如何创建平行四边形/菱形jpanels？

Question

我正在创建简单的流程图软件。我想创建椭圆/平行四边形/菱形/矩形形状。我想调整这些形状的大小并拖动那些形状。因为调整大小我不能使用图像。我将拖动事件添加到矩形形状japanel但我无法使用jpanel创建其他形状。如何在jpanel中添加平行四边形/菱形？

给出＆＃34;在jsplitpane中调整jscrollpane中画布的问题＆＃34;我不想回答平行四边形和钻石形状的问题 也创造这些形状

/ * ResizableComponent.java * /

import java.awt.Color;
import java.awt.Dimension;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

import javax.swing.JFrame;
import javax.swing.JPanel;


/* ResizableComponent.java */

public class ResizableComponent extends JFrame {

  private JPanel panel = new JPanel(null);
  private Resizable resizer;


  public ResizableComponent() {

      add(panel);

      JPanel area = new JPanel(); 
      area.setBackground(Color.white);
      resizer = new Resizable(area);
      resizer.setBounds(50, 30, 200, 150);
      panel.add(resizer);


      setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      setSize(new Dimension(350, 300));
      setTitle("Resizable Component");
      setLocationRelativeTo(null);

      addMouseListener(new MouseAdapter() {
        public void mousePressed(MouseEvent me) {

          requestFocus();
          resizer.repaint();
        }
      });
  }

  public static void main(String[] args) {
      ResizableComponent rc = new ResizableComponent();
      rc.setVisible(true);
  }
}

// Resizable.java

import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Cursor;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.event.MouseEvent;

import javax.swing.JComponent;
import javax.swing.event.MouseInputAdapter;
import javax.swing.event.MouseInputListener;

// Resizable.java 

public class Resizable extends JComponent {

  public Resizable(Component comp) {
    this(comp, new ResizableBorder(8));
  }

  public Resizable(Component comp, ResizableBorder border) {
    setLayout(new BorderLayout());
    add(comp);
    addMouseListener(resizeListener);
    addMouseMotionListener(resizeListener);
    setBorder(border);
  }

  private void resize() {
      if (getParent() != null) {
        ((JComponent)getParent()).revalidate();
      }
  }

  MouseInputListener resizeListener = new MouseInputAdapter() {
    public void mouseMoved(MouseEvent me) {
      if (hasFocus()) {
          ResizableBorder border = (ResizableBorder)getBorder();
          setCursor(Cursor.getPredefinedCursor(border.getCursor(me)));
      }
    }

    public void mouseExited(MouseEvent mouseEvent) {
       setCursor(Cursor.getDefaultCursor());
    }

    private int cursor;
    private Point startPos = null;

    public void mousePressed(MouseEvent me) {
      ResizableBorder border = (ResizableBorder)getBorder();
      cursor = border.getCursor(me);
      startPos = me.getPoint();
      requestFocus();
      repaint();
    }

    public void mouseDragged(MouseEvent me) {

      if (startPos != null) {

        int x = getX();
        int y = getY();
        int w = getWidth();
        int h = getHeight();

        int dx = me.getX() - startPos.x;
        int dy = me.getY() - startPos.y;

        switch (cursor) {
          case Cursor.N_RESIZE_CURSOR:
            if (!(h - dy < 50)) {
              setBounds(x, y + dy, w, h - dy);
              resize();
            }
            break;

          case Cursor.S_RESIZE_CURSOR:
            if (!(h + dy < 50)) {
              setBounds(x, y, w, h + dy);
              startPos = me.getPoint();
              resize();
            }
            break;

          case Cursor.W_RESIZE_CURSOR:
            if (!(w - dx < 50)) {
              setBounds(x + dx, y, w - dx, h);
              resize();
            }
            break;

          case Cursor.E_RESIZE_CURSOR:
            if (!(w + dx < 50)) {
              setBounds(x, y, w + dx, h);
              startPos = me.getPoint();
              resize();
            }
            break;

          case Cursor.NW_RESIZE_CURSOR:
            if (!(w - dx < 50) && !(h - dy < 50)) {
              setBounds(x + dx, y + dy, w - dx, h - dy);
              resize();
            }
            break;

          case Cursor.NE_RESIZE_CURSOR:
            if (!(w + dx < 50) && !(h - dy < 50)) {
              setBounds(x, y + dy, w + dx, h - dy);
              startPos = new Point(me.getX(), startPos.y);
              resize();
            }
            break;

          case Cursor.SW_RESIZE_CURSOR:
            if (!(w - dx < 50) && !(h + dy < 50)) {
              setBounds(x + dx, y, w - dx, h + dy);
              startPos = new Point(startPos.x, me.getY());
              resize();
            }
            break;

          case Cursor.SE_RESIZE_CURSOR:
            if (!(w + dx < 50) && !(h + dy < 50)) {
              setBounds(x, y, w + dx, h + dy);
              startPos = me.getPoint();
              resize();
            }
          break;

          case Cursor.MOVE_CURSOR:
            Rectangle bounds = getBounds();
            bounds.translate(dx, dy);
            setBounds(bounds);
            resize();
          }


          setCursor(Cursor.getPredefinedCursor(cursor));
        }
     }

   public void mouseReleased(MouseEvent mouseEvent) {
     startPos = null;
    }
  };
}

// ResizableBorder.java

import java.awt.Color;
import java.awt.Component;
import java.awt.Cursor;
import java.awt.Graphics;
import java.awt.Insets;
import java.awt.Rectangle;
import java.awt.event.MouseEvent;

import javax.swing.SwingConstants;
import javax.swing.border.Border;

// ResizableBorder.java 

public class ResizableBorder implements Border {
  private int dist = 8;

  int locations[] = 
  {
    SwingConstants.NORTH, SwingConstants.SOUTH, SwingConstants.WEST,
    SwingConstants.EAST, SwingConstants.NORTH_WEST,
    SwingConstants.NORTH_EAST, SwingConstants.SOUTH_WEST,
    SwingConstants.SOUTH_EAST
  };

  int cursors[] =
  { 
    Cursor.N_RESIZE_CURSOR, Cursor.S_RESIZE_CURSOR, Cursor.W_RESIZE_CURSOR,
    Cursor.E_RESIZE_CURSOR, Cursor.NW_RESIZE_CURSOR, Cursor.NE_RESIZE_CURSOR,
    Cursor.SW_RESIZE_CURSOR, Cursor.SE_RESIZE_CURSOR
  };

  public ResizableBorder(int dist) {
    this.dist = dist;
  }

  public Insets getBorderInsets(Component component) {
      return new Insets(dist, dist, dist, dist);
  }

  public boolean isBorderOpaque() {
      return false;
  }

  public void paintBorder(Component component, Graphics g, int x, int y,
                          int w, int h) {
      g.setColor(Color.black);
      g.drawRect(x + dist / 2, y + dist / 2, w - dist, h - dist);

      if (component.hasFocus()) {


        for (int i = 0; i < locations.length; i++) {
          Rectangle rect = getRectangle(x, y, w, h, locations[i]);
          g.setColor(Color.WHITE);
          g.fillRect(rect.x, rect.y, rect.width - 1, rect.height - 1);
          g.setColor(Color.BLACK);
          g.drawRect(rect.x, rect.y, rect.width - 1, rect.height - 1);
        }
      }
  }

  private Rectangle getRectangle(int x, int y, int w, int h, int location) {
      switch (location) {
      case SwingConstants.NORTH:
          return new Rectangle(x + w / 2 - dist / 2, y, dist, dist);
      case SwingConstants.SOUTH:
          return new Rectangle(x + w / 2 - dist / 2, y + h - dist, dist,
                               dist);
      case SwingConstants.WEST:
          return new Rectangle(x, y + h / 2 - dist / 2, dist, dist);
      case SwingConstants.EAST:
          return new Rectangle(x + w - dist, y + h / 2 - dist / 2, dist,
                               dist);
      case SwingConstants.NORTH_WEST:
          return new Rectangle(x, y, dist, dist);
      case SwingConstants.NORTH_EAST:
          return new Rectangle(x + w - dist, y, dist, dist);
      case SwingConstants.SOUTH_WEST:
          return new Rectangle(x, y + h - dist, dist, dist);
      case SwingConstants.SOUTH_EAST:
          return new Rectangle(x + w - dist, y + h - dist, dist, dist);
      }
      return null;
  }

  public int getCursor(MouseEvent me) {
      Component c = me.getComponent();
      int w = c.getWidth();
      int h = c.getHeight();

      for (int i = 0; i < locations.length; i++) {
          Rectangle rect = getRectangle(0, 0, w, h, locations[i]);
          if (rect.contains(me.getPoint()))
              return cursors[i];
      }

      return Cursor.MOVE_CURSOR;
  }
}