我正在以下代码中执行缩放操作。窗体中的两个 slider 是用于缩放仿射变换的 X 和 Y 参数。我的问题是，当我更改 slider 时，图像会缩放，如何动态调整正在绘制该图像的 jpanel 的大小。
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
package newpackage;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.geom.AffineTransform;
import java.awt.image.AffineTransformOp;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
/**
*
* @author ABC
*/
public class Swon extends javax.swing.JFrame {
final BufferedImage img;
/**
* Creates new form Swon
*/
public Swon() throws IOException{
BufferedImage im=ImageIO.read(new File("C:/Users/ABC/Desktop/I-RIX2012_Final_logo_out.jpg"));
this.img=new BufferedImage(im.getWidth(),im.getWidth(),BufferedImage.TYPE_BYTE_GRAY);
this.img.getGraphics().drawImage(im, 0, 0, null);
initComponents();
}
/**
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always
* regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jPanel1 = new javax.swing.JPanel(){
// @Override
// public void paint(Graphics g)
// {
// super.paint(g);
// g.drawImage(img.getScaledInstance(this.getWidth(), this.getHeight(), Image.SCALE_FAST),0,0,null);
// }
};
jSlider1 = new javax.swing.JSlider();
jSlider2 = new javax.swing.JSlider();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jPanel1.setBorder(new javax.swing.border.SoftBevelBorder(javax.swing.border.BevelBorder.RAISED));
jPanel1.addComponentListener(new java.awt.event.ComponentAdapter() {
public void componentResized(java.awt.event.ComponentEvent evt) {
jPanel1ComponentResized(evt);
}
});
javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
jPanel1.setLayout(jPanel1Layout);
jPanel1Layout.setHorizontalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 268, Short.MAX_VALUE)
);
jPanel1Layout.setVerticalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 209, Short.MAX_VALUE)
);
jSlider1.setMaximum(5);
jSlider1.setValue(1);
jSlider1.addChangeListener(new javax.swing.event.ChangeListener() {
public void stateChanged(javax.swing.event.ChangeEvent evt) {
jSlider1StateChanged(evt);
}
});
jSlider2.setMaximum(5);
jSlider2.setValue(1);
jSlider2.addChangeListener(new javax.swing.event.ChangeListener() {
public void stateChanged(javax.swing.event.ChangeEvent evt) {
jSlider2StateChanged(evt);
}
});
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(45, 45, 45)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jSlider2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jSlider1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
.addContainerGap(242, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(36, 36, 36)
.addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addGap(33, 33, 33)
.addComponent(jSlider1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addComponent(jSlider2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(38, Short.MAX_VALUE))
);
pack();
}// </editor-fold>
private void jPanel1ComponentResized(java.awt.event.ComponentEvent evt) {
// TODO add your handling code here:
// AffineTransform f=new AffineTransform();
}
private void jSlider1StateChanged(javax.swing.event.ChangeEvent evt) {
// TODO add your handling code here:
AffineTransform scale = AffineTransform.getScaleInstance(jSlider1.getValue(),jSlider2.getValue());
AffineTransformOp op3 = new AffineTransformOp(scale, AffineTransformOp.TYPE_BILINEAR);
BufferedImage scaling = new BufferedImage(this.img.getHeight(), this.img.getWidth(), this.img.getType());
BufferedImage img1=op3.filter(this.img, scaling);
jPanel1.getGraphics().drawImage(img1.getScaledInstance(jPanel1.getWidth(), jPanel1.getHeight(), Image.SCALE_FAST), 0, 0, null);
}
private void jSlider2StateChanged(javax.swing.event.ChangeEvent evt) {
// TODO add your handling code here:
AffineTransform scale = AffineTransform.getScaleInstance(jSlider1.getValue(),jSlider2.getValue());
AffineTransformOp op3 = new AffineTransformOp(scale, AffineTransformOp.TYPE_BILINEAR);
BufferedImage scaling = new BufferedImage(this.img.getHeight(), this.img.getWidth(), this.img.getType());
BufferedImage img1=op3.filter(this.img, scaling);
jPanel1.getGraphics().drawImage(img1.getScaledInstance(jPanel1.getWidth(), jPanel1.getHeight(), Image.SCALE_FAST), 0, 0, null);
}
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
/* Set the Nimbus look and feel */
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
* For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(Swon.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(Swon.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(Swon.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(Swon.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
try {
new Swon().setVisible(true);
} catch (IOException ex) {
Logger.getLogger(Swon.class.getName()).log(Level.SEVERE, null, ex);
}
}
});
}
// Variables declaration - do not modify
public javax.swing.JPanel jPanel1;
private javax.swing.JSlider jSlider1;
private javax.swing.JSlider jSlider2;
// End of variables declaration
}
最佳答案
好吧，首先，不要执行 this.img.getGraphics().drawImage(im, 0, 0, null)，当面板重绘时，图像不会更新。您需要重写 JComponent 的 paintComponent 方法(首选 JPanel)并以适当的比例重新绘制图像。
其次，您需要将图像面板放置到能够真正关心面板大小的布局上(例如GridBagLayout)。为此，请重写 getPreferredSize 方法并返回缩放图像的大小...
public class ResizableImagePane {
public static void main(String[] args) {
new ResizableImagePane();
}
public ResizableImagePane() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException ex) {
} catch (InstantiationException ex) {
} catch (IllegalAccessException ex) {
} catch (UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new ScalerPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
protected class ScalerPane extends JPanel {
private JSlider slider;
private ImagePane imagePane;
public ScalerPane() {
setLayout(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridx = 0;
gbc.gridy = 0;
imagePane = new ImagePane();
add(imagePane, gbc);
gbc.gridy = 1;
gbc.weightx = 0;
gbc.weighty = 0;
gbc.fill = GridBagConstraints.HORIZONTAL;
slider = new JSlider();
slider.setMinimum(1);
slider.setMaximum(100);
gbc.weightx = 1;
gbc.weighty = 1;
gbc.anchor = GridBagConstraints.SOUTH;
gbc.fill = GridBagConstraints.HORIZONTAL;
add(slider, gbc);
slider.addChangeListener(new ChangeListener() {
@Override
public void stateChanged(ChangeEvent ce) {
imagePane.setZoom(slider.getValue() / 100f);
}
});
slider.setValue(100);
}
}
protected class ImagePane extends JPanel {
private BufferedImage background;
private Image scaled;
private float zoom;
public ImagePane() {
try {
background = ImageIO.read(new File("path/to/your/image"));
} catch (IOException ex) {
ex.printStackTrace();
}
setZoom(1f);
setBorder(new LineBorder(Color.RED));
}
@Override
public Dimension getPreferredSize() {
return new Dimension(scaled.getWidth(this), scaled.getHeight(this));
}
public void setZoom(float zoom) {
this.zoom = zoom;
int width = Math.round(background.getWidth() * zoom);
scaled = background.getScaledInstance(width, -1, Image.SCALE_SMOOTH);
invalidate();
revalidate();
repaint();
}
public float getZoom() {
return zoom;
}
@Override
protected void paintComponent(Graphics grphcs) {
super.paintComponent(grphcs);
int x = (getWidth() - scaled.getWidth(this)) / 2;
int y = (getHeight() - scaled.getHeight(this)) / 2;
grphcs.drawImage(scaled, x, y, this);
}
}
}
关于java - Jpanel 在重新绘制时调整大小，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/12797933/