Java 小畫家(繪圖版) 手把手教學－溫暖午後的金針田__孕育有趣的創新

用Java製作小畫家～

本程式碼製作的小畫家有以下功能：畫筆(直線、點、方塊)、顏色(預設左鍵黑、預設右鍵白、每一刻都隨機色彩、使用者RGB自訂)、清空畫布

目前瑕疵：方塊功能只可以由左上往又下拉

import java.awt.*;
import java.awt.event.*;

public class painter extends Frame implements WindowListener, MouseMotionListener, MouseListener, ActionListener{

   int mx=0,my=0,mx1=0,my1=0,mx2=0,my2=0;/*mouse location*/ /*存取滑鼠位置變數*/
   int mode=0;Boolean clr=false, rb = false; /*用於按鈕判斷模式的變數*/
   int mbt=0; /*存取滑鼠左右鍵的變數*/
   Button bt = null, bt2=null, bt3=null, bt4=null; /*按鈕*/
   TextField th_r = null, th_g = null, th_b = null; /*使用者輸入框用來輸入RGB數值*/
   Color cr = new Color(0,0,0); /*顏色變數預設黑*/
   Color wht = new Color(255,255,255); /*顏色變數白色*/

/*建構子*/
painter(){

/*視窗設定*/
       this.setSize(900, 800);
       this.setLocation(500,50);
       this.setLayout(null);

/*按鈕設定*/
       bt = new Button("Rect mode");
       bt.setSize(80, 50);
       bt.setLocation(100,50);
       bt.addActionListener(this);

       bt2 = new Button("Clean all");
       bt2.setSize(80, 50);
       bt2.setLocation(200,50);
       bt2.addActionListener(this);

       bt3 = new Button("Rainbow mode");
       bt3.setSize(100, 50);
       bt3.setLocation(100,300);
       bt3.addActionListener(this);

       bt4 = new Button("Set color");
       bt4.setSize(80, 50);
       bt4.setLocation(100,250);
       bt4.addActionListener(this);

/*RGB輸入框設定*/
       th_r = new TextField(3);
       th_r.setSize(80,50);
       th_r.setLocation(100, 100);

       th_g = new TextField(3);
       th_g.setSize(80,50);
       th_g.setLocation(100, 150);

       th_b = new TextField(3);
       th_b.setSize(80,50);
       th_b.setLocation(100, 200);

/*顯示與新增物件至此建構子*/
       this.addWindowListener(this);
       this.addMouseMotionListener(this);
       this.addMouseListener(this);
       this.add(bt);
       this.add(bt2);
       this.add(bt3);
       this.add(bt4);
       this.add(th_r);
       this.add(th_g);
       this.add(th_b);
       this.setVisible(true);
   }

/*main主程式執行*/

   public static void main(String[] args){
       painter pp = new painter();
   }

   /*Override*/
   public void update(Graphics g){
       paint(g);
   }
   public void paint(Graphics g){
       /*cr = new Color(fun.Rand(0,255),fun.Rand(0,255),fun.Rand(0,255));*/

/*左右鍵判斷*/
if(mbt==MouseEvent.BUTTON1){g.setColor(cr);}
else if(mbt==MouseEvent.BUTTON3){g.setColor(wht);}

/*模式判斷*/
       if(mode==0){g.fillRect(mx1, my1, mx2-mx1, my2-my1);}
       else if(mode==1){g.drawLine(mx1, my1, mx2, my2);mx1=mx2;my1=my2;}
       else if(mode==-1){g.fillOval(mx-3, my-3, 7, 7);}

       if(clr==true){
           g.setColor(wht);
           g.fillRect(0,0,99999,99999);
           clr=false;
       }

       if(rb==true){
           cr = new Color(fun.Rand(0,255),fun.Rand(0,255),fun.Rand(0,255));
           g.setColor(cr);
       }
   }

   /*-WindowListener interface of event-*/
   @Override
   public void windowOpened(WindowEvent e) {}
   @Override
   public void windowClosing(WindowEvent e) {dispose();}
   @Override
   public void windowClosed(WindowEvent e) {}
   @Override
   public void windowIconified(WindowEvent e) {}
   @Override
   public void windowDeiconified(WindowEvent e) {}
   @Override
   public void windowActivated(WindowEvent e) {}
   @Override
   public void windowDeactivated(WindowEvent e) {}

   /*-mouse motion interface of event-*/
   @Override/*拖曳：mode=-1表示畫點、0與1表示畫線段及方塊*/
   public void mouseDragged(MouseEvent e) {
       if(mode==-1){mx=e.getX();my=e.getY();repaint();}
       else if(mode==0||mode==1){mx2=e.getX();my2=e.getY();repaint();}
       }
   @Override
   public void mouseMoved(MouseEvent e) {}

   /*-Mouse Listener interface of event-*/
   @Override
   public void mouseClicked(MouseEvent e) {}
   @Override/*點擊*/
   public void mousePressed(MouseEvent e) {
       mbt = e.getButton();/*check mouse right, middle, left*/
       if(mode==-1){mx=e.getX();my=e.getY();repaint();}
       else if(mode==0||mode==1){mx1=e.getX();my1=e.getY();}
       }
   @Override
   public void mouseReleased(MouseEvent e) {}
   @Override
   public void mouseEntered(MouseEvent e) {}
   @Override
   public void mouseExited(MouseEvent e) {}

   /*-Action interface of event-*/
   @Override/*判斷按鈕被點擊*/
   public void actionPerformed(ActionEvent e) {
       if(e.getSource()==bt){
           mode++;
           if(mode>1){mode=-1;}
           if(mode==0){bt.setLabel("Rect mode");}
           else if(mode==1){bt.setLabel("Line mode");}
           else if(mode==-1){bt.setLabel("Dot mode");}
       }

       if(e.getSource()==bt2){
           if(clr==false){clr = true;repaint();}
       }

       if(e.getSource()==bt3){
           if(rb==false){rb = true;}
       }

       if(e.getSource()==bt4){
           int r = Integer.parseInt(th_r.getText());
           int g = Integer.parseInt(th_g.getText());
           int b = Integer.parseInt(th_b.getText());

           if(rb==true){rb = false;}
           cr = new Color(r,g,b);
       }
   }
}