/*
* Copyright (c) 2005, the JUNG Project and the Regents of the University of
* California All rights reserved.
*
* This software is open-source under the BSD license; see either "license.txt"
* or http://jung.sourceforge.net/license.txt for a description.
*
* Created on Aug 23, 2005
*/
package edu.uci.ics.jung.visualization.renderers;
import java.awt.Shape;
import java.awt.geom.AffineTransform;
import java.awt.geom.GeneralPath;
import java.awt.geom.Line2D;
import java.awt.geom.PathIterator;
import java.awt.geom.Point2D;
import edu.uci.ics.jung.visualization.RenderContext;
public class CenterEdgeArrowRenderingSupport<V,E> implements EdgeArrowRenderingSupport<V,E> {
/**
* Returns a transform to position the arrowhead on this edge shape at the
* point where it intersects the passed vertex shape.
*/
public AffineTransform getArrowTransform(RenderContext<V,E> rc, Shape edgeShape, Shape vertexShape) {
GeneralPath path = new GeneralPath(edgeShape);
float[] seg = new float[6];
Point2D p1=null;
Point2D p2=null;
AffineTransform at = new AffineTransform();
// count the segments.
int middleSegment = 0;
int current = 0;
for(PathIterator i=path.getPathIterator(null,1); !i.isDone(); i.next()) {
current++;
}
middleSegment = current/2;
// find the middle segment
current = 0;
for(PathIterator i=path.getPathIterator(null,1); !i.isDone(); i.next()) {
current++;
int ret = i.currentSegment(seg);
if(ret == PathIterator.SEG_MOVETO) {
p2 = new Point2D.Float(seg[0],seg[1]);
} else if(ret == PathIterator.SEG_LINETO) {
p1 = p2;
p2 = new Point2D.Float(seg[0],seg[1]);
}
if(current > middleSegment) { // done
at = getArrowTransform(rc, new Line2D.Float(p1,p2),vertexShape);
break;
}
}
return at;
}
/**
* Returns a transform to position the arrowhead on this edge shape at the
* point where it intersects the passed vertex shape.
*/
public AffineTransform getReverseArrowTransform(RenderContext<V,E> rc, Shape edgeShape, Shape vertexShape) {
return getReverseArrowTransform(rc, edgeShape, vertexShape, true);
}
/**
* <p>Returns a transform to position the arrowhead on this edge shape at the
* point where it intersects the passed vertex shape.</p>
*
* <p>The Loop edge is a special case because its staring point is not inside
* the vertex. The passedGo flag handles this case.</p>
*
* @param path
* @param vertexShape
* @param passedGo - used only for Loop edges
*/
public AffineTransform getReverseArrowTransform(RenderContext<V,E> rc, Shape edgeShape, Shape vertexShape,
boolean passedGo) {
GeneralPath path = new GeneralPath(edgeShape);
float[] seg = new float[6];
Point2D p1=null;
Point2D p2=null;
AffineTransform at = new AffineTransform();
// count the segments.
int middleSegment = 0;
int current = 0;
for(PathIterator i=path.getPathIterator(null,1); !i.isDone(); i.next()) {
current++;
}
middleSegment = current/2;
// find the middle segment
current = 0;
for(PathIterator i=path.getPathIterator(null,1); !i.isDone(); i.next()) {
current++;
int ret = i.currentSegment(seg);
if(ret == PathIterator.SEG_MOVETO) {
p2 = new Point2D.Float(seg[0],seg[1]);
} else if(ret == PathIterator.SEG_LINETO) {
p1 = p2;
p2 = new Point2D.Float(seg[0],seg[1]);
}
if(current > middleSegment) { // done
at = getReverseArrowTransform(rc, new Line2D.Float(p1,p2),vertexShape);
break;
}
}
return at;
}
/**
* This is used for the arrow of a directed and for one of the
* arrows for non-directed edges
* Get a transform to place the arrow shape on the passed edge at the
* point where it intersects the passed shape
* @param edgeShape
* @param vertexShape
* @return
*/
public AffineTransform getArrowTransform(RenderContext<V,E> rc, Line2D edgeShape, Shape vertexShape) {
// find the midpoint of the edgeShape line, and use it to make the transform
Line2D left = new Line2D.Float();
Line2D right = new Line2D.Float();
this.subdivide(edgeShape, left, right);
edgeShape = right;
float dx = (float) (edgeShape.getX1()-edgeShape.getX2());
float dy = (float) (edgeShape.getY1()-edgeShape.getY2());
double atheta = Math.atan2(dx,dy)+Math.PI/2;
AffineTransform at =
AffineTransform.getTranslateInstance(edgeShape.getX1(), edgeShape.getY1());
at.rotate(-atheta);
return at;
}
/**
* This is used for the reverse-arrow of a non-directed edge
* get a transform to place the arrow shape on the passed edge at the
* point where it intersects the passed shape
* @param edgeShape
* @param vertexShape
* @return
*/
protected AffineTransform getReverseArrowTransform(RenderContext<V,E> rc, Line2D edgeShape, Shape vertexShape) {
// find the midpoint of the edgeShape line, and use it to make the transform
Line2D left = new Line2D.Float();
Line2D right = new Line2D.Float();
this.subdivide(edgeShape, left, right);
edgeShape = right;
float dx = (float) (edgeShape.getX1()-edgeShape.getX2());
float dy = (float) (edgeShape.getY1()-edgeShape.getY2());
// calculate the angle for the arrowhead
double atheta = Math.atan2(dx,dy)-Math.PI/2;
AffineTransform at = AffineTransform.getTranslateInstance(edgeShape.getX1(),edgeShape.getY1());
at.rotate(-atheta);
return at;
}
/**
* divide a Line2D into 2 new Line2Ds that are returned
* in the passed left and right instances, if non-null
* @param src the line to divide
* @param left the left side, or null
* @param right the right side, or null
*/
protected void subdivide(Line2D src,
Line2D left,
Line2D right) {
double x1 = src.getX1();
double y1 = src.getY1();
double x2 = src.getX2();
double y2 = src.getY2();
double mx = x1 + (x2-x1)/2.0;
double my = y1 + (y2-y1)/2.0;
if (left != null) {
left.setLine(x1, y1, mx, my);
}
if (right != null) {
right.setLine(mx, my, x2, y2);
}
}
}