/// <summary>
/// Cleans up a simple polygon by removing duplicate adjacent positions and making
/// the first position not equal the last position
/// </summary>
public static IList <T> Cleanup <T>(IEnumerable <T> positions)
{
IList <T> positionsList = CollectionAlgorithms.EnumerableToList(positions);
if (positionsList.Count < 3)
{
throw new ArgumentOutOfRangeException("positions", "At least three positions are required.");
}
List <T> cleanedPositions = new List <T>(positionsList.Count);
for (int i0 = positionsList.Count - 1, i1 = 0; i1 < positionsList.Count; i0 = i1++)
{
T v0 = positionsList[i0];
T v1 = positionsList[i1];
if (!v0.Equals(v1))
{
cleanedPositions.Add(v1);
}
}
cleanedPositions.TrimExcess();
return(cleanedPositions);
}
public void EnumerableToList2()
{
Dictionary <int, int> dictionary = new Dictionary <int, int>();
dictionary.Add(0, 0);
dictionary.Add(1, 1);
IList <KeyValuePair <int, int> > returnedList = CollectionAlgorithms.EnumerableToList(dictionary);
Assert.AreEqual(2, returnedList.Count);
Assert.AreEqual(new KeyValuePair <int, int>(0, 0), returnedList[0]);
Assert.AreEqual(new KeyValuePair <int, int>(1, 1), returnedList[1]);
}
public void EnumerableToList()
{
IList <int> list = new List <int>();
list.Add(0);
list.Add(1);
IList <int> returnedList = CollectionAlgorithms.EnumerableToList(list);
Assert.AreEqual(2, returnedList.Count);
Assert.AreEqual(0, returnedList[0]);
Assert.AreEqual(1, returnedList[1]);
}
public static double ComputeArea(IEnumerable <Vector2D> positions)
{
IList <Vector2D> positionsList = CollectionAlgorithms.EnumerableToList(positions);
if (positionsList.Count < 3)
{
throw new ArgumentOutOfRangeException("positions", "At least three positions are required.");
}
double area = 0.0;
//
// Compute the area of the polygon. The sign of the area determines the winding order.
//
for (int i0 = positionsList.Count - 1, i1 = 0; i1 < positionsList.Count; i0 = i1++)
{
Vector2D v0 = positionsList[i0];
Vector2D v1 = positionsList[i1];
area += (v0.X * v1.Y) - (v1.X * v0.Y);
}
return(area * 0.5);
}
public void EnumerableToListNull()
{
CollectionAlgorithms.EnumerableToList <int>(null);
}