AreEqual(array.Length, tree.Count);
Assert.AreEqual(145, tree.Nodes.Count);
// test finding elements
foreach (var pair in array)
{
CloneableType value;
Assert.IsTrue(tree.TryGetValue(pair.Key, out value));
Assert.AreEqual(pair.Value, value);
node = tree.FindNode(pair.Key);
Assert.AreEqual(tree, node.Tree);
Assert.IsTrue(node.Data.Contains(pair));
var valueNode = tree.FindNodeByValue(pair.Value);
Assert.AreEqual(node, valueNode);
}
// test finding elements in range
var range = new RectD(-radius, 0, 2 * radius, 2 * radius);
var elements = tree.FindRange(range);
Assert.AreEqual(radius + 1, elements.Count);
for (int i = 0; i <= radius; i++)
{
CloneableType value;
Assert.IsTrue(elements.TryGetValue(array[i].Key, out value));
Assert.AreEqual(array[i].Value, value);
}
// compare range search to BraidedTree
var braidedTree = new BraidedTree <PointD, CloneableType>(PointDComparerY.CompareExact);
foreach (var pair in array)
{
braidedTree.Add(pair);
}
// BraidedTree sorts by y-coordinates, so we must restrict x-coordinates
var braidedElements = braidedTree.FindRange(range.TopLeft, range.BottomRight,
n => (n.Key.X >= range.Left && n.Key.X <= range.Right));
Assert.AreEqual(elements.Count, braidedElements.Count);
foreach (var pair in elements)
{
CloneableType value;
Assert.IsTrue(braidedElements.TryGetValue(pair.Key, out value));
Assert.AreEqual(pair.Value, value);
}
// test element enumeration
foreach (var pair in tree)
{
CloneableType value;
Assert.IsTrue(braidedTree.TryGetValue(pair.Key, out value));
Assert.AreEqual(value, pair.Value);
braidedTree.Remove(pair.Key);
}
Assert.AreEqual(0, braidedTree.Count);
// test removing elements
foreach (var pair in array)
{
Assert.IsTrue(tree.Remove(pair.Key));
}
Assert.AreEqual(0, tree.Count);
Assert.AreEqual(1, tree.Nodes.Count);
}
/// <summary>
/// Initializes a new instance of the <see cref="Status"/> class.</summary>
internal Status()
{
Crossings = new List <EventPoint>();
Schedule = new BraidedTree <PointD, EventPoint>(PointDComparerY.CompareExact);
SweepLine = new BraidedTree <Int32, Int32>(CompareLines);
}