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关于画图工具的优化

news 2026/8/16 2:33:45

关于画图工具的优化

针对于之前的画图的优化有以下几点

1曲线的增加
2 对于橡皮擦的优化
3 关于粗细的调整
4对于移动窗体画图的消失

1曲线的增加

主要用到了新的监听器MouseMotionListener
他有俩个方法分别为mouseDragged和mouseMove
主要用到了mouseDragged具体如下
1：导入接口
2：实现方法
3：具体代码（在

x4=e.getX();
y4=e.getY();
if (“曲线”.equals(name)){
gr.drawLine(x1,y1,x4,y4);

x1=x4; y1=y4;

2对于橡皮擦的优化

与曲线相同
注意（有转画笔后会讲）
g2 = (Graphics2D) gr;
g2.setStroke(new BasicStroke(width));
gr.setColor(color);
上为转画笔
g2.setStroke(new BasicStroke(8));

gr.setColor(Color.white); gr.drawLine(x1,y1,x4,y4); x1=x4; y1=y4;

3 关于粗细的调整

在转画笔后
int width=1;
g2 = (Graphics2D) gr;
g2.setStroke(new BasicStroke(width));
//上面的width后填数来控制粗细

4 对于移动窗体画图的消失

这是本篇的大头
首先再建俩个类
一个继承Jpanel，一个创建对象
思路为通过继承来重画进而解决移动窗体画图的消失
具体代码如下

1：主体（建立窗体,传递数据）

public class drawtooi { public void initUI() { JFrame jf = new JFrame(); jf.setSize(1000, 1000); jf.setTitle("drawtool"); jf.setLocationRelativeTo(null); jf.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE); JPanel northJpanel=new JPanel(); northJpanel.setBackground(Color.blue); Dimension di=new Dimension(); di.setSize(0,50); jf.add(northJpanel,BorderLayout.NORTH); draw1 listener=new draw1(); String []name={"直线","矩形","三角形","多边形","圆","椭圆","等腰三角形","红色","蓝色","粗","细","曲线","橡皮擦"}; for (String s : name) { JButton jbu = new JButton(s); northJpanel.add(jbu); jbu.addActionListener(listener); } MPanel drawPanel=new MPanel();// 这为与之前的不同 drawPanel.setBackground(Color.white); jf.add(drawPanel,BorderLayout.CENTER); jf.setVisible(true); Graphics g = drawPanel.getGraphics(); drawPanel.addMouseListener(listener); drawPanel.addMouseMotionListener(listener); listener.gr = g; drawPanel.shapeArr = listener.shapeArr;// 其次是这传递数据 } public static void main(String[] args) { drawtooi ui = new drawtooi(); ui.initUI(); }

}

2画图工具（先别管shape他就是传数据）

注曲线和橡皮擦都有

public class draw1 implements MouseListener, ActionListener, MouseMotionListener { public Graphics gr; public int x1, y1, x2, y2, x3, y3,x4,y4; private String name; private int clickCount = 0; private boolean triangleReady = false; public Color color=Color.black; public int width=1; public Graphics2D g2; public shapes[] shapeArr = new shapes[10000]; //操作数组的下标 public int index = 0; @Override public void actionPerformed(ActionEvent e) { String str = e.getActionCommand(); if ("红色".equals(str)) { color= Color.RED; } else if ("蓝色".equals(str)) { color= Color.BLUE; } else if ("粗".equals(str)) { width = 5; }else if ("细".equals(str)){ width=1; } else{ //表示点击图形按钮 //获取按钮上的内容 name = e.getActionCommand(); } g2 = (Graphics2D) gr; g2.setStroke(new BasicStroke(width)); gr.setColor(color); } @Override public void mouseClicked(MouseEvent e) { if ("三角形".equals(name)) { if (triangleReady) { clickCount = 0; triangleReady = false; return; } clickCount++; if (clickCount == 1) { x1 = e.getX(); y1 = e.getY(); } if (clickCount == 2) { x2 = e.getX(); y2 = e.getY(); gr.drawLine(x1, y1, x2, y2); // 第一条边 System.out.println("x1=" + x1 + " y1=" + y1); System.out.println("x2=" + x2 + " y2=" + y2); } if (clickCount == 3) { x3 = e.getX(); y3 = e.getY(); triangleReady = true; clickCount = 0; // ---- 补全缺失的两条边 ---- gr.drawLine(x1, y1, x3, y3); gr.drawLine(x2, y2, x3, y3); System.out.println("x1=" + x1 + " y1=" + y1); System.out.println("x2=" + x2 + " y2=" + y2); System.out.println("x3=" + x3 + " y3=" + y3); clickCount = 0; shapes shape = new shapes(); shape.name = name; shape.color=color; shape.Width=width; shape.x1 = x1; shape.y1 = y1; shape.x2 = x2; shape.y2 = y2; shape.x3=x3; shape.y3=y3; shapeArr[index] = shape; index++; } } if ("多边形".equals(name)){ clickCount++; if(clickCount==1){ x1=e.getX(); y1=e.getY(); } if (clickCount==2){ x2=e.getX(); y2=e.getY(); gr.drawLine(x1,y1,x2,y2); shapes shape=new shapes(); shape.name=name; shape.color=color; shape.Width=width; shape.x1=x1;shape.y1=y1; shape.x2=x2;shape.y2=y2; shapeArr[index] = shape; index++; } if (clickCount>=3){ x3=e.getX(); y3=e.getY(); gr.drawLine(x2,y2,x3,y3); shapes shape=new shapes(); shape.name=name; shape.color=color; shape.Width=width; shape.x1=x2;shape.y1=y2; shape.x2=x3;shape.y2=y3; shapeArr[index] = shape; index++; x2=x3; y2=y3; if (e.getClickCount()==2){ shapes closeshape=new shapes(); closeshape.name=name; closeshape.color=color; closeshape.Width=width; closeshape.x1=x1;closeshape.y1=y1; closeshape.x2=x3;closeshape.y2=y3; shapeArr[index]=closeshape; index++; gr.drawLine(x1,y1,x3,y3); clickCount=0; } } } } @Override public void mousePressed(MouseEvent e) { if ("三角形".equals(name)) { return; } if ("多边形".equals(name)) { return; } x1 = e.getX(); y1 = e.getY(); } @Override public void mouseReleased(MouseEvent e) { if ("多边形".equals(name)) { return; } if ("三角形".equals(name)) { return; } x2 = e.getX(); y2 = e.getY(); //绝对值 int w = Math.abs(x2 - x1); int q = Math.abs(y2 - y1); //取最小值 int mx = Math.min(x1, x2); int my = Math.min(y1, y2); int top = (x1 + x2) / 2; if ("直线".equals(name)) { gr.drawLine(x1, y1, x2, y2); shapes shape = new shapes(); shape.name = name; shape.color=color; shape.Width=width; shape.x1 = x1; shape.y1 = y1; shape.x2 = x2; shape.y2 = y2; shapeArr[index] = shape; index++; } if ("矩形".equals(name)) { gr.drawRect(mx, my, w, q); shapes shape = new shapes(); shape.name = name; shape.color=color; shape.Width=width; shape.x1 = x1; shape.y1 = y1; shape.x2 = x2; shape.y2 = y2; shapeArr[index] = shape; index++; } if ("等腰三角形".equals(name)) { gr.drawLine(top, y1, x2, y2); gr.drawLine(x1, y2, x2, y2); gr.drawLine(top, y1, x1, y2); shapes shape=new shapes(); shape.name = name; shape.color=color; shape.Width=width; shape.x1 = x1; shape.y1 = y1; shape.x2 = x2; shape.y2 = y2; shapeArr[index] = shape; index++; } if ("圆".equals(name)){ gr.drawOval(x1,y1,w,w); shapes shape=new shapes(); shape.name = name; shape.color=color; shape.Width=width; shape.x1 = x1; shape.y1 = y1; shape.x2 = x2; shape.y2 = y2; shapeArr[index] = shape; index++; } if ("椭圆".equals(name)){ gr.drawOval(x1,y1,w,q); shapes shape=new shapes(); shape.name = name; shape.color=color; shape.Width=width; shape.x1 = x1; shape.y1 = y1; shape.x2 = x2; shape.y2 = y2; shapeArr[index] = shape; index++; } } @Override public void mouseEntered(MouseEvent e) { } @Override public void mouseExited(MouseEvent e) { } @Override public void mouseDragged(MouseEvent e) { x4=e.getX(); y4=e.getY(); if ("曲线".equals(name)){ gr.drawLine(x1,y1,x4,y4); shapes shape=new shapes(); shape.name = name; shape.color=color; shape.Width=width; shape.x1 = x1; shape.y1 = y1; shape.x2 = x4; shape.y2 = y4; shapeArr[index] = shape; index++; x1=x4; y1=y4; } if ("橡皮擦".equals(name)){ g2.setStroke(new BasicStroke(8)); gr.setColor(Color.white); gr.drawLine(x1,y1,x4,y4); shapes shape=new shapes(); shape.name = name; shape.color=color; shape.Width=8; shape.x1 = x1; shape.y1 = y1; shape.x2 = x4; shape.y2 = y4; shapeArr[index] = shape; index++; x1=x4; y1=y4; } } @Override public void mouseMoved(MouseEvent e) {

}
}

3继承（重中之重）在之前提过super

public class MPanel extends JPanel {
public shapes[] shapeArr; //保存图形的数组

//重写paint方法 public void paint(Graphics g) { //保留绘制组件的功能 super.paint(g); System.out.println("paint..."); //取出所有的图形对象，实现重绘 for (shapes shapes : shapeArr) { if (shapes == null) continue; shapes.drawshape(g); } }

}

4重画

public class shapes {

public int x1,y1,x2,y2,x3,y3; public int Width; public Color color=Color.black; public String name; public void drawshape(Graphics g){ if (g==null)return; Graphics2D g2d=(Graphics2D) g; g2d.setColor(this.color); g2d.setStroke(new BasicStroke(Width)); if (name !=null) { switch (name) { case "直线": g2d.drawLine(x1, y1, x2, y2); break; case "矩形": int x = Math.min(x1, x2); int y = Math.min(y1, y2); int w = Math.abs(x1 - x2); int h = Math.abs(y2 - y1); g2d.drawRect(x, y, w, h); break; case "等腰三角形": int top = (x1 + x2) / 2; g2d.drawLine(top, y1, x2, y2); g2d.drawLine(x1, y2, x2, y2); g2d.drawLine(top, y1, x1, y2); break; case "圆": int m = Math.abs(x1 - x2); g2d.drawOval(x1, y1, m, m); case "椭圆": int width = Math.abs(x1 - x2); int height = Math.abs(y1 - y2); g2d.drawOval(x1, y2, width, height); case "三角形": g2d.drawLine(x1, y1, x2, y2); g2d.drawLine(x1, y1, x3, y3); g2d.drawLine(x3, y3, x2, y2); break; case "多边形": g2d.drawLine(x1,y1,x2,y2); break; case "曲线": g2d.drawLine(x1,y1,x2,y2); break; case "橡皮擦": g2d.setColor(Color.white); g2d.drawLine(x1,y1,x2,y2); } } }

}

5讲解

1：shape为一个数组来计录画图的点与按键的名称画图的粗细与颜色
来实现重画
2：继承了Jpanel的方法（用了super）加了一个方法通过数组来计录方便重画
3：4中的case与if相同及""中的相同就运行：后的，再运行后要加break停止运行
4：在多边形的重画中建了一个新数组来计录一开始的点避免找不到一开始的点，就可以闭合
5：在曲线与橡皮擦的重画可以看成无数个线段连成在画是一样（在画时与多边形相同不断更新来实现不断画）

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