以下是我的代码。我试图通过移动滑块来实现缩放。 然而，效果并没有表现出来。请帮帮我。我搞不清楚了。我是java新手，我正在使用Netbeans。
我还需要单击缩放的图像并在实际图像中显示相应的点。我怎样才能做到这一点？
public class TrialZoom extends javax.swing.JFrame {
/**
* Creates new form TrialZoom
*/
private float scaleX, scaleY;
Point p = new Point();
Point q = new Point();
Vector<Point> v = new Vector();
Vector<Float> v_scale = new Vector();
public TrialZoom() {
initComponents();
}
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jPanel1 = new javax.swing.JPanel();
jButton1 = new javax.swing.JButton();
jPanel2 = new javax.swing.JPanel();
jPanel3 = new javax.swing.JPanel();
jSlider2 = new javax.swing.JSlider();
jPanel4 = new javax.swing.JPanel();
jLabel1 = new javax.swing.JLabel();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jPanel1.setLayout(new java.awt.GridLayout(1, 0));
jButton1.setText("Done");
jButton1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton1ActionPerformed(evt);
}
});
jPanel1.add(jButton1);
getContentPane().add(jPanel1, java.awt.BorderLayout.PAGE_END);
jPanel2.setLayout(new java.awt.BorderLayout());
jPanel3.setLayout(new java.awt.GridLayout(1, 0));
jSlider2.addChangeListener(new javax.swing.event.ChangeListener() {
public void stateChanged(javax.swing.event.ChangeEvent evt) {
jSlider2StateChanged(evt);
}
});
jPanel3.add(jSlider2);
jPanel2.add(jPanel3, java.awt.BorderLayout.PAGE_END);
jLabel1.setHorizontalAlignment(javax.swing.SwingConstants.CENTER);
jLabel1.addMouseListener(new java.awt.event.MouseAdapter() {
public void mouseClicked(java.awt.event.MouseEvent evt) {
jLabel1MouseClicked(evt);
}
});
javax.swing.GroupLayout jPanel4Layout = new javax.swing.GroupLayout(jPanel4);
jPanel4.setLayout(jPanel4Layout);
jPanel4Layout.setHorizontalGroup(
jPanel4Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 400, Short.MAX_VALUE)
.addGroup(jPanel4Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel4Layout.createSequentialGroup()
.addGap(0, 200, Short.MAX_VALUE)
.addComponent(jLabel1)
.addGap(0, 200, Short.MAX_VALUE)))
);
jPanel4Layout.setVerticalGroup(
jPanel4Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 251, Short.MAX_VALUE)
.addGroup(jPanel4Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel4Layout.createSequentialGroup()
.addGap(0, 125, Short.MAX_VALUE)
.addComponent(jLabel1)
.addGap(0, 126, Short.MAX_VALUE)))
);
jPanel2.add(jPanel4, java.awt.BorderLayout.CENTER);
getContentPane().add(jPanel2, java.awt.BorderLayout.CENTER);
pack();
}// </editor-fold>
private void jSlider2StateChanged(javax.swing.event.ChangeEvent evt) {
// TODO add your handling code here:
int val = ((JSlider) evt.getSource()).getValue();
setScale(val * .01f, val * .01f);
}
private void jLabel1MouseClicked(java.awt.event.MouseEvent evt) {
setCursor(java.awt.Cursor.getPredefinedCursor(java.awt.Cursor.CROSSHAIR_CURSOR));
p = evt.getPoint();
q = SwingUtilities.convertPoint(evt.getComponent(), p, this);
v.add(p);
v_scale.add(scaleX);
v_scale.add(scaleY);
double c = q.getX();
double d = q.getY();
String x1 = Double.toString(p.getX());
String x2 = Double.toString(p.getY());
Graphics g = this.getGraphics();
paint(g, (int) c, (int) d); // TODO add your handling code here:
}
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
System.out.println(p.getX() + " " + p.getY() + " " + q.getX() + " " + q.getY());
float sx=v_scale.remove(0);
float sy=v_scale.remove(0);
System.out.println(sx+" "+sy);
dispose();
// TODO add your handling code here:
}
public Vector<Point> first(ImageIcon icon) {
jLabel1.setIcon(icon);
return return_vector();
}
public void paint(Graphics g, int a, int b) {
g.setColor(Color.RED);
g.drawRect(a - 1, b - 1, 3, 3);
g.fillRect(a, b, 2, 2);
}
@Override
public Dimension getPreferredSize() {
int prefWidth;
prefWidth = (int) (jLabel1 == null ? 0 : jPanel4.getWidth() * scaleX);
int prefHeight;
prefHeight = (int) (jLabel1 == null ? 0 : jPanel4.getHeight() * scaleY);
return new Dimension(prefWidth, prefHeight);
}
public void paintComponent(Graphics g) {
if (jLabel1 == null) {
return;
}
int w = (int) (jLabel1.getWidth() * scaleX);
int h = (int) (jLabel1.getHeight() * scaleY);
int x = (getWidth() - w) / 2;
int y = (getHeight() - h) / 2;
ImageIcon img_icon=(ImageIcon) jLabel1.getIcon();
g.drawImage(img_icon.getImage(), x, y, w, h, null);
}
public void setScale(float x, float y) {
this.scaleX = x;
this.scaleY = y;
jLabel1.revalidate();
jLabel1.repaint();
}
public Vector<Point> return_vector() {
return this.v;
}
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
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(TrialZoom.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(TrialZoom.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(TrialZoom.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(TrialZoom.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() {
new TrialZoom().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JButton jButton1;
private javax.swing.JLabel jLabel1;
private javax.swing.JPanel jPanel1;
private javax.swing.JPanel jPanel2;
private javax.swing.JPanel jPanel3;
private javax.swing.JPanel jPanel4;
private javax.swing.JSlider jSlider2;
// End of variables declaration
}
答案 0 :(得分：1)
首先，从能够管理图像和缩放的组件开始。这应该是你可以做到的自包含。这使您可以解耦程序并专注于应用程序的个人职责。
接下来，您需要维护一个标准化点列表。对它们进行标准化的原因是为了确保在缩放图像时，点将继续在正确的位置渲染...
请查看Performing Custom Painting了解详情
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Point;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.geom.Point2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JSlider;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
public class ZoomExample {
public static void main(String[] args) {
new ZoomExample();
}
public ZoomExample() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new ZoomPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class ZoomPane extends JPanel {
private JSlider slider;
private ZoomImagePane zoomImagePane;
public ZoomPane() {
zoomImagePane = new ZoomImagePane();
slider = new JSlider(1, 200);
slider.addChangeListener(new ChangeListener() {
@Override
public void stateChanged(ChangeEvent e) {
zoomImagePane.setScale((float) slider.getValue() / 100f);
}
});
setLayout(new BorderLayout());
add(slider, BorderLayout.SOUTH);
add(zoomImagePane);
slider.setValue(100);
}
}
public class ZoomImagePane extends JPanel {
private float scale = 0f;
private BufferedImage master;
private Image scaled;
private List<Point2D> clickPoints;
public ZoomImagePane() {
clickPoints = new ArrayList<>(25);
try {
master = ImageIO.read(new File("/path/to/image"));
setScale(1f);
} catch (IOException ex) {
ex.printStackTrace();
}
addMouseListener(new MouseAdapter() {
@Override
public void mousePressed(MouseEvent e) {
Point p = e.getPoint();
Point2D scaledPoint = new Point2D.Float();
int xOffset = (getWidth() - scaled.getWidth(null)) / 2;
int yOffset = (getHeight() - scaled.getHeight(null)) / 2;
float x = (float)(p.x - xOffset) / (float)scaled.getWidth(null);
float y = (float)(p.y - yOffset) / (float)scaled.getHeight(null);
scaledPoint.setLocation(x, y);
clickPoints.add(scaledPoint);
repaint();
}
});
}
protected void setScale(float value) {
if (scale != value) {
scale = value;
scaled = master.getScaledInstance((int) ((float) master.getWidth() * scale), -1, Image.SCALE_SMOOTH);
revalidate();
repaint();
}
}
@Override
public Dimension getPreferredSize() {
Dimension size = new Dimension(200, 200);
if (scaled != null) {
size = new Dimension(scaled.getWidth(this), scaled.getHeight(this));
}
return size;
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (scaled != null) {
int x = (getWidth() - scaled.getWidth(this)) / 2;
int y = (getHeight() - scaled.getHeight(this)) / 2;
Graphics2D g2d = (Graphics2D) g.create();
g2d.drawImage(scaled, x, y, this);
g2d.setColor(Color.RED);
for (Point2D p : clickPoints) {
int xPos = x + ((int)(p.getX() * scaled.getWidth(this)) - 5);
int yPos = y + ((int)(p.getY() * scaled.getHeight(this)) - 5);
g2d.fillOval(xPos, yPos, 10, 10);
}
g2d.dispose();
}
}
}
}