Java实现简易画图板
最近自己尝试学着实现了一个简单的画图板，可以画出直线、圆、曲线、喷枪、直角矩形、圆角矩形等图形，而且可以通过橡皮擦擦除。欢迎各位大佬提出建议。
DrawMain.java
主类用于创建画板对象，添加所需的组件。
public void init_ui(){/*界面初始化*/JFrame jf=new JFrame();jf.setSize(1000,700);jf.setTitle("画图板");jf.setDefaultCloseOperation(3); //设置窗口相对于指定组件的位置，此窗口将置于屏幕的中央。jf.setLocationRelativeTo(null);jf.setLayout(new BorderLayout());//设置布局//实例化事件监听类DrawListener dl=new DrawListener(this);//设置中间面板，背景颜色为白色this.setBackground(Color.WHITE);jf.add(this,BorderLayout.CENTER);//实现性状面板JPanel ShapePanel=new JPanel();ShapePanel.setBackground(Color.black);ShapePanel.setLayout(new FlowLayout(FlowLayout.CENTER));ShapePanel.setBackground(Color.gray);//shape字符串数组的每个元素表示一种形状名称String [] shape={"直线","曲线","圆","喷枪","橡皮擦","矩形","椭圆","圆角矩形","弧线","多边形","图形","三角形","立体圆",};for(int i=0;i<shape.length;i++){//创建各个形状的按钮JButton button=new JButton(shape[i]);button.setBackground(Color.WHITE);button.addActionListener(dl); //添加事件监听机制ShapePanel.add(button);}jf.add(ShapePanel,BorderLayout.NORTH);//实现调色板JPanel ColorPanel=new JPanel();ColorPanel.setBackground(Color.black);ColorPanel.setLayout(new FlowLayout(FlowLayout.CENTER));ColorPanel.setBackground(Color.gray);//shape数组的每个元素表示一种颜色Color [] color={Color.BLACK,Color.blue,Color.yellow,Color.red,Color.CYAN,Color.green,Color.darkGray,Color.pink};for(int i=0;i<color.length;i++){//创建控制颜色的按钮JButton button=new JButton();button.addActionListener(dl); //添加事件监听机制button.setPreferredSize(new Dimension(30,30));button.setBackground(color[i]);ColorPanel.add(button);}jf.add(ColorPanel,BorderLayout.SOUTH);jf.setVisible(true);//添加事件监听，通过鼠标实现作图this.addMouseListener(dl);this.addMouseMotionListener(dl);}
事件监听类用于实现画图、更改颜色和擦除等功能，其中主要的代码如下。
//获取形状和颜色public void actionPerformed(ActionEvent e){if(e.getActionCommand().equals("")){JButton button = (JButton) e.getSource(); color = button.getBackground(); }else{JButton button = (JButton) e.getSource(); shape = button.getActionCommand(); }}
画笔的实现。
public void mousePressed(MouseEvent e) {g=(Graphics2D) df.getGraphics();g.setColor(color);x1=e.getX();y1=e.getY();}
public void mouseReleased(MouseEvent e) {x2 = e.getX();y2 = e.getY();if (shape.equals("直线")) {g.drawLine(x1, y1, x2, y2);}else if(shape.equals("弧线")){g.drawArc(x1, y1, Math.abs(x2-x1), Math.abs(y2-y1), 0, 180);}else if(shape.equals("多边形")&&!flag){g.drawLine(x1, y1, x2, y2);newx1=x1;newy1=y1;newx2=x2;newy2=y2;flag=true;}else if(shape.equals("圆")){g.drawOval(x1, y1, Math.abs(x2-x1), Math.abs(y2-y1));}else if(shape.equals("矩形")){g.drawRect(x1, y1, Math.abs(x2-x1), Math.abs(y2-y1));}else if(shape.equals("圆角矩形")){g.drawRoundRect(x1, y1, Math.abs(x2-x1), Math.abs(y2-y1),2,10);}else if(shape.equals("椭圆")){g.drawOval(x1, y1, Math.abs(x2-x1), Math.abs(y2-y1));}}
public void mouseClicked(MouseEvent e) {if(shape.equals("多边形")&&flag){x2=e.getX();y2=e.getY();if(e.getClickCount()==2){g.drawLine(newx1, newy1, newx2, newy2);flag=false;}g.drawLine(newx2, newy2, x2, y2);newx2=x2;newy2=y2;}else if(shape.equals("图形")){arrx[temp]=e.getX();arry[temp]=e.getY();temp++;if(temp==4){int x=arrx[3];int y=arry[3];for(int i=0;i<=10000;i++){Random ran=new Random();int k=ran.nextInt(3);x=(x+arrx[k])/2;y=(y+arry[k])/2;g.drawLine(x, y, x, y);}temp=0;}}else if(shape.equals("立体圆")){double a=1.40,b=1.56,c=1.40,d=-6.56;double x = 0,xo=0;double y = 0,yo=0;Color [] Col={Color.BLUE,Color.cyan,Color.green,Color.magenta,Color.red,Color.yellow};for(int i=0;i<=90000;i++){Random r=new Random();//增加颜色int R=r.nextInt(Col.length);g.setColor(Col[R]);x=d*Math.sin(a*xo)-Math.sin(b*yo);y=c*Math.cos(a*xo)+Math.cos(b*yo);int temp_x=(int)(x*50);int temp_y=(int)(y*50);g.drawLine(temp_x+500, temp_y+300, temp_x+500, temp_y+300);xo=x;yo=y;} }else if(shape.equals("三角形")){double a=-2,b=-2,c=-1.2,d=2;double x = 0,xo=0;double y = 0,yo=0;Color [] Col={Color.BLUE,Color.cyan,Color.green,Color.magenta,Color.red,Color.yellow};for(int i=0;i<=90000;i++){Random r=new Random();//增加颜色int R=r.nextInt(Col.length);g.setColor(Col[R]); x=Math.sin(a*yo)-Math.cos(b*xo);y=Math.sin(c*xo)-Math.cos(d*yo);int temp_x=(int)(x*50);int temp_y=(int)(y*50); g.drawLine(temp_x+500, temp_y+300, temp_x+500, temp_y+300);xo=x;yo=y;}}}
public void mouseDragged(MouseEvent e) {x2 = e.getX();y2 = e.getY();if (shape.equals("曲线")) {g.drawLine(x1, y1, x2, y2);x1 = x2;y1 = y2;}else if(shape.equals("橡皮擦")){g.setStroke(new BasicStroke(80));g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);g.setColor(Color.WHITE);g.drawLine(x1, y1, x2, y2);x1 = x2;y1 = y2;}else if(shape.equals("喷枪")){for(int k=0;k<20;k++){Random i=new Random(); int a=i.nextInt(8);int b=i.nextInt(10);g.drawLine(x2+a, y2+b, x2+a, y2+b);}}}
运行效果如下
初始面板
画画ing
源码下载-Java实现简易画图板
参考博主地址
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