当我最大化我的应用程序时,JPanel内部的图像不会随之调整大小。如何在窗口最大化时调整JPanel及其内容?
编辑:我正在使用BufferedImage
答案 0 :(得分:5)
这是一个开放式的问题。
你想缩放以填充或缩放以适应该区域,还是不关心宽高比?
填充比例和适合比例
之间的差异
此示例将对帧大小的变化作出反应,并实时重新缩放图像。
public class TestScaling {
public static void main(String[] args) {
new TestScaling();
}
public TestScaling() {
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 ScalingPane());
frame.setSize(200, 200);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class ScalingPane extends javax.swing.JPanel {
private BufferedImage image;
public ScalingPane() {
try {
image = ImageIO.read(getClass().getResource("/AtDesk.png"));
} catch (IOException ex) {
ex.printStackTrace();
}
setBackground(Color.red);
}
public double getScaleFactor(int iMasterSize, int iTargetSize) {
double dScale = 1;
dScale = (double) iTargetSize / (double) iMasterSize;
return dScale;
}
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;
}
public double getScaleFactorToFill(Dimension masterSize, Dimension targetSize) {
double dScaleWidth = getScaleFactor(masterSize.width, targetSize.width);
double dScaleHeight = getScaleFactor(masterSize.height, targetSize.height);
double dScale = Math.max(dScaleHeight, dScaleWidth);
return dScale;
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
double scaleFactor = Math.min(1d, getScaleFactorToFit(new Dimension(image.getWidth(), image.getHeight()), getSize()));
// double scaleFactor = Math.min(1d, getScaleFactorToFill(new Dimension(image.getWidth(), image.getHeight()), getSize()));
int scaleWidth = (int) Math.round(image.getWidth() * scaleFactor);
int scaleHeight = (int) Math.round(image.getHeight() * scaleFactor);
Image scaled = image.getScaledInstance(scaleWidth, scaleHeight, Image.SCALE_SMOOTH);
int width = getWidth() - 1;
int height = getHeight() - 1;
int x = (width - scaled.getWidth(this)) / 2;
int y = (height - scaled.getHeight(this)) / 2;
g.drawImage(scaled, x, y, this);
}
}
}
更好的解决方案是使用某种背景线程来对组件大小的变化作出反应,并在背景中重新缩放原始图像,从而提供低质量和高质量的比例。
还应该注意Image.getScaledInstance
既不是最快或最高质量的缩放算法。有关详细信息,请查看The Perils of Image.getScaledInstance。
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答案 1 :(得分:2)
一种粗暴的方式......
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.draw(image,0,0,getWidth(),getHeight(),this);
// ..