How to Automatically Resize Images within a JLabel?

Automatic Image Resizing on a JLabel

When displaying an image on a JPanel using a JLabel, it's often desired to automatically adjust the image's size to fit the label's dimensions. By default, the JLabel will maintain the original image's aspect ratio and scale it to fit within the label's available space.

To achieve automatic image resizing, one approach is to utilize a custom component that extends JPanel and handles the scaled image rendering. This allows for more control over the scaling behavior, such as specifying whether to fit or fill the image within the label.

Resizing Options

There are two main resizing options available for images on a JLabel:

• Fit: The image will be scaled to fit within the label's bounds while maintaining its original aspect ratio.
• Fill: The image will be stretched to fill the entire label, potentially distorting the aspect ratio.

Custom Component for Resizable Images

The following code showcases a custom component, ScalablePane, that manages image scaling based on the fit/fill option:

public class ScalablePane extends JPanel {

    // ... (code omitted for brevity)

    @Override
    protected void paintComponent(Graphics g) {
        // Draw the scaled image
        super.paintComponent(g);
        if (scaled != null) {
            g.drawImage(scaled, x, y, this);
        } else if (master != null) {
            g.drawImage(master, x, y, this);
        }
    }

    // ... (code omitted for brevity)

}

Example Usage

To use the ScalablePane component, you can instantiate it and set the desired image:

ScalablePane scalablePane = new ScalablePane(image);

// Set the fit/fill option
scalablePane.setToFit(true); // Fit image within the component

// Add the component to your JPanel
yourJPanel.add(scalablePane);

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