就个人而言，我可以在将其应用于标签之前调整其大小，或者使用aJPanel进行绘画。JLabel必须拖延很多功能。
举例来说，您遇到的问题是您实际上是在使用 该图像setIcon来设置图像，但是却 在其顶部paintComponent绘制了另一个（初始）图像
您的自定义标签将aImageIcon作为初始参数并将其绘制为初始参数
private static class MyJLabel extends JLabel { private ImageIcon img = null; public MyJLabel(ImageIcon img) { super(); this.img = img; } @Override public void paintComponent(Graphics g) { super.paintComponent(g); g.drawImage(img.getImage(), 0, 0, getWidth(), getHeight(), this); }}You initialise it as such…
label = new MyJLabel(new ImageIcon(img));
It should be noted that if you used the
Iconsupport of
JLabel, this…
label.setPreferredSize(dims);
会无关紧要，因为JLabel会使用图标的大小来确定其
首选的大小……但无论如何……
然后，使用此按钮更新图标。
img = image;if (label != null) { label.setIcon(new ImageIcon(img)); label.repaint();}应该指出的是，根据您的示例，这实际上是在EDT之外调用的，这很危险，并可能导致油漆变脏。
但setIcon永远不会改变的价值img范围内MyLabel，所以当你的
paintComponent方法被调用时，你实际上是画了你的图标
已经在更新提供…
// Paint the new Iconsuper.paintComponent(g);// Paint the old/initial image...g.drawImage(img.getImage(), 0, 0, getWidth(), getHeight(), this);
Updated
就个人而言，我要做的是使用a之类的东西创建一个自定义组件，JPanel并根据
面板的当前大小缩放原始图像，例如……
现在，通常情况下，在执行图像缩放时，我更喜欢使用Java中演示的分治方法：维护JPanel
背景图像的宽高比，但是在此示例中，我只是AffineTransform为了简单起见使用
import java.awt.Dimension;import java.awt.EventQueue;import java.awt.Graphics;import java.awt.Graphics2D;import java.awt.HeadlessException;import java.awt.Image;import java.awt.geom.AffineTransform;import java.io.File;import java.io.IOException;import javax.imageio.ImageIO;import javax.swing.Jframe;import javax.swing.JPanel;import javax.swing.UIManager;import javax.swing.UnsupportedLookAndFeelException;public class ScalableImageExample { public static void main(String[] args) { new ScalableImageExample(); } public ScalableImageExample() { EventQueue.invokeLater(new Runnable() { @Override public void run() { try { UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName()); } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) { ex.printStackTrace(); } try { ResizableImagePane pane = new ResizableImagePane(); pane.setImage(...); Jframe frame = new Jframe("Testing"); frame.setDefaultCloseOperation(Jframe.EXIT_ON_CLOSE); frame.add(pane); frame.pack(); frame.setLocationRelativeTo(null); frame.setVisible(true); } catch (IOException exp) { exp.printStackTrace(); } } }); } public class ResizableImagePane extends JPanel { private Image img; public ResizableImagePane() { } public void setImage(Image value) { if (img != value) { Image old = img; this.img = value; firePropertyChange("image", old, img); revalidate(); repaint(); } } public Image getImage() { return img; } @Override public Dimension getPreferredSize() { return img == null ? new Dimension(200, 200) : new Dimension(img.getWidth(this), img.getHeight(this)); } @Override protected void paintComponent(Graphics g) { super.paintComponent(g); if (img != null) { Graphics2D g2d = (Graphics2D) g.create(); int width = getWidth(); int height = getHeight(); double scaleFactor = getScaleFactorToFit(new Dimension(img.getWidth(this), img.getHeight(this)), getSize()); int x = (int)((width - (img.getWidth(this) * scaleFactor)) / 2); int y = (int)((height - (img.getHeight(this) * scaleFactor)) / 2); AffineTransform at = new AffineTransform(); at.translate(x, y); at.scale(scaleFactor, scaleFactor); g2d.setTransform(at); g2d.drawImage(img, 0, 0, this); g2d.dispose(); } } public double getScaleFactor(int iMasterSize, int iTargetSize) { return (double) iTargetSize / (double) iMasterSize; } public double getScaleFactorToFit(Dimension original, Dimension toFit) { double dScale = 1d; if (original != null && toFit != null) { double dScaleWidth = getScaleFactor(original.width, toFit.width); double dScaleHeight = getScaleFactor(original.height, toFit.height); dScale = Math.min(dScaleHeight, dScaleWidth); } return dScale; } }}
