drawingpanel.java

一个大学本科java课程的大作业。要求利用GUI以及APPLET分别完成一个任务:随机产生三角形

/**
 *Title:DrawingPanel.java
 *Descriprion:This class is a subclass of JPanel.
 *It is modified by the class DisplayShapes and 
 *also prints out the shapes as well as their area and perimeter.
 *@author: Peng yu
 */



import javax.swing.*;
import java.awt.*;


public class DrawingPanel extends JPanel 
{

	public static int numberOfShape;       //the total number of drawn shapes
	public static int countRect;           //the number of generated rectangles
	public static int countTri;            //the number of generated triangles
        public static int xPoint;
        public static int yPoint;              //the coordinary
    
    
    
    
        /**
	 * This method just initialises the parameters
	 * and determines the number of rectangles and triangles by random
	 */	
	public void init()
	{
		
		numberOfShape=0;
		countRect = (int) (1 + Math.random() * 3);
		countTri  = (int) (1 + Math.random() * 3);
		xPoint=15;
		yPoint=15;
	
	}
	
	
	

	
	/**
	 * This method paint the shapes out.It calls three methods
	 * @param g is an object of graphics
	 */
        public void paintComponent(Graphics g) 
	{
    	
    	        init();                    //call the init to reset the panel
    	        g.setColor(Color.white);   //repaint the background of the frame 
		
    	
		for (int i = 1; i <= countRect; i++)     //generate "countRect" rectangles
		{
			try 
			{
				Rectangle rect = new Rectangle();    
				paintRect(g,rect);      //call the paintRect method to paint rectangle
				numberOfShape++;
				yPoint =yPoint+rect.getHeight()+30;

			} catch (IllegalRectangleException e) {
			        System.err.println(e.getMessage()); 
			      
                                //Print the message of the IllegalRectangleException
			
                        }
			
		}


		for (int i = 1; i <= countTri; i++)    //generate "countTri" triangles
		{
			try 
			{ 
				Triangle tri = new Triangle();          
				paintTri(g,tri);      //Call the paintTri method to paint triangles
				numberOfShape++;
				yPoint=yPoint+tri.getHeight()+30;
			
			} catch (IllegalTriangleException e) {
				System.err.println(e.getMessage());
                
                                //Print the message of the IllegalTriangleException
			
                        }
				
		}
        

		paintOutcomes(g);    //Call the paintOutcomes method to print the outcomes
		
	}
	
    
    

    
        /**
	 * This method paint the rectangles 
	 * and output the relative parameters such as area as well as perimeter
	 * @param g the object of graphics
	 * @param rect the object of rectangle
	 */
	public static void paintRect(Graphics g,Rectangle rect) 
	{

		g.setColor(Color.blue);
		g.fillRect(xPoint, yPoint, rect.getWidth(), rect.getHeight());
		
		g.setFont(new Font("TimesRoman", Font.PLAIN, 12));      //set the font
		g.setColor(Color.black);

		g.drawString(String.format("Width= %d centimeters    Height= %d centimeters",
                                           rect.getWidth(),rect.getHeight()),
                                                           xPoint+rect.getWidth()+20, yPoint+rect.getHeight()/2);

		g.drawString(String.format("Area= %,4.2f square centimeters.      Perimeter= %,4.2f centimeters.",
                                           rect.calcShapeArea(), rect.calcShapePerimeter()),
                                                           xPoint, yPoint+rect.getHeight()+10);
	
	}
	


	
	
	/**
	 * This method paint the triangles
	 * and output the relative parameters such as area as well as perimeter
	 * @param g the object of graphics
	 * @param tri the object of triangle
	 */
	public static void paintTri(Graphics g,Triangle tri)
	{

		g.setColor(Color.red);
		
		int[] a = { xPoint + tri.getBase() / 2, xPoint, xPoint + tri.getBase() };
		int[] b = { yPoint, yPoint+tri.getHeight(), yPoint + tri.getHeight() };
		g.fillPolygon(a, b, 3);     //print the triangle
		

		g.setColor(Color.black);
		g.drawString(String.format("Base=%d        Height=%d",
                                                tri.getBase(),tri.getHeight()),xPoint+tri.getBase(), yPoint+tri.getHeight()/2);
		
                g.drawString(String.format("Area= %,4.2f square centimeters      Perimeter= %,4.2f centimeters",
                                                tri.calcShapeArea(), tri.calcShapePerimeter()),xPoint, yPoint+tri.getHeight()+10);
	
	}
	
	


	
	/**
	 * This method print out the outcomes such as total number of drawn shapes
	 * @param g the object of graphics
	 */
	public static void paintOutcomes(Graphics g)
	{

		g.setColor(Color.black);
		g.drawString( String.format("The number of rectangles generated (contains illegal ones) is: %d",countRect),xPoint,yPoint+20);
		g.drawString( String.format("The number of triangles generated (contains illegal ones) is: %d",countTri),xPoint,yPoint+35);
		//print out the number of shapes generated (contains illegal ones)
	
		
		g.setFont(new Font("TimesRoman", Font.BOLD, 12));
		
                if (numberOfShape != 0) 
		{	
			g.drawString("The total number of drawn shapes is "+numberOfShape, xPoint, yPoint + 50);
		} 
		
                else 
		{
			g.drawString("No valid shapes were generated. Please try again!",xPoint, yPoint + 50);
		  
		}
	
	}

}