347 lines
8.8 KiB
Java
347 lines
8.8 KiB
Java
package shape;
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import java.awt.*;
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import java.awt.event.*;
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import java.awt.geom.*;
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import java.util.*;
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import javax.swing.*;
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/**
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* This program demonstrates the various 2D shapes.
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* @version 1.03 2016-05-10
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* @author Cay Horstmann
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*/
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public class ShapeTest
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{
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public static void main(String[] args)
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{
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EventQueue.invokeLater(() ->
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{
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JFrame frame = new ShapeTestFrame();
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frame.setTitle("ShapeTest");
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frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
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frame.setVisible(true);
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});
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}
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}
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/**
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* This frame contains a combo box to select a shape and a component to draw it.
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*/
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class ShapeTestFrame extends JFrame
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{
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public ShapeTestFrame()
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{
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final ShapeComponent comp = new ShapeComponent();
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add(comp, BorderLayout.CENTER);
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final JComboBox<ShapeMaker> comboBox = new JComboBox<>();
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comboBox.addItem(new LineMaker());
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comboBox.addItem(new RectangleMaker());
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comboBox.addItem(new RoundRectangleMaker());
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comboBox.addItem(new EllipseMaker());
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comboBox.addItem(new ArcMaker());
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comboBox.addItem(new PolygonMaker());
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comboBox.addItem(new QuadCurveMaker());
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comboBox.addItem(new CubicCurveMaker());
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comboBox.addActionListener(event ->
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{
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ShapeMaker shapeMaker = comboBox.getItemAt(comboBox.getSelectedIndex());
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comp.setShapeMaker(shapeMaker);
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});
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add(comboBox, BorderLayout.NORTH);
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comp.setShapeMaker((ShapeMaker) comboBox.getItemAt(0));
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pack();
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}
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}
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/**
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* This component draws a shape and allows the user to move the points that define it.
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*/
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class ShapeComponent extends JComponent
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{
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private static final Dimension PREFERRED_SIZE = new Dimension(300, 200);
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private Point2D[] points;
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private static Random generator = new Random();
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private static int SIZE = 10;
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private int current;
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private ShapeMaker shapeMaker;
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public ShapeComponent()
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{
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addMouseListener(new MouseAdapter()
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{
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public void mousePressed(MouseEvent event)
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{
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Point p = event.getPoint();
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for (int i = 0; i < points.length; i++)
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{
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double x = points[i].getX() - SIZE / 2;
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double y = points[i].getY() - SIZE / 2;
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Rectangle2D r = new Rectangle2D.Double(x, y, SIZE, SIZE);
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if (r.contains(p))
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{
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current = i;
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return;
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}
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}
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}
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public void mouseReleased(MouseEvent event)
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{
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current = -1;
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}
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});
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addMouseMotionListener(new MouseMotionAdapter()
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{
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public void mouseDragged(MouseEvent event)
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{
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if (current == -1) return;
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points[current] = event.getPoint();
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repaint();
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}
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});
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current = -1;
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}
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/**
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* Set a shape maker and initialize it with a random point set.
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* @param aShapeMaker a shape maker that defines a shape from a point set
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*/
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public void setShapeMaker(ShapeMaker aShapeMaker)
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{
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shapeMaker = aShapeMaker;
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int n = shapeMaker.getPointCount();
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points = new Point2D[n];
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for (int i = 0; i < n; i++)
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{
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double x = generator.nextDouble() * getWidth();
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double y = generator.nextDouble() * getHeight();
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points[i] = new Point2D.Double(x, y);
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}
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repaint();
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}
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public void paintComponent(Graphics g)
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{
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if (points == null) return;
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Graphics2D g2 = (Graphics2D) g;
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for (int i = 0; i < points.length; i++)
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{
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double x = points[i].getX() - SIZE / 2;
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double y = points[i].getY() - SIZE / 2;
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g2.fill(new Rectangle2D.Double(x, y, SIZE, SIZE));
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}
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g2.draw(shapeMaker.makeShape(points));
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}
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public Dimension getPreferredSize() { return PREFERRED_SIZE; }
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}
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/**
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* A shape maker can make a shape from a point set. Concrete subclasses must return a shape in the
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* makeShape method.
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*/
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abstract class ShapeMaker
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{
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private int pointCount;
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/**
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* Constructs a shape maker.
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* @param ointCount the number of points needed to define this shape.
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*/
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public ShapeMaker(int pointCount)
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{
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this.pointCount = pointCount;
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}
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/**
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* Gets the number of points needed to define this shape.
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* @return the point count
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*/
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public int getPointCount()
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{
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return pointCount;
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}
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/**
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* Makes a shape out of the given point set.
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* @param p the points that define the shape
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* @return the shape defined by the points
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*/
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public abstract Shape makeShape(Point2D[] p);
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public String toString()
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{
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return getClass().getName();
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}
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}
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/**
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* Makes a line that joins two given points.
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*/
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class LineMaker extends ShapeMaker
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{
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public LineMaker()
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{
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super(2);
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}
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public Shape makeShape(Point2D[] p)
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{
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return new Line2D.Double(p[0], p[1]);
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}
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}
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/**
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* Makes a rectangle that joins two given corner points.
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*/
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class RectangleMaker extends ShapeMaker
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{
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public RectangleMaker()
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{
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super(2);
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}
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public Shape makeShape(Point2D[] p)
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{
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Rectangle2D s = new Rectangle2D.Double();
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s.setFrameFromDiagonal(p[0], p[1]);
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return s;
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}
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}
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/**
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* Makes a round rectangle that joins two given corner points.
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*/
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class RoundRectangleMaker extends ShapeMaker
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{
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public RoundRectangleMaker()
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{
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super(2);
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}
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public Shape makeShape(Point2D[] p)
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{
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RoundRectangle2D s = new RoundRectangle2D.Double(0, 0, 0, 0, 20, 20);
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s.setFrameFromDiagonal(p[0], p[1]);
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return s;
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}
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}
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/**
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* Makes an ellipse contained in a bounding box with two given corner points.
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*/
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class EllipseMaker extends ShapeMaker
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{
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public EllipseMaker()
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{
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super(2);
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}
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public Shape makeShape(Point2D[] p)
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{
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Ellipse2D s = new Ellipse2D.Double();
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s.setFrameFromDiagonal(p[0], p[1]);
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return s;
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}
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}
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/**
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* Makes an arc contained in a bounding box with two given corner points, and with starting and
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* ending angles given by lines emanating from the center of the bounding box and ending in two
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* given points. To show the correctness of the angle computation, the returned shape contains the
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* arc, the bounding box, and the lines.
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*/
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class ArcMaker extends ShapeMaker
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{
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public ArcMaker()
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{
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super(4);
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}
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public Shape makeShape(Point2D[] p)
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{
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double centerX = (p[0].getX() + p[1].getX()) / 2;
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double centerY = (p[0].getY() + p[1].getY()) / 2;
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double width = Math.abs(p[1].getX() - p[0].getX());
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double height = Math.abs(p[1].getY() - p[0].getY());
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double skewedStartAngle = Math.toDegrees(Math.atan2(-(p[2].getY() - centerY) * width,
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(p[2].getX() - centerX) * height));
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double skewedEndAngle = Math.toDegrees(Math.atan2(-(p[3].getY() - centerY) * width,
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(p[3].getX() - centerX) * height));
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double skewedAngleDifference = skewedEndAngle - skewedStartAngle;
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if (skewedStartAngle < 0) skewedStartAngle += 360;
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if (skewedAngleDifference < 0) skewedAngleDifference += 360;
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Arc2D s = new Arc2D.Double(0, 0, 0, 0, skewedStartAngle, skewedAngleDifference, Arc2D.OPEN);
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s.setFrameFromDiagonal(p[0], p[1]);
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GeneralPath g = new GeneralPath();
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g.append(s, false);
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Rectangle2D r = new Rectangle2D.Double();
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r.setFrameFromDiagonal(p[0], p[1]);
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g.append(r, false);
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Point2D center = new Point2D.Double(centerX, centerY);
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g.append(new Line2D.Double(center, p[2]), false);
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g.append(new Line2D.Double(center, p[3]), false);
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return g;
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}
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}
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/**
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* Makes a polygon defined by six corner points.
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*/
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class PolygonMaker extends ShapeMaker
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{
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public PolygonMaker()
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{
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super(6);
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}
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public Shape makeShape(Point2D[] p)
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{
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GeneralPath s = new GeneralPath();
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s.moveTo((float) p[0].getX(), (float) p[0].getY());
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for (int i = 1; i < p.length; i++)
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s.lineTo((float) p[i].getX(), (float) p[i].getY());
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s.closePath();
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return s;
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}
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}
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/**
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* Makes a quad curve defined by two end points and a control point.
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*/
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class QuadCurveMaker extends ShapeMaker
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{
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public QuadCurveMaker()
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{
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super(3);
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}
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public Shape makeShape(Point2D[] p)
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{
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return new QuadCurve2D.Double(p[0].getX(), p[0].getY(), p[1].getX(), p[1].getY(),
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p[2].getX(), p[2].getY());
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}
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}
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/**
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* Makes a cubic curve defined by two end points and two control points.
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*/
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class CubicCurveMaker extends ShapeMaker
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{
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public CubicCurveMaker()
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{
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super(4);
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}
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public Shape makeShape(Point2D[] p)
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{
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return new CubicCurve2D.Double(p[0].getX(), p[0].getY(), p[1].getX(), p[1].getY(), p[2]
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.getX(), p[2].getY(), p[3].getX(), p[3].getY());
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}
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}
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