public class PolygonsSet extends AbstractRegion<Euclidean2D,Euclidean1D>
Region.Location| Constructor and Description |
|---|
PolygonsSet(BSPTree<Euclidean2D> tree,
double tolerance)
Build a polygons set from a BSP tree.
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PolygonsSet(Collection<SubHyperplane<Euclidean2D>> boundary,
double tolerance)
Build a polygons set from a Boundary REPresentation (B-rep).
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PolygonsSet(double tolerance)
Build a polygons set representing the whole plane.
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PolygonsSet(double xMin,
double xMax,
double yMin,
double yMax,
double tolerance)
Build a parallellepipedic box.
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PolygonsSet(double hyperplaneThickness,
Vector2D... vertices)
Build a polygon from a simple list of vertices.
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| Modifier and Type | Method and Description |
|---|---|
PolygonsSet |
buildNew(BSPTree<Euclidean2D> tree)
Build a region using the instance as a prototype.
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protected void |
computeGeometricalProperties()
Compute some geometrical properties.
|
Vector2D[][] |
getVertices()
Get the vertices of the polygon.
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applyTransform, checkPoint, checkPoint, checkPoint, checkPoint, contains, copySelf, getBarycenter, getBoundarySize, getSize, getTolerance, getTree, intersection, isEmpty, isEmpty, isFull, isFull, projectToBoundary, setBarycenter, setBarycenter, setSizepublic PolygonsSet(double tolerance)
tolerance - tolerance below which points are considered identicalpublic PolygonsSet(BSPTree<Euclidean2D> tree, double tolerance)
The leaf nodes of the BSP tree must have a
Boolean attribute representing the inside status of
the corresponding cell (true for inside cells, false for outside
cells). In order to avoid building too many small objects, it is
recommended to use the predefined constants
Boolean.TRUE and Boolean.FALSE
This constructor is aimed at expert use, as building the tree may
be a difficult task. It is not intended for general use and for
performances reasons does not check thoroughly its input, as this would
require walking the full tree each time. Failing to provide a tree with
the proper attributes, will therefore generate problems like
NullPointerException or ClassCastException only later on.
This limitation is known and explains why this constructor is for expert
use only. The caller does have the responsibility to provided correct arguments.
tree - inside/outside BSP tree representing the regiontolerance - tolerance below which points are considered identicalpublic PolygonsSet(Collection<SubHyperplane<Euclidean2D>> boundary, double tolerance)
The boundary is provided as a collection of sub-hyperplanes. Each sub-hyperplane has the
interior part of the region on its minus side and the exterior on
its plus side.
The boundary elements can be in any order, and can form
several non-connected sets (like for example polygons with holes
or a set of disjoint polygons considered as a whole). In
fact, the elements do not even need to be connected together
(their topological connections are not used here). However, if the
boundary does not really separate an inside open from an outside
open (open having here its topological meaning), then subsequent
calls to the checkPoint method will not be meaningful anymore.
If the boundary is empty, the region will represent the whole space.
boundary - collection of boundary elements, as a
collection of SubHyperplane objectstolerance - tolerance below which points are considered identicalpublic PolygonsSet(double xMin,
double xMax,
double yMin,
double yMax,
double tolerance)
xMin - low bound along the x directionxMax - high bound along the x directionyMin - low bound along the y directionyMax - high bound along the y directiontolerance - tolerance below which points are considered identicalpublic PolygonsSet(double hyperplaneThickness,
Vector2D... vertices)
The boundary is provided as a list of points considering to represent the vertices of a simple loop. The interior part of the region is on the left side of this path and the exterior is on its right side.
This constructor does not handle polygons with a boundary forming several disconnected paths (such as polygons with holes).
For cases where this simple constructor applies, it is expected to
be numerically more robust than the general
constructor using subhyperplanes.
If the list is empty, the region will represent the whole space.
Polygons with thin pikes or dents are inherently difficult to handle because
they involve lines with almost opposite directions at some vertices. Polygons
whose vertices come from some physical measurement with noise are also
difficult because an edge that should be straight may be broken in lots of
different pieces with almost equal directions. In both cases, computing the
lines intersections is not numerically robust due to the almost 0 or almost
π angle. Such cases need to carefully adjust the hyperplaneThickness
parameter. A too small value would often lead to completely wrong polygons
with large area wrongly identified as inside or outside. Large values are
often much safer. As a rule of thumb, a value slightly below the size of the
most accurate detail needed is a good value for the hyperplaneThickness
parameter.
hyperplaneThickness - tolerance below which points are considered to
belong to the hyperplane (which is therefore more a slab)vertices - vertices of the simple loop boundarypublic PolygonsSet buildNew(BSPTree<Euclidean2D> tree)
This method allow to create new instances without knowing exactly the type of the region. It is an application of the prototype design pattern.
The leaf nodes of the BSP tree must have a
Boolean attribute representing the inside status of
the corresponding cell (true for inside cells, false for outside
cells). In order to avoid building too many small objects, it is
recommended to use the predefined constants
Boolean.TRUE and Boolean.FALSE. The
tree also must have either null internal nodes or
internal nodes representing the boundary as specified in the
getTree method).
buildNew in interface Region<Euclidean2D>buildNew in class AbstractRegion<Euclidean2D,Euclidean1D>tree - inside/outside BSP tree representing the new regionprotected void computeGeometricalProperties()
The properties to compute are the barycenter and the size.
computeGeometricalProperties in class AbstractRegion<Euclidean2D,Euclidean1D>public Vector2D[][] getVertices()
The polygon boundary can be represented as an array of loops, each loop being itself an array of vertices.
In order to identify open loops which start and end by infinite edges, the open loops arrays start with a null point. In this case, the first non null point and the last point of the array do not represent real vertices, they are dummy points intended only to get the direction of the first and last edge. An open loop consisting of a single infinite line will therefore be represented by a three elements array with one null point followed by two dummy points. The open loops are always the first ones in the loops array.
If the polygon has no boundary at all, a zero length loop array will be returned.
All line segments in the various loops have the inside of the region on their left side and the outside on their right side when moving in the underlying line direction. This means that closed loops surrounding finite areas obey the direct trigonometric orientation.
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