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[转载]用Swing处理图片缩放和拖动

原创 Linux操作系统 作者:dinner1007 时间:2019-04-19 16:18:07 0 删除 编辑
用Swing处理图片缩放和拖动

最近在研究applet怎么处理图片缩放,现简单做了一个例子,与大家分享!

package applet;

import java.awt.Color;
import java.awt.Cursor;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;

import javax.swing.ImageIcon;
import javax.swing.JApplet;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.border.LineBorder;

public class ImageApplet extends JApplet {

private JPanel jContentPane = null;

private JPanel jPanel = null;

ImageIcon imageIcon = new ImageIcon("images/icon/common/det_dis.gif");

/**
* This is the default constructor
*/
public ImageApplet() {
super();
}

/**
* This method initializes this
*
* @return void
*/
public void init() {
this.setSize(640, 480);
this.setContentPane(getJContentPane());
}

/**
* This method initializes jContentPane
*
* @return javax.swing.JPanel
*/
private JPanel getJContentPane() {
if (jContentPane == null) {
jContentPane = new JPanel();
jContentPane.setLayout(null);
jContentPane.add(new MainPanel(imageIcon), null);
}
return jContentPane;
}

/**
* This method initializes jPanel
*
* @return javax.swing.JPanel
*/
class MainPanel extends JPanel implements MouseListener,
MouseMotionListener {
int x1, y1;
//用来表示向东、南、西、北、东、南、东、北、西南、西北八个方向缩放点
private JLabel northWest = null;

private JLabel north = null;

private JLabel northEast = null;

private JLabel east = null;

private JLabel southEast = null;

private JLabel south = null;

private JLabel southWest = null;

private JLabel west = null;
//图片
ImageIcon imageIcon = null;
//是否可缩放标记
boolean isSelected = false;

public MainPanel(ImageIcon imageIcon) {
this.imageIcon = imageIcon;
this.setBounds(256,107,40,30);
x1 = this.getWidth();
y1 = this.getHeight();
//初始化东、南、西、北、东、南、东、北、西南、西北八个方向缩放点
northWest = new JLabel();
northWest.setText("");
northWest.setBorder(new LineBorder(Color.WHITE, 1));
northWest.addMouseListener(this);
northWest.addMouseMotionListener(this);
northWest.setVisible(false);

north = new JLabel();
north.setText("");
north.setBorder(new LineBorder(Color.WHITE, 1));
north.addMouseListener(this);
north.addMouseMotionListener(this);
north.setVisible(false);

northEast = new JLabel();
northEast.setText("");
northEast.setBorder(new LineBorder(Color.WHITE, 1));
northEast.addMouseListener(this);
northEast.addMouseMotionListener(this);
northEast.setVisible(false);

east = new JLabel();
east.setText("");
east.setBorder(new LineBorder(Color.WHITE, 1));
east.addMouseListener(this);
east.addMouseMotionListener(this);
east.setVisible(false);

southEast = new JLabel();
southEast.setText("");
southEast.setBorder(new LineBorder(Color.WHITE, 1));
southEast.addMouseListener(this);
southEast.addMouseMotionListener(this);
southEast.setVisible(false);

south = new JLabel();
south.setText("");
south.setBorder(new LineBorder(Color.WHITE, 1));
south.addMouseListener(this);
south.addMouseMotionListener(this);
south.setVisible(false);

southWest = new JLabel();
southWest.setText("");
southWest.setBorder(new LineBorder(Color.WHITE, 1));
southWest.addMouseListener(this);
southWest.addMouseMotionListener(this);
southWest.setVisible(false);

west = new JLabel();
west.setText("");
west.setBorder(new LineBorder(Color.WHITE, 1));
west.addMouseListener(this);
west.addMouseMotionListener(this);
west.setVisible(false);
//东、南、西、北、东、南、东、北、西南、西北八个方向缩放点的坐标
northWest.setBounds(0, 0, 5, 5);
north.setBounds((x1 - 3) / 2, 0, 5, 5);
northEast.setBounds(x1 - 5, 0, 5, 5);
east.setBounds(x1 - 5, (y1 - 3) / 2, 5, 5);
southEast.setBounds(x1 - 5, y1 - 5, 5, 5);
south.setBounds((x1 - 3) / 2, y1 - 5, 5, 5);
southWest.setBounds(0, y1 - 5, 5, 5);
west.setBounds(0, (y1 - 3) / 2, 5, 5);

this.setLayout(null);
this.setMinimumSize(new Dimension(20, 20));
this.addMouseListener(this);
this.addMouseMotionListener(this);
//加入缩放点到jpanel中
this.add(northWest, null);
this.add(north, null);
this.add(northEast, null);
this.add(east, null);
this.add(southEast, null);
this.add(south, null);
this.add(southWest, null);
this.add(west, null);
}
//单击后可以进行缩放处理
public void mouseClicked(MouseEvent e) {
isSelected = true;
this.setBorder(new LineBorder(Color.BLACK, 4));
northWest.setVisible(true);
north.setVisible(true);
northEast.setVisible(true);
east.setVisible(true);
southEast.setVisible(true);
south.setVisible(true);
southWest.setVisible(true);
west.setVisible(true);
this.repaint();
}

public void mousePressed(MouseEvent e) {
// TODO Auto-generated method stub

}
//防止鼠标在缩放时移出了方向点区域,图片的缩放不能进行
public void mouseReleased(MouseEvent e) {
if(isSelected){
if(getCursor().getType()!=Cursor.DEFAULT_CURSOR){
setCursor(new Cursor(Cursor.DEFAULT_CURSOR));
}
}

}
//鼠标进入哪个缩放点区域
public void mouseEntered(MouseEvent e) {
if (isSelected) {
if (e.getComponent() == northWest) {
setCursor(new Cursor(Cursor.NW_RESIZE_CURSOR));
} else if (e.getComponent() == north) {
setCursor(new Cursor(Cursor.N_RESIZE_CURSOR));
} else if (e.getComponent() == northEast) {
setCursor(new Cursor(Cursor.NE_RESIZE_CURSOR));
} else if (e.getComponent() == east) {
setCursor(new Cursor(Cursor.E_RESIZE_CURSOR));
} else if (e.getComponent() == southEast) {
setCursor(new Cursor(Cursor.SE_RESIZE_CURSOR));
} else if (e.getComponent() == south) {
setCursor(new Cursor(Cursor.S_RESIZE_CURSOR));
} else if (e.getComponent() == southWest) {
setCursor(new Cursor(Cursor.SW_RESIZE_CURSOR));
} else if (e.getComponent() == west) {
setCursor(new Cursor(Cursor.W_RESIZE_CURSOR));
} /*else if(e.getComponent() == this){
setCursor(new Cursor(Cursor.DEFAULT_CURSOR));
}*/
}
}

public void mouseExited(MouseEvent e) {
}
//缩放及拖动的操作
public void mouseDragged(MouseEvent e) {
if (isSelected) {
int type = getCursor().getType();
int x, y, w, h;
x = this.getX();
y = this.getY();
w = this.getWidth();
h = this.getHeight();
switch (type) {
case Cursor.NW_RESIZE_CURSOR://西北方向缩放
if(w - e.getX() >20&& h - e.getY()>20){
w = w - e.getX();
h = h - e.getY();
this.setBounds(x + e.getX(), y+ e.getY(), w, h);
}
break;
case Cursor.N_RESIZE_CURSOR://北
if(h-e.getY()>20){
h = h - e.getY();
this.setBounds(x, y + e.getY(),w, h);
}
break;
case Cursor.NE_RESIZE_CURSOR://东北
if(w + e.getX()>20 && h - e.getY()>20){
w = w + e.getX();
h = h - e.getY();
this.setBounds(x, y + e.getY(),w, h);
}
break;
case Cursor.E_RESIZE_CURSOR://东
if(w + e.getX()>20){
w = w + e.getX();
this.setBounds(x, y, w, h);
}
break;
case Cursor.SE_RESIZE_CURSOR://东南
if(w + e.getX()>20&& h + e.getY()>20){
w = w + e.getX();
h = h + e.getY();
this.setBounds(x, y, w, h);
}
break;
case Cursor.S_RESIZE_CURSOR://南
if(h+e.getY()>20){
h = h + e.getY();
this.setBounds(x, y, w, h);
}
break;
case Cursor.SW_RESIZE_CURSOR://西南
if(w-e.getX()>20&& h+e.getY()>20){
w = w - e.getX();
h = h + e.getY();
this.setBounds(x + e.getX(), y,w, h);
}
break;
case Cursor.W_RESIZE_CURSOR://西
if(w-e.getX()>20){
w = w - e.getX();
this.setBounds(x + e.getX(), y,w, h);
}
break;
case Cursor.DEFAULT_CURSOR://拖动操作
if(e.getComponent()==this){
this.setBounds(x+e.getX(),y+e.getY(),w,h);
}
default:
break;
}
//重定位各缩放点坐标位置
northWest.setBounds(0, 0, 5, 5);
north.setBounds((w - 3) / 2, 0, 5, 5);
northEast.setBounds(w - 5, 0, 5, 5);
east.setBounds(w - 5, (h - 3) / 2,5, 5);
southEast.setBounds(w - 5, h - 5, 5, 5);
south.setBounds((w - 3) / 2, h - 5,5, 5);
southWest.setBounds(0, h - 5, 5, 5);
west.setBounds(0, (h - 3) / 2, 5, 5);
//重绘
this.repaint();
}
}

public void mouseMoved(MouseEvent e) {
// TODO Auto-generated method stub

}

public void paint(Graphics g) {
super.paint(g);
//绘制图片在中央
g.drawImage(this.imageIcon.getImage(), 5, 5, this.getWidth() - 10,
this.getHeight() - 10, this);
}
}
}

来自 “ ITPUB博客 ” ,链接:http://blog.itpub.net/374079/viewspace-130905/,如需转载,请注明出处,否则将追究法律责任。

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