Class Area

Represents an arbitrarily-shaped 2D area. Stores and provides access to a list of each unique position in the area.

Inheritance

object

Area

Implements

IReadOnlyArea

IMatchable<IReadOnlyArea>

IEnumerable<Point>

IEnumerable

Inherited Members

object.GetType()

object.MemberwiseClone()

object.Equals(object)

object.Equals(object, object)

object.ReferenceEquals(object, object)

object.GetHashCode()

Namespace: SadRogue.Primitives

Assembly: TheSadRogue.Primitives.dll

Syntax

public class Area : IReadOnlyArea, IMatchable<IReadOnlyArea>, IEnumerable<Point>, IEnumerable

Constructors

Area(IEnumerable<Point>, IEqualityComparer<Point>?)

Constructor that takes initial points to add to the area.

Declaration

public Area(IEnumerable<Point> initialPoints, IEqualityComparer<Point>? pointHasher = null)

Parameters

Type	Name	Description
IEnumerable<Point>	initialPoints	Initial points to add to the area.
IEqualityComparer<Point>	pointHasher	A custom equality comparer/hashing algorithm to use when storing points. If not specified, it defaults to using the Equals and GetHashCode functions of the Point struct.

Area(IEqualityComparer<Point>?)

Constructor.

Declaration

public Area(IEqualityComparer<Point>? pointHasher = null)

Parameters

Type	Name	Description
IEqualityComparer<Point>	pointHasher	A custom equality comparer/hashing algorithm to use when storing points. If not specified, it defaults to using the Equals and GetHashCode functions of the Point struct.

Area(IEqualityComparer<Point>?, params Point[])

Constructor that takes initial points to add to the area.

Declaration

public Area(IEqualityComparer<Point>? pointHasher = null, params Point[] initialPoints)

Parameters

Type	Name	Description
IEqualityComparer<Point>	pointHasher	A custom equality comparer/hashing algorithm to use when storing points. If not specified, it defaults to using the Equals and GetHashCode functions of the Point struct.
Point[]	initialPoints	Initial points to add to the area.

Fields

PointHasher

Hashing algorithm being used to store points added to this area.

Declaration

public readonly IEqualityComparer<Point> PointHasher

Field Value

Type	Description
IEqualityComparer<Point>

Properties

Bounds

Smallest possible rectangle that encompasses every position in the area.

Declaration

public Rectangle Bounds { get; }

Property Value

Type	Description
Rectangle

Count

Number of (unique) positions in the area.

Declaration

public int Count { get; }

Property Value

Type	Description
int

this[int]

Returns positions from the area in the same fashion you would via a list.

Declaration

public Point this[int index] { get; }

Parameters

Type	Name	Description
int	index	Index of list to retrieve.

Property Value

Type	Description
Point

UseIndexEnumeration

Whether or not it is more efficient for this implementation to use enumeration by index, rather than generic IEnumerable, when iterating over positions using ReadOnlyAreaPositionsEnumerator.

Declaration

public bool UseIndexEnumeration { get; }

Property Value

Type	Description
bool

Remarks

Set this to true if your indexer implementation scales well (constant time), and is relatively fast. Implementations with more complex indexers should set this to false.

The default interface implementation returns false, in order to preserve backwards compatibility with previous versions.

If you set this to false, your IEnumerable.GetEnumerator() implementations must NOT call return a ReadOnlyAreaPositionsEnumerator, as this will create an infinite loop.

Methods

Add(IReadOnlyArea)

Adds all positions in the given map area to this one.

Declaration

public void Add(IReadOnlyArea area)

Parameters

Type	Name	Description
IReadOnlyArea	area	Area containing positions to add.

Add(Point)

Adds the given position to the list of points within the area if it is not already in the list, or does nothing otherwise.

Declaration

public void Add(Point position)

Parameters

Type	Name	Description
Point	position	The position to add.

Remarks

Because the class uses a hash set internally to determine what points have already been added, this is an average case O(1) operation.

Add(Rectangle)

Adds all positions in the given rectangle to the area, if they are not already present.

Declaration

public void Add(Rectangle rectangle)

Parameters

Type	Name	Description
Rectangle	rectangle	Rectangle indicating which points to add.

Add(IEnumerable<Point>)

Adds the given positions to the list of points within the area if they are not already in the list.

Declaration

public void Add(IEnumerable<Point> positions)

Parameters

Type	Name	Description
IEnumerable<Point>	positions	Positions to add to the list.

Add(int, int)

Adds the given position to the list of points within the area if it is not already in the list, or does nothing otherwise.

Declaration

public void Add(int positionX, int positionY)

Parameters

Type	Name	Description
int	positionX	X-value of the position to add.
int	positionY	Y-value of the position to add.

Remarks

Because the class uses a hash set internally to determine what points have already been added, this is an average case O(1) operation.

Contains(IReadOnlyArea)

Returns whether or not the given area is completely contained within the current one.

Declaration

public bool Contains(IReadOnlyArea area)

Parameters

Type	Name	Description
IReadOnlyArea	area	Area to check.

Returns

Type	Description
bool	True if the given area is completely contained within the current one, false otherwise.

Contains(Point)

Determines whether or not the given position is within the area or not.

Declaration

public bool Contains(Point position)

Parameters

Type	Name	Description
Point	position	The position to check.

Returns

Type	Description
bool	True if the specified position is within the area, false otherwise.

Contains(int, int)

Determines whether or not the given position is within the area or not.

Declaration

public bool Contains(int positionX, int positionY)

Parameters

Type	Name	Description
int	positionX	X-value of the position to check.
int	positionY	Y-value of the position to check.

Returns

Type	Description
bool	True if the specified position is within the area, false otherwise.

GetDifference(IReadOnlyArea, IReadOnlyArea, IEqualityComparer<Point>?)

Gets an area containing all positions in area1, minus those that are in area2.

Declaration

public static Area GetDifference(IReadOnlyArea area1, IReadOnlyArea area2, IEqualityComparer<Point>? pointHasher = null)

Parameters

Type	Name	Description
IReadOnlyArea	area1
IReadOnlyArea	area2
IEqualityComparer<Point>	pointHasher	A custom equality comparer/hashing algorithm to use when storing points in the new Area. If not specified, it defaults to using the Equals and GetHashCode functions of the Point struct.

Returns

Type	Description
Area	A area with exactly those positions in area1 that are NOT in area2.

GetEnumerator()

Returns an enumerator that iterates through all positions in the Area, in the order they were added.

Declaration

public List<Point>.Enumerator GetEnumerator()

Returns

Type	Description
List<Point>.Enumerator	An enumerator that iterates through all the positions in the Area, in the order they were added.

GetIntersection(IReadOnlyArea, IReadOnlyArea, IEqualityComparer<Point>?)

Gets an area containing exactly those positions contained in both of the given areas.

Declaration

public static Area GetIntersection(IReadOnlyArea area1, IReadOnlyArea area2, IEqualityComparer<Point>? pointHasher = null)

Parameters

Type	Name	Description
IReadOnlyArea	area1
IReadOnlyArea	area2
IEqualityComparer<Point>	pointHasher	A custom equality comparer/hashing algorithm to use when storing points in the new Area. If not specified, it defaults to using the Equals and GetHashCode functions of the Point struct.

Returns

Type	Description
Area	An area containing exactly those positions contained in both of the given areas.

GetUnion(IReadOnlyArea, IReadOnlyArea, IEqualityComparer<Point>?)

Gets an area containing every position in one or both given areas.

Declaration

public static Area GetUnion(IReadOnlyArea area1, IReadOnlyArea area2, IEqualityComparer<Point>? pointHasher = null)

Parameters

Type	Name	Description
IReadOnlyArea	area1
IReadOnlyArea	area2
IEqualityComparer<Point>	pointHasher	A custom equality comparer/hashing algorithm to use when storing points in the new Area. If not specified, it defaults to using the Equals and GetHashCode functions of the Point struct.

Returns

Type	Description
Area	An area containing only those positions in one or both of the given areas.

Intersects(IReadOnlyArea)

Returns whether or not the given map area intersects the current one. If you intend to determine/use the exact intersection based on this return value, it is best to instead call the GetIntersection(IReadOnlyArea, IReadOnlyArea, IEqualityComparer<Point>?), and check the number of positions in the result (0 if no intersection).

Declaration

public bool Intersects(IReadOnlyArea area)

Parameters

Type	Name	Description
IReadOnlyArea	area	The area to check.

Returns

Type	Description
bool	True if the given map area intersects the current one, false otherwise.

Matches(IReadOnlyArea?)

Compares for equality. Returns true if the two areas contain exactly the same points.

Declaration

public bool Matches(IReadOnlyArea? other)

Parameters

Type	Name	Description
IReadOnlyArea	other

Returns

Type	Description
bool	True if the areas contain exactly the same points, false otherwise.

Remove(IReadOnlyArea)

Removes all positions in the given map area from this one.

Declaration

public void Remove(IReadOnlyArea area)

Parameters

Type	Name	Description
IReadOnlyArea	area	Area containing positions to remove.

Remove(Point)

Removes the given position specified from the area. Particularly when the remove operation operation changes the bounds, this operation can be expensive, so if you must do multiple remove operations, it would be best to group them into 1 using Remove(IEnumerable<Point>).

Declaration

public void Remove(Point position)

Parameters

Type	Name	Description
Point	position	The position to remove.

Remove(Rectangle)

Removes all positions in the given rectangle from this area.

Declaration

public void Remove(Rectangle rectangle)

Parameters

Type	Name	Description
Rectangle	rectangle	Rectangle containing positions to remove.

Remove(HashSet<Point>)

Removes the given positions from the specified area.

Declaration

public void Remove(HashSet<Point> positions)

Parameters

Type	Name	Description
HashSet<Point>	positions	Positions to remove.

Remove(IEnumerable<Point>)

Removes the given positions from the specified area.

Declaration

public void Remove(IEnumerable<Point> positions)

Parameters

Type	Name	Description
IEnumerable<Point>	positions	Positions to remove.

Remove(Func<Point, bool>)

Removes positions for which the given predicate returns true from the area.

Declaration

public void Remove(Func<Point, bool> predicate)

Parameters

Type	Name	Description
Func<Point, bool>	predicate	Predicate returning true for positions that should be removed.

Remove(int, int)

Removes the given position specified from the area. Particularly when the remove operation operation changes the bounds, this operation can be expensive, so if you must do multiple remove operations, it would be best to group them into 1 using Remove(IEnumerable<Point>).

Declaration

public void Remove(int positionX, int positionY)

Parameters

Type	Name	Description
int	positionX	X-value of the position to remove.
int	positionY	Y-value of the position to remove.

ToString()

Returns the string of each position in the area, in a square-bracket enclosed list, eg. [(1, 2), (3, 4), (5, 6)].

Declaration

public override string ToString()

Returns

Type	Description
string	A string representation of those coordinates in the area.

Overrides

object.ToString()

Operators

operator +(Area, Point)

Creates an area with the positions all shifted by the given vector.

Declaration

public static Area operator +(Area lhs, Point rhs)

Parameters

Type	Name	Description
Area	lhs
Point	rhs	Vector to add to each position in lhs.

Returns

Type	Description
Area	An area with the positions all translated by the given amount in x and y directions.

Implements

IReadOnlyArea

IMatchable<T>

IEnumerable<T>

IEnumerable

Extension Methods

PropertyChangedEventHelpers.SafelySetProperty<TObject, TProperty>(TObject, ref TProperty, TProperty, EventHandler<ValueChangedEventArgs<TProperty>>?)

PropertyChangedEventHelpers.SafelySetProperty<TObject, TProperty>(TObject, ref TProperty, TProperty, EventHandler<ValueChangedEventArgs<TProperty>>?, EventHandler<ValueChangedEventArgs<TProperty>>?)

ReadOnlyAreaExtensions.FastEnumerator(IReadOnlyArea)

ReadOnlyAreaExtensions.PerimeterPositions(IReadOnlyArea, AdjacencyRule)

ToStringExtensions.ExtendToString<T>(IEnumerable<T>, string, Func<T, string>?, string, string)