get Adjacent Line - Java 2D Graphics

Java examples for 2D Graphics:Line

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Description

get Adjacent Line

Demo Code


//package com.java2s;

import java.awt.Shape;

import java.awt.geom.Line2D;
import java.awt.geom.PathIterator;
import java.awt.geom.Point2D;

public class Main {
    /**/*from w  ww.j  ava 2s  .c  o m*/
     * @param iterator
     * @param shape
     * @return
     */
    public static Line2D getAdjacentLine(PathIterator iterator, Shape shape) {
        Point2D point1 = null;
        Point2D point2 = null;
        float[] segment = new float[6];

        for (; !iterator.isDone(); iterator.next()) {
            int type = iterator.currentSegment(segment);
            if (type != PathIterator.SEG_MOVETO
                    && type != PathIterator.SEG_LINETO) {
                continue;
            }

            point1 = point2;
            point2 = new Point2D.Float(segment[0], segment[1]);

            if (point1 != null && !shape.contains(point1)
                    && shape.contains(point2)) {
                Line2D line = new Line2D.Float(point1, point2);
                Point2D pointOnBoundary = getPointOnBoundary(line, shape);

                line.setLine(point1, pointOnBoundary);
                return line;
            }
        }

        return null;
    }

    /**
     * get intersection point 
     * @param line
     * @param shape
     * @return
     */
    public static Point2D getPointOnBoundary(Line2D line, Shape shape) {

        double leftX = line.getX1();
        double leftY = line.getY1();
        double rightX = line.getX2();
        double rightY = line.getY2();

        //        double h = shape.getBounds2D().getHeight();
        //        double w = shape.getBounds2D().getWidth();
        //        double lh = line.getBounds2D().getHeight();
        //        double lw = line.getBounds2D().getWidth();
        //        double lf = lh > lw ? lh : lw;
        //        double f = h > w? h :w;
        //        double factor = lf < f ? lf : f;
        //        
        //        if( factor == 0 ) factor = 2;

        double factor = 10;

        // shape contains line or shape do not intersect line  
        if (shape.contains(leftX, leftY) == shape.contains(rightX, rightY)) {
            //throw new IllegalArgumentException();
            return null;
        }

        if (shape.contains(leftX, leftY)) {
            double temp;

            // swap
            temp = leftX;
            leftX = rightX;
            rightX = temp;

            // swap
            temp = leftY;
            leftY = rightY;
            rightY = temp;
        }

        double tolerance = 1;//1.0;
        double centerX = leftX + (rightX - leftX) / factor;
        double centerY = leftY + (rightY - leftY) / factor;
        while (Math.abs(rightX - centerX) > tolerance
                || Math.abs(rightY - centerY) > tolerance) {
            if (shape.contains(centerX, centerY)) {
                rightX = centerX;
                rightY = centerY;
            } else {
                leftX = centerX;
                leftY = centerY;
            }

            centerX = leftX + (rightX - leftX) / factor;
            centerY = leftY + (rightY - leftY) / factor;
        }

        return new Point2D.Double(centerX, centerY);
    }
}

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