构造图像，线段，矩形，椭圆，圆角矩形

package thinking;import java.awt.*;import javax.swing.*;public class My extends JFrame{public My(){setLayout(new GridLayout(2,3,5,5));add(new FigurePanel(FigurePanel.LINE));//FigurePanel是自己定义的类，调用FigurePanel中的构造方法add(new FigurePanel(FigurePanel.RECTANGLE));add(new FigurePanel(FigurePanel.ROUND_RECTANGLE));add(new FigurePanel(FigurePanel.OVAL,true));add(new FigurePanel(FigurePanel.RECTANGLE,true));add(new FigurePanel(FigurePanel.ROUND_RECTANGLE,true));}public static void main(String[] args){My frame = new My();frame.setTitle("xx");frame.setSize(600,300);frame.setDefaultCloSEOperation(JFrame.EXIT_ON_CLOSE);frame.setLocationRelativeTo(null);frame.setVisible(true);}}  class FigurePanel extends JPanel { //构建FigurePanel类          // 定义常量    public static final int LINE = 1;    public static final int RECTANGLE = 2;    public static final int ROUND_RECTANGLE = 3;    public static final int OVAL = 4;    PRivate int type = 1;    private boolean filled = false;    public FigurePanel()//无参构造方法    {      }          public FigurePanel(int type)    {        this.type = type;    }        public FigurePanel(int type, boolean filled)    {          this.type = type;          this.filled = filled;      }            public void paintComponent(Graphics g)  //方法    {          super.paintComponents(g);                    int width = getWidth();        int height = getHeight();                  System.out.println("width = " + width + " heigth = "+ height);          System.out.println("width = " + ((int)width*0.1) + " heigth = "+ height);                        switch (type)  //类型        {          case LINE:  //LINE类型时的行为        {              g.setColor(Color.YELLOW);              g.drawLine(10, 10, width - 10, height - 10);              g.drawLine(width - 10, 10, 10, height - 10);             break;        }          case RECTANGLE:  //RECTANGLE类型时的行为        {              g.setColor(Color.BLUE);//颜色            if (filled)  //是否填充            {                  g.fillRect((int)(0.1*width), (int)(0.1 * height), (int)(0.8 *width), (int)(0.8*height));              }              else              {                  g.drawRect((int)(0.1*width), (int)(0.1 * height), (int)(0.8 *width), (int)(0.8*height));              }            break;        }          case ROUND_RECTANGLE:  //圆角矩形        {              g.setColor(Color.RED);              if (filled)              {                  g.fillRoundRect((int)(0.1*width), (int)(0.1 * height), (int)(0.8 *width), (int)(0.8*height), 40, 40);              }              else              {                  g.drawRoundRect((int)(0.1*width), (int)(0.1 * height), (int)(0.8 *width), (int)(0.8*height), 40, 40);              }            break;        }        case OVAL://椭圆        {            g.setColor(Color.BLACK);              if (filled)            {                  g.fillOval((int)(0.1*width), (int)(0.1 * height), (int)(0.8 *width), (int)(0.8*height));              }            else            {                g.drawOval((int)(0.1*width), (int)(0.1 * height), (int)(0.8 *width), (int)(0.8*height));              }        }        }    }          public void setType(int type)    {        this.type = type;        repaint();//repaint方法调用会引起paintComponent方法被调用。repaint方法被调用以刷新视图区域    }    public int getType()    {        return type;    }        public void setFilled(boolean filled)    {        this.filled = filled;         repaint();//repaint方法调用会引起paintComponent方法被调用。repaint方法被调用以刷新视图区域    }        public boolean isFilled()      {          return filled;      }          public Dimension getPreferredSize()    {        return new Dimension(10, 10);      }  }