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java 实现 简单画图功能(简单点的)

英文信件 • 2023-5-19 • IT百科 • 阅读 11

java 实现 简单画图功能(简单点的),第1张

楼主给你一个我编的，直接保存成pb.java编译运行，就是你要的画图功能

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import java.applet.*

import java.awt.*

import java.awt.event.*

import java.util.*

import javax.swing.*

import java.awt.geom.*

import java.io.*

class Point implements Serializable

{

int x,y

Color col

int tool

int boarder

Point(int x, int y, Color col, int tool, int boarder)

{

this.x = x

this.y = y

this.col = col

this.tool = tool

this.boarder = boarder

}

}

class paintboard extends Frame implements ActionListener,MouseMotionListener,MouseListener,ItemListener

{

int x = -1, y = -1

int con = 1//画笔大小

int Econ = 5//橡皮大小

int toolFlag = 0//toolFlag:工具标记

//toolFlag工具对应表：

//（0--画笔）；（1--橡皮）；（2--清除）；

//（3--直线）；（4--圆）；（5--矩形）；

Color c = new Color(0,0,0)//画笔颜色

BasicStroke size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL)//画笔粗细

Point cutflag = new Point(-1, -1, c, 6, con)//截断标志

Vector paintInfo = null//点信息向量组

int n = 1

FileInputStream picIn = null

FileOutputStream picOut = null

ObjectInputStream VIn = null

ObjectOutputStream VOut = null

// *工具面板--画笔，直线，圆，矩形，多边形,橡皮，清除*/

Panel toolPanel

Button eraser, drLine,drCircle,drRect

Button clear ,pen

Choice ColChoice,SizeChoice,EraserChoice

Button colchooser

Label 颜色,大小B,大小E

//保存功能

Button openPic,savePic

FileDialog openPicture,savePicture

paintboard(String s)

{

super(s)

addMouseMotionListener(this)

addMouseListener(this)

paintInfo = new Vector()

/*各工具按钮及选择项*/

//颜色选择

ColChoice = new Choice()

ColChoice.add("black")

ColChoice.add("red")

ColChoice.add("blue")

ColChoice.add("green")

ColChoice.addItemListener(this)

//画笔大小选择

SizeChoice = new Choice()

SizeChoice.add("1")

SizeChoice.add("3")

SizeChoice.add("5")

SizeChoice.add("7")

SizeChoice.add("9")

SizeChoice.addItemListener(this)

//橡皮大小选择

EraserChoice = new Choice()

EraserChoice.add("5")

EraserChoice.add("9")

EraserChoice.add("13")

EraserChoice.add("17")

EraserChoice.addItemListener(this)

////////////////////////////////////////////////////

toolPanel = new Panel()

clear = new Button("清除")

eraser = new Button("橡皮")

pen = new Button("画笔")

drLine = new Button("画直线")

drCircle = new Button("画圆形")

drRect = new Button("画矩形")

openPic = new Button("打开图画")

savePic = new Button("保存图画")

colchooser = new Button("显示调色板")

//各组件事件监听

clear.addActionListener(this)

eraser.addActionListener(this)

pen.addActionListener(this)

drLine.addActionListener(this)

drCircle.addActionListener(this)

drRect.addActionListener(this)

openPic.addActionListener(this)

savePic.addActionListener(this)

colchooser.addActionListener(this)

颜色 = new Label("画笔颜色",Label.CENTER)

大小B = new Label("画笔大小",Label.CENTER)

大小E = new Label("橡皮大小",Label.CENTER)

//面板添加组件

toolPanel.add(openPic)

toolPanel.add(savePic)

toolPanel.add(pen)

toolPanel.add(drLine)

toolPanel.add(drCircle)

toolPanel.add(drRect)

toolPanel.add(颜色)toolPanel.add(ColChoice)

toolPanel.add(大小B)toolPanel.add(SizeChoice)

toolPanel.add(colchooser)

toolPanel.add(eraser)

toolPanel.add(大小E)toolPanel.add(EraserChoice)

toolPanel.add(clear)

//工具面板到APPLET面板

add(toolPanel,BorderLayout.NORTH)

setBounds(60,60,900,600)setVisible(true)

validate()

//dialog for save and load

openPicture = new FileDialog(this,"打开图画",FileDialog.LOAD)

openPicture.setVisible(false)

savePicture = new FileDialog(this,"保存图画",FileDialog.SAVE)

savePicture.setVisible(false)

openPicture.addWindowListener(new WindowAdapter()

{

public void windowClosing(WindowEvent e)

{ openPicture.setVisible(false)}

})

savePicture.addWindowListener(new WindowAdapter()

{

public void windowClosing(WindowEvent e)

{ savePicture.setVisible(false)}

})

addWindowListener(new WindowAdapter()

{

public void windowClosing(WindowEvent e)

{ System.exit(0)}

})

}

public void paint(Graphics g)

{

Graphics2D g2d = (Graphics2D)g

Point p1,p2

n = paintInfo.size()

if(toolFlag==2)

g.clearRect(0,0,getSize().width,getSize().height)//清除

for(int i=0i<n i++){

p1 = (Point)paintInfo.elementAt(i)

p2 = (Point)paintInfo.elementAt(i+1)

size = new BasicStroke(p1.boarder,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL)

g2d.setColor(p1.col)

g2d.setStroke(size)

if(p1.tool==p2.tool)

{

switch(p1.tool)

{

case 0://画笔

Line2D line1 = new Line2D.Double(p1.x, p1.y, p2.x, p2.y)

g2d.draw(line1)

break

case 1://橡皮

g.clearRect(p1.x, p1.y, p1.boarder, p1.boarder)

break

case 3://画直线

Line2D line2 = new Line2D.Double(p1.x, p1.y, p2.x, p2.y)

g2d.draw(line2)

break

case 4://画圆

Ellipse2D ellipse = new Ellipse2D.Double(p1.x, p1.y, Math.abs(p2.x-p1.x) , Math.abs(p2.y-p1.y))

g2d.draw(ellipse)

break

case 5://画矩形

Rectangle2D rect = new Rectangle2D.Double(p1.x, p1.y, Math.abs(p2.x-p1.x) , Math.abs(p2.y-p1.y))

g2d.draw(rect)

break

case 6://截断，跳过

i=i+1

break

default :

}//end switch

}//end if

}//end for

}

public void itemStateChanged(ItemEvent e)

{

if(e.getSource()==ColChoice)//预选颜色

{

String name = ColChoice.getSelectedItem()

if(name=="black")

{c = new Color(0,0,0)}

else if(name=="red")

{c = new Color(255,0,0)}

else if(name=="green")

{c = new Color(0,255,0)}

else if(name=="blue")

{c = new Color(0,0,255)}

}

else if(e.getSource()==SizeChoice)//画笔大小

{

String selected = SizeChoice.getSelectedItem()

if(selected=="1")

{

con = 1

size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL)

}

else if(selected=="3")

{

con = 3

size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL)

}

else if(selected=="5")

{con = 5

size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL)

}

else if(selected=="7")

{con = 7

size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL)

}

else if(selected=="9")

{con = 9

size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL)

}

}

else if(e.getSource()==EraserChoice)//橡皮大小

{

String Esize = EraserChoice.getSelectedItem()

if(Esize=="5")

{ Econ = 5*2}

else if(Esize=="9")

{ Econ = 9*2}

else if(Esize=="13")

{ Econ = 13*2}

else if(Esize=="17")

{ Econ = 17*3}

}

}

public void mouseDragged(MouseEvent e)

{

Point p1

switch(toolFlag){

case 0://画笔

x = (int)e.getX()

y = (int)e.getY()

p1 = new Point(x, y, c, toolFlag, con)

paintInfo.addElement(p1)

repaint()

break

case 1://橡皮

x = (int)e.getX()

y = (int)e.getY()

p1 = new Point(x, y, null, toolFlag, Econ)

paintInfo.addElement(p1)

repaint()

break

default :

}

}

public void mouseMoved(MouseEvent e) {}

public void update(Graphics g)

{

paint(g)

}

public void mousePressed(MouseEvent e)

{

Point p2

switch(toolFlag){

case 3://直线

x = (int)e.getX()

y = (int)e.getY()

p2 = new Point(x, y, c, toolFlag, con)

paintInfo.addElement(p2)

break

case 4: //圆

x = (int)e.getX()

y = (int)e.getY()

p2 = new Point(x, y, c, toolFlag, con)

paintInfo.addElement(p2)

break

case 5: //矩形

x = (int)e.getX()

y = (int)e.getY()

p2 = new Point(x, y, c, toolFlag, con)

paintInfo.addElement(p2)

break

default :

}

}

public void mouseReleased(MouseEvent e)

{

Point p3

switch(toolFlag){

case 0://画笔

paintInfo.addElement(cutflag)

break

case 1: //eraser

paintInfo.addElement(cutflag)

break

case 3://直线

x = (int)e.getX()

y = (int)e.getY()

p3 = new Point(x, y, c, toolFlag, con)

paintInfo.addElement(p3)

paintInfo.addElement(cutflag)

repaint()

break

case 4: //圆

x = (int)e.getX()

y = (int)e.getY()

p3 = new Point(x, y, c, toolFlag, con)

paintInfo.addElement(p3)

paintInfo.addElement(cutflag)

repaint()

break

case 5: //矩形

x = (int)e.getX()

y = (int)e.getY()

p3 = new Point(x, y, c, toolFlag, con)

paintInfo.addElement(p3)

paintInfo.addElement(cutflag)

repaint()

break

default:

}

}

public void mouseEntered(MouseEvent e){}

public void mouseExited(MouseEvent e){}

public void mouseClicked(MouseEvent e){}

public void actionPerformed(ActionEvent e)

{

if(e.getSource()==pen)//画笔

{toolFlag = 0}

if(e.getSource()==eraser)//橡皮

{toolFlag = 1}

if(e.getSource()==clear)//清除

{

toolFlag = 2

paintInfo.removeAllElements()

repaint()

}

if(e.getSource()==drLine)//画线

{toolFlag = 3}

if(e.getSource()==drCircle)//画圆

{toolFlag = 4}

if(e.getSource()==drRect)//画矩形

{toolFlag = 5}

if(e.getSource()==colchooser)//调色板

{

Color newColor = JColorChooser.showDialog(this,"调色板",c)

c = newColor

}

if(e.getSource()==openPic)//打开图画

{

openPicture.setVisible(true)

if(openPicture.getFile()!=null)

{

int tempflag

tempflag = toolFlag

toolFlag = 2

repaint()

try{

paintInfo.removeAllElements()

File filein = new File(openPicture.getDirectory(),openPicture.getFile())

picIn = new FileInputStream(filein)

VIn = new ObjectInputStream(picIn)

paintInfo = (Vector)VIn.readObject()

VIn.close()

repaint()

toolFlag = tempflag

}

catch(ClassNotFoundException IOe2)

{

repaint()

toolFlag = tempflag

System.out.println("can not read object")

}

catch(IOException IOe)

{

repaint()

toolFlag = tempflag

System.out.println("can not read file")

}

}

}

if(e.getSource()==savePic)//保存图画

{

savePicture.setVisible(true)

try{

File fileout = new File(savePicture.getDirectory(),savePicture.getFile())

picOut = new FileOutputStream(fileout)

VOut = new ObjectOutputStream(picOut)

VOut.writeObject(paintInfo)

VOut.close()

}

catch(IOException IOe)

{

System.out.println("can not write object")

}

}

}

}//end paintboard

public class pb

{

public static void main(String args[])

{ new paintboard("画图程序")}

}

只提指导，没有源码。

在 Java 中要自定义组件，一般是覆盖掉 protected void paintComponent(Graphics g)方法就可以了，对于你这个类似画笔的程序，首先，整个画布是一个自定义的继承自像 JPanel 一样的东西，不过我们需要覆盖它的 paintComponent 方法，因为：一、我们需要在当鼠标拖放一个东西时我们移动这个选中的图形时记住它的位置；二、设定 label 时需要保存它的 Label。三、知道图形的形状。

,然后在 paintComponent 时依次画出各个图形来。

要绘图：

1、直线，g.drawLine(x,y,x2,y2)// 参数分别是起止点坐标。

2、矩形，g.fillRect(x, y, w, h)// 参数分别是左上角坐标和宽及高。

3、椭圆，g.fillOval(x, y, w, h)// 参数分别是椭圆形的外切矩形的左上角坐标及宽和高，当w 和 h 相等时是个圆。

准备绘图前 g.setColor() 设置前景色；先把整个画布用 g.fillRect() 涂成白色，再分别画各个图形，最后绘制 Label 应该在画图形之后再做。

移动图形，是给 画布组件 addMouseMotionListener 来监听事件的，在拖动时先通过 mouseDragged 事件的 MouseEvent.point 知道它的位置是在哪个图形的内部，之后的移动就修改这个图形的位置。

欢迎分享，转载请注明来源：内存溢出

原文地址: http://outofmemory.cn/bake/11909210.html

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