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/*******************************************************************************
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* Copyright (c) 2004, 2010 IBM Corporation and others.
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* All rights reserved. This program and the accompanying materials
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* are made available under the terms of the Eclipse Public License v1.0
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* which accompanies this distribution, and is available at
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* http://www.eclipse.org/legal/epl-v10.html
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*
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* Contributors:
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* IBM Corporation - initial API and implementation
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*******************************************************************************/
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package org.eclipse.draw2d.graph;
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import org.eclipse.draw2d.geometry.Geometry;
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import org.eclipse.draw2d.geometry.Point;
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/**
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* A Segment representation for the ShortestPathRouting. A segment is a line
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* between two vertices.
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*
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* This class is for internal use only
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*
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* @author Whitney Sorenson
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* @since 3.0
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*/
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class Segment {
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Vertex start, end;
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/**
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* Creates a segment between the given start and end points.
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*
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* @param start
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* the start vertex
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* @param end
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* the end vertex
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*/
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Segment(Vertex start, Vertex end) {
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this.start = start;
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this.end = end;
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}
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/**
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* Returns the cosine of the made between this segment and the given segment
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*
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* @param otherSegment
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* the other segment
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* @return cosine value (not arc-cos)
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*/
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double cosine(Segment otherSegment) {
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double cos = (((start.x - end.x) * (otherSegment.end.x - otherSegment.start.x)) + ((start.y - end.y) * (otherSegment.end.y - otherSegment.start.y)))
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/ (getLength() * otherSegment.getLength());
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double sin = (((start.x - end.x) * (otherSegment.end.y - otherSegment.start.y)) - ((start.y - end.y) * (otherSegment.end.x - otherSegment.start.x)));
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if (sin < 0.0)
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return (1 + cos);
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return -(1 + cos);
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}
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/**
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* Returns the cross product of this segment and the given segment
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*
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* @param otherSegment
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* the other segment
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* @return the cross product
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*/
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long crossProduct(Segment otherSegment) {
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return (((start.x - end.x) * (otherSegment.end.y - end.y)) - ((start.y - end.y) * (otherSegment.end.x - end.x)));
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}
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private double getLength() {
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return (end.getDistance(start));
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}
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/**
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* Returns a number that represents the sign of the slope of this segment.
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* It does not return the actual slope.
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*
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* @return number representing sign of the slope
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*/
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double getSlope() {
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if (end.x - start.x >= 0)
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return (end.y - start.y);
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else
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return -(end.y - start.y);
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}
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/**
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* Returns true if the given segment intersects this segment.
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*
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* @param sx
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* start x
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* @param sy
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* start y
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* @param tx
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* end x
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* @param ty
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* end y
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* @return true if the segments intersect
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*/
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boolean intersects(int sx, int sy, int tx, int ty) {
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return Geometry.linesIntersect(start.x, start.y, end.x, end.y, sx, sy,
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tx, ty);
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}
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/**
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* Return true if the segment represented by the points intersects this
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* segment.
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*
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* @param s
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* start point
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* @param t
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* end point
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* @return true if the segments intersect
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*/
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boolean intersects(Point s, Point t) {
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return intersects(s.x, s.y, t.x, t.y);
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}
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/**
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* @see java.lang.Object#toString()
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*/
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public String toString() {
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return start + "---" + end; //$NON-NLS-1$
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}
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}
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