大家好，我對在 a 中繪制的圖像有疑問JPanel。將圖像繪制到面板時沒有問題。當我向上或向下滾動圖像時出現問題。當再次返回該部分時，在視口中未看到的圖像部分會被涂成白色。我 BufferedImage 在JPanel. 我還可以使用調整圖像大小AffineTransform。問題是當我JScollPane在圖像中添加 a 時，每當我向上或向下滾動時，scrollpane圖像的某些部分就會消失..我也嘗試過使用drawRenderedImage它確實解決了滾動的問題，但它搞砸了其他功能。這是我能做的最簡潔的代碼；package convert;import java.awt.*;import java.awt.event.*;import java.awt.geom.*;import java.awt.image.BufferedImage;import java.io.*;import java.net.*;import java.util.ArrayList;import javax.imageio.ImageIO;import javax.swing.*;import javax.swing.event.*;public class ZoomTest { public static void main(String[] args) { ImagePanel panel = new ImagePanel(); JFrame f = new JFrame(); f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); f.getContentPane().add(new JScrollPane(panel)); f.setSize(1200, 1200); f.setLocationRelativeTo(null); f.setVisible(true); }}class ImagePanel extends JPanel { BufferedImage image; double scale; public ImagePanel() { loadImage(); scale = .38; addMouseWheelListener(new MouseWheelListener() { @Override public void mouseWheelMoved(MouseWheelEvent e) { int rotation = e.getWheelRotation(); if (rotation < 0) { scale -= .05; } else { scale += .05; } if (scale < 0) { scale = 0; } revalidate(); repaint(); } }); } @Override protected void paintComponent(Graphics g) { super.paintComponent(g); Graphics2D g2 = (Graphics2D) g; double x = (getWidth() - scale * image.getWidth()) / 2; double y = (getHeight() - scale * image.getHeight()) / 2; AffineTransform at = new AffineTransform(); at.translate(x, y); at.scale(scale, scale); g2.setTransform(at); g2.drawImage(image, 0, 0, null); }
2 回答
holdtom
TA貢獻1805條經驗 獲得超10個贊
看看Graphics2D#drawImage(Image, AffineTransform, ImageObserver)?？赡苡袔椭?/p>
package convert;
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.awt.image.BufferedImage;
import java.io.*;
import java.net.*;
import java.util.ArrayList;
import javax.imageio.ImageIO;
import javax.swing.*;
import javax.swing.event.*;
public class ZoomTest2 {
? public static void main(String[] args) {
? ? ImagePanel panel = new ImagePanel();
? ? JFrame f = new JFrame();
? ? f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
? ? f.getContentPane().add(new JScrollPane(panel));
? ? f.setSize(1200, 1200);
? ? f.setLocationRelativeTo(null);
? ? f.setVisible(true);
? }
}
class ImagePanel extends JPanel {
? BufferedImage image;
? double scale;
? public ImagePanel() {
? ? loadImage();
? ? scale = .38;
? ? addMouseWheelListener(new MouseWheelListener() {
? ? ? @Override
? ? ? public void mouseWheelMoved(MouseWheelEvent e) {
? ? ? ? int rotation = e.getWheelRotation();
? ? ? ? if (rotation < 0) {
? ? ? ? ? scale -= .05;
? ? ? ? } else {
? ? ? ? ? scale += .05;
? ? ? ? }
? ? ? ? if (scale < 0) {
? ? ? ? ? scale = 0;
? ? ? ? }
? ? ? ? revalidate();
? ? ? ? repaint();
? ? ? }
? ? });
? }
? @Override
? protected void paintComponent(Graphics g) {
? ? super.paintComponent(g);
? ? Graphics2D g2 = (Graphics2D) g.create();
? ? double x = (getWidth() - scale * image.getWidth()) / 2;
? ? double y = (getHeight() - scale * image.getHeight()) / 2;
? ? AffineTransform at = new AffineTransform();
? ? at.translate(x, y);
? ? at.scale(scale, scale);
? ? // g2.setTransform(at);
? ? // g2.drawImage(image, 0, 0, this);
? ? g2.drawImage(image, at, this);
? ? // or:
? ? // AffineTransform atf = g2.getTransform();
? ? // atf.concatenate(at);
? ? // g2.setTransform(atf);
? ? // g2.drawImage(image, 0, 0, this);
? ? g2.dispose();
? }
? public Dimension getPreferredSize() {
? ? int w = (int)(scale * image.getWidth());
? ? int h = (int)(scale * image.getHeight());
? ? return new Dimension(w, h);
? }
? private void loadImage() {
? ? String fileName = "aaa.png";
? ? try {
? ? ? image = ImageIO.read(new File(fileName));
? ? } catch (Exception e) {
? ? ? e.printStackTrace();
? ? }
? }
}
MMTTMM
TA貢獻1869條經驗 獲得超4個贊
這是您的問題的解決方案。我在自定義繪畫方面也很不走運，所以我的解決方案是直接更新鼠標滾輪上的圖像并將其設置為標簽。
import java.awt.Image;
import java.awt.event.MouseWheelEvent;
import java.awt.event.MouseWheelListener;
import java.awt.image.BufferedImage;
import java.io.File;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JScrollPane;
import javax.swing.SwingConstants;
public class ZoomTest {
public static void main(String[] args) {
ImagePanel panel = new ImagePanel();
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.getContentPane().add(new JScrollPane(panel));
f.setSize(1000, 1000);
f.setLocationRelativeTo(null);
f.setVisible(true);
}
}
class ImagePanel extends JLabel {
BufferedImage image;
double scale;
public ImagePanel() {
setHorizontalAlignment(SwingConstants.CENTER);
loadImage();
scale = .38;
updateImage();
addMouseWheelListener(new MouseWheelListener() {
@Override
public void mouseWheelMoved(MouseWheelEvent e) {
int rotation = e.getWheelRotation();
if (rotation < 0) {
scale -= .05;
} else {
scale += .05;
}
if (scale < 0) {
scale = 0;
}
updateImage();
revalidate();
repaint();
}
});
}
private void updateImage() {
int w = (int) (scale * image.getWidth());
int h = (int) (scale * image.getHeight());
setIcon(new ImageIcon(image.getScaledInstance(w, h, Image.SCALE_SMOOTH)));
}
private void loadImage() {
String fileName = "c:\\users\\john ebarita\\downloads\\lorem-ipsum-1.jpg";
try {
image = ImageIO.read(new File(fileName));
} catch (Exception e) {
e.printStackTrace();
}
}
}
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