private static IEnumerable <Index2D> Spiral(Index2D lowerBounds, Index2D upperBounds)
{
Contracts.Requires.That(lowerBounds.X <= upperBounds.X);
Contracts.Requires.That(lowerBounds.Y <= upperBounds.Y);
Contracts.Requires.That(MiddleIndex.Get(lowerBounds, upperBounds, RoundUp) == Index2D.Zero);
return(new Spiral2D(new Spiral2D.Options()
{
Spirals = Math.Max(
Math.Max(Math.Abs(lowerBounds.X), Math.Abs(lowerBounds.Y)),
Math.Max(Math.Abs(upperBounds.X), Math.Abs(upperBounds.Y))),
}));
}
private static IEnumerable <Index3D> SpiralColumns(Index3D lowerBounds, Index3D upperBounds)
{
Contracts.Requires.That(lowerBounds.X <= upperBounds.X);
Contracts.Requires.That(lowerBounds.Y <= upperBounds.Y);
Contracts.Requires.That(lowerBounds.Z <= upperBounds.Z);
Contracts.Requires.That(MiddleIndex.Get(lowerBounds, upperBounds, RoundUp) == Index3D.Zero);
foreach (var index in Spiral(lowerBounds.ProjectDownYAxis(), upperBounds.ProjectDownYAxis()))
{
yield return(new Index3D(index.X, 0, index.Y));
int yUp = 1;
int yDown = -1;
bool continueLoop = true;
while (continueLoop)
{
continueLoop = false;
if (yUp <= upperBounds.Y)
{
yield return(new Index3D(index.X, yUp, index.Y));
yUp++;
continueLoop = true;
}
if (yDown >= lowerBounds.Y)
{
yield return(new Index3D(index.X, yDown, index.Y));
yDown--;
continueLoop = true;
}
}
}
}
public static Index2D GetMiddleIndex(this IIndexingBounds <Index2D> bounds, bool roundUp = false)
{
Contracts.Requires.That(bounds != null);
return(MiddleIndex.Get(bounds.LowerBounds, bounds.UpperBounds, roundUp));
}
public static Index1D GetMiddleIndex <T>(this T[] array, bool roundUp = false)
{
Contracts.Requires.That(array != null);
return(MiddleIndex.Get(array.GetLowerBounds(), array.GetUpperBounds(), roundUp));
}