调整图标大小以适应 Java 中的 JButton? [英] Resizing icon to fit on JButton in Java?
问题描述
每当我为 JButton 设置图标时，它的大小总是不正确.如何调整图标大小以完全适合按钮?
Whenever I set an icon for my JButton it is always not sized correctly. How can I resize the icon to fit the button fully?
final JButton btnSanic = new JButton();
Image img = icon.getImage();
Image newimg = img.getScaledInstance(width, height, java.awt.Image.SCALE_SMOOTH);
icon = new ImageIcon(newimg);
btnSanic.setIcon(icon);
推荐答案
有许多问题.首先，所有 Swing 组件都不会自动缩放图像.当然，这可能是个好主意，但考虑到有效执行所需的时间和处理量，我理解他们为什么不这样做，因此您需要完成所有工作...
There are any number of issues. To start with, all Swing components DON'T auto scale images. Sure, might be a nice idea, but given the amount of time and processing required to do it efficiently, I understand why they don't, so you need to do all the work...
您还应该记住，组件的大小在布局后才确定.虽然您可以提供您可能喜欢的所有大小调整提示，但布局管理器完全有权忽略这些提示中的一个或多个.
You should also remember, that the size of a component is not determined until it is laid out. And while you can provide all the sizing hints you might like, the layout manager is well within its rights to ignore one or more of these hints.
而不是希望"你知道按钮的大小，你应该使用 ComponentListener API 来接收组件实际调整大小的通知......
Instead of "hoping" you know the size of the button, you should make use of the ComponentListener API to receive notifications of when the component is actually resized...
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Image;
import java.awt.Insets;
import java.awt.event.ComponentAdapter;
import java.awt.event.ComponentEvent;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class TestButton {
public static void main(String[] args) {
new TestButton();
}
private BufferedImage master;
public TestButton() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
try {
master = ImageIO.read(new File("C:\svg\Revert 256x256.png"));
JButton btn = new JButton() {
@Override
public Dimension getPreferredSize() {
return new Dimension(90, 50);
}
};
btn.addComponentListener(new ComponentAdapter() {
@Override
public void componentResized(ComponentEvent e) {
JButton btn = (JButton) e.getComponent();
Dimension size = btn.getSize();
Insets insets = btn.getInsets();
size.width -= insets.left + insets.right;
size.height -= insets.top + insets.bottom;
if (size.width > size.height) {
size.width = -1;
} else {
size.height = -1;
}
Image scaled = master.getScaledInstance(size.width, size.height, java.awt.Image.SCALE_SMOOTH);
btn.setIcon(new ImageIcon(scaled));
}
});
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(btn);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
} catch (IOException exp) {
exp.printStackTrace();
}
}
});
}
}
注意:这个例子远非优化，只是提供了一个可能的解决方案的广泛概念......
Note: This example is far from optimised, but simply provides a broad concept of a possible solution...
现在，警告一下.Image#getScaledInstance 既不是最快也不是最好的缩放算法...
Now, a word of warning. Image#getScaledInstance is neither the fastest or greatest of scaling algorithms...
看看...
欲知更多详情...
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