Java实现的图像查看器完整实例

Java实现的图像查看器完整实例

本文实例讲述了java实现的图像查看器。分享给大家供大家参考。具体如下：

1. MyCanvas.java：

package PictureViewer;

import java.awt.*;

import java.awt.event.*;

impCXgbfYszBwort java.awt.image.*;

public class MyCanvas extends Canvas implements ComponentListener{

private BufferedImage bi;

private Image im;

private int image_width;

private int image_height;

public void setImage(BufferedImage bi){

this.bi = bi;

this.zoom();

}

public void paint(Graphics g){

g.drawImage(im,(this.getWidth()-image_width)/2,(this.getHeight()-image_height)/2,this);

}

public void componentResized(ComponentEvent e){

if(bi != null){

System.out.println("resize!!");

this.zoom();

this.repaint();

}

}

public void componentMoved(ComponentEvent e){}

public void componentShown(ComponentEvent e){}

public void componentHidden(ComponentEvent e){}

public void zoom(){

if(bi == null)

return;

int screen_width = this.getWidth();

int screen_height = this.getHeight();

double screen_proportion = 1.0 * screen_height / screen_width;

System.out.println("screen: w "+screen_width+" ,h "+screen_height+" ,p0 "+screen_proportion);

image_width = bi.getWidth(this);

image_height = bi.getHeight(this);

double image_proportion = 1.0 * image_height / image_width;

System.out.println("image: w "+image_width+" ,h "+image_height+" ,p1 "+image_proportion);

if(image_proportion > screen_proportion){

image_height = screen_height;

image_width = (int)(image_height / image_proportion);

System.out.println(" p1>p0 w= "+image_width);

}else{

image_width = screen_width;

image_height = (int)(image_width * image_proportion);

System.out.println(" p0>p1 h= "+image_height);

}

im = bi.getScaledInstance(image_width,image_height,Image.SCALE_SMOOTH);

}

}

2. MyFilter.java：

package PictureViewer;

import java.io.File;

import java.io.FilenameFilter;

public class MyFilter implements FilenameFilter{

private String[] extension;

public MyFilter(){

extension = new String[]{".jpg", ".JPG", ".gif", ".GIF", ".png", ".PNG", ".jpeg", ".JPEG"};

}

public MyFilter(String[] extension){

this.extension = extension;

}

public boolean accept(File dir,String name){

for(String s : extension){

if(name.endsWith(s)){

return true;

}

}

return false;

}

}

3. PictureViewer.java：

package PictureViewer;

import java.awt.*;

import java.awt.event.*;

import java.awt.image.*;

import java.io.*;

import javax.imageio.*;

public class PictureViewer implements ActionListener{

private Frame frame;

private MyCanvas mc ;

private String fpath;

private String fname;

private File[] files;

private int findex ;

private FileDialog fd_load;

private MyFilter filter;

private Button previous ;

private Button next ;

public static void main( String args[]) throws Exception {

new PictureViewer().init();

}

public void init(){

frame = new Frame("PictureViewer");

Panel pb = new Panel();

Button select = new Button("选择图片");

previous = new Button("上一张");

next = new Button("下一张");

select.addActionListener(this);

previous.addActionListener(this);

next.addActionListener(this);

pb.add(select);

pb.add(previous);

pb.add(next);

mc = new MyCanvas();

mc.setBackground(new Color(200,210,230));

mc.addComponentListener(mc);

frame.add(pb,"North");

frame.add(mc,"Center");

frame.setSize(360,360);

frame.setLocation(400,200);

frame.addWindowListener(new WindowAdapter(){

public void windowClosing(WindowEvent e){

System.exit(0);

}

});

frame.setVisible(true);

this.validateButton();

filter = new MyFilter();

fd_load = new FileDialog(frame,"打开文件",FileDialog.LOAD);

fd_load.setFilenameFilter(filter);

}

public void actionPerformed(ActionEvent e){

String command = e.getActionCommand();

if(command.equals("选择图片")){

fd_load.setVisible(true);

fpath = fd_load.getDirectory();

fname = fd_load.getFile();

if((fpath != null) && (fname != null)){

this.display(new File(fpath + fname));

files = new File(fpath).listFiles(filter);

this.setIndex();

}

}else if(command.equals("上一张")){

findex--;

if(findex<0)

findex = 0;

this.display(files[findex]);

}else if(command.equals("下一张")){

findex++;

if(findex >= files.length)

findex = files.length-1;

this.display(files[findex]);

}

this.validateButton();

}

public void display(File f){

try{

BufferedImage bi = ImageIO.read(f);

mc.setImage(bi);

frame.setTitle("PictureViewer - [" + f.getName() + "]");

}catch(Exception e){

e.printStackTrace();

}

mc.repaint();

}

public void setIndex(){

File current = new File(fpath + fname);

if(files != null){

for(int i=0;i

if(current.equals(files[i])){

findex = i;

}

}

}

}

public void validateButton(){

previous.setEnabled((files!=null) && (findex > 0));

next.setEnabled((files!=null) && (findex<(files.length-1)));

}

}

希望本文所述对大家的java程序设计有所帮助。

if(current.equals(files[i])){

findex = i;

}

}

}

}

public void validateButton(){

previous.setEnabled((files!=null) && (findex > 0));

next.setEnabled((files!=null) && (findex<(files.length-1)));

}

}

希望本文所述对大家的java程序设计有所帮助。

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