com.revolsys.jts.noding.snapround

Class HotPixel

java.lang.Object

com.revolsys.jts.noding.snapround.HotPixel

public class HotPixel
extends Object

Implements a "hot pixel" as used in the Snap Rounding algorithm. A hot pixel contains the interior of the tolerance square and the boundary minus the top and right segments.

The hot pixel operations are all computed in the integer domain to avoid rounding problems.

Version:

1.7

Constructor Summary

Constructors

Constructor and Description
HotPixel(Point pt, double scaleFactor, LineIntersector li) Creates a new hot pixel, using a given scale factor.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	addSnappedNode(NodedSegmentString segStr, int segIndex) Adds a new node (equal to the snap pt) to the specified segment if the segment passes through the hot pixel
Point	getCoordinate() Gets the coordinate this hot pixel is based at.
BoundingBox	getSafeEnvelope() Returns a "safe" envelope that is guaranteed to contain the hot pixel.
boolean	intersects(Point p0, Point p1) Tests whether the line segment (p0-p1) intersects this hot pixel.

Methods inherited from class java.lang.Object

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

Constructor Detail

HotPixel

public HotPixel(Point pt,
        double scaleFactor,
        LineIntersector li)

Creates a new hot pixel, using a given scale factor. The scale factor must be strictly positive (non-zero).

Parameters:

pt - the coordinate at the centre of the pixel

scaleFactor - the scaleFactor determining the pixel size. Must be > 0

li - the intersector to use for testing intersection with line segments

Method Detail

addSnappedNode

public boolean addSnappedNode(NodedSegmentString segStr,
                     int segIndex)

Adds a new node (equal to the snap pt) to the specified segment if the segment passes through the hot pixel

Parameters:

segStr -

segIndex -

Returns:

true if a node was added to the segment

getCoordinate

public Point getCoordinate()

Gets the coordinate this hot pixel is based at.

Returns:

the coordinate of the pixel

getSafeEnvelope

public BoundingBox getSafeEnvelope()

Returns a "safe" envelope that is guaranteed to contain the hot pixel. The envelope returned will be larger than the exact envelope of the pixel.

Returns:

an envelope which contains the hot pixel

intersects

public boolean intersects(Point p0,
                 Point p1)

Tests whether the line segment (p0-p1) intersects this hot pixel.

Parameters:

p0 - the first coordinate of the line segment to test

p1 - the second coordinate of the line segment to test

Returns:

true if the line segment intersects this hot pixel