Package com.google.common.geometry

Class S2ShapeIndex.S2ClippedShape

java.lang.Object

com.google.common.geometry.S2ShapeIndex.Cell

com.google.common.geometry.S2ShapeIndex.S2ClippedShape

All Implemented Interfaces:

S2Iterator.Entry, java.io.Serializable

Direct Known Subclasses:

S2ShapeIndex.S2ClippedShape.Contained, S2ShapeIndex.S2ClippedShape.EdgeRange, S2ShapeIndex.S2ClippedShape.ManyEdges, S2ShapeIndex.S2ClippedShape.OneEdge

Enclosing class:

S2ShapeIndex

public abstract static class S2ShapeIndex.S2ClippedShape
extends S2ShapeIndex.Cell

S2ClippedShape represents the part of a shape that intersects an S2Cell. It consists of the set of edge ids that intersect that cell, and a boolean indicating whether the center of the cell is inside the shape (for shapes that have an interior). Edges themselves are not clipped; we always use the original edges for intersection tests so that the results will be the same as the original shape.

Most of the index memory is consumed here, so we have several strategies to be as efficient as possible:

• Since only the first clipped shape in a cell needs to store the cell ID, we have subclasses for both cases based on whether a cell ID was provided.
• Since no edges, one edge, and one dense range of edges are very common cases, we have more efficient subclasses for those situations, in addition to the general purpose implementation.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static class	S2ShapeIndex.S2ClippedShape.Contained	An S2ClippedShape for a shape that completely contains the cell (no edge intersections and containsCenter is true.)
private static class	S2ShapeIndex.S2ClippedShape.EdgeRange	An S2ClippedShape containing a single range of contiguous edge IDs.
private static class	S2ShapeIndex.S2ClippedShape.ManyEdges	An S2ClippedShape that contains the non-contiguous edges from start to end in edges.
private static class	S2ShapeIndex.S2ClippedShape.OneEdge	An S2ClippedShape that contains a single edge from a given shape.

Field Summary

Fields

Modifier and Type	Field	Description
private S2Shape	shape	If positive, this is the shape ID and the shape does not contain the center of the cell.

Constructor Summary

Constructors

Modifier	Constructor	Description
private	S2ClippedShape(S2Shape shape)

Method Summary

Modifier and Type	Method	Description
S2ShapeIndex.S2ClippedShape	clipped(int i)	For implementing the Cell interface, this class contains just 1 shape (itself.)
abstract boolean	containsCenter()	Returns whether the center of the S2CellId is inside the shape, and always returns false for shapes that do not have an interior according to S2Shape.hasInterior().
boolean	containsEdge(int edgeId)	Returns whether the clipped shape contains the given edge id.
(package private) static S2ShapeIndex.S2ClippedShape	create(S2CellId cellId, S2Shape shape, boolean containsCenter, int[] edges)
(package private) static S2ShapeIndex.S2ClippedShape	create(S2CellId cellId, S2Shape shape, boolean containsCenter, int offset, int count)
(package private) static S2ShapeIndex.S2ClippedShape	create(S2CellId cellId, S2Shape shape, boolean containsCenter, java.util.List<S2ShapeIndex.ClippedEdge> edges, int start, int end)
abstract int	edge(int i)	Returns the ith edge ID of this clipped shape.
abstract int	numEdges()	Returns the number of edges that intersect the S2CellId.
int	numShapes()	For implementing the Cell interface, this class contains just 1 shape (itself.)
S2Shape	shape()	Returns the original shape this clipped shape was clipped from.

Methods inherited from class com.google.common.geometry.S2ShapeIndex.Cell

create, findClipped, id

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

shape

private final S2Shape shape

If positive, this is the shape ID and the shape does not contain the center of the cell. Otherwise the shape ID is ~this.shapeId and the shape does contains the center of the cell. This is done to save memory, since this single bit of information can otherwise be padded out up to 4 or 8 additional bytes, depending on the fields in the subclass.

Constructor Detail

S2ClippedShape

private S2ClippedShape(S2Shape shape)

Method Detail

create

static S2ShapeIndex.S2ClippedShape create(S2CellId cellId,
                                          S2Shape shape,
                                          boolean containsCenter,
                                          java.util.List<S2ShapeIndex.ClippedEdge> edges,
                                          int start,
                                          int end)

create

static S2ShapeIndex.S2ClippedShape create(@Nullable
                                          S2CellId cellId,
                                          S2Shape shape,
                                          boolean containsCenter,
                                          int[] edges)

create

static S2ShapeIndex.S2ClippedShape create(@Nullable
                                          S2CellId cellId,
                                          S2Shape shape,
                                          boolean containsCenter,
                                          int offset,
                                          int count)

shape

public final S2Shape shape()

Returns the original shape this clipped shape was clipped from.

containsCenter

public abstract boolean containsCenter()

Returns whether the center of the S2CellId is inside the shape, and always returns false for shapes that do not have an interior according to S2Shape.hasInterior().

numEdges

public abstract int numEdges()

Returns the number of edges that intersect the S2CellId.

edge

public abstract int edge(int i)

Returns the ith edge ID of this clipped shape. Edges are sorted in increasing order of edge ID. The edge IDs may be passed to the corresponding shape's S2Shape.getEdge(int, com.google.common.geometry.S2Shape.MutableEdge) method.

Parameters:

i - must be at least 0 and less than numEdges()

containsEdge

public final boolean containsEdge(int edgeId)

Returns whether the clipped shape contains the given edge id.

numShapes

public final int numShapes()

For implementing the Cell interface, this class contains just 1 shape (itself.)

Specified by:

numShapes in class S2ShapeIndex.Cell

clipped

public final S2ShapeIndex.S2ClippedShape clipped(int i)

For implementing the Cell interface, this class contains just 1 shape (itself.)

Specified by:

clipped in class S2ShapeIndex.Cell

Parameters:

i - must be at least 0 and less than S2ShapeIndex.Cell.numShapes()