ImagePreviewPanel.java

package forge;


import javax.swing.*;
import java.awt.Color;
import java.awt.*;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.io.File;


/**
 * <p>ImagePreviewPanel class.</p>
 *
 * @author Forge
 * @version $Id: $
 */
public class ImagePreviewPanel extends JPanel implements PropertyChangeListener {


    /** Constant <code>serialVersionUID=2163809931940286240L</code> */
    private static final long serialVersionUID = 2163809931940286240L;
    private int width, height;
    private ImageIcon icon;
    private Image image;
    /** Constant <code>ACCSIZE=155</code> */
    private static final int ACCSIZE = 155;
    private Color bg;

    /**
     * <p>Constructor for ImagePreviewPanel.</p>
     */
    public ImagePreviewPanel() {
        setPreferredSize(new Dimension(ACCSIZE, -1));
        bg = getBackground();
    }

    /** {@inheritDoc} */
    public void propertyChange(PropertyChangeEvent e) {
        String propertyName = e.getPropertyName();

        // Make sure we are responding to the right event.
        if (propertyName.equals(JFileChooser.SELECTED_FILE_CHANGED_PROPERTY)) {
            File selection = (File) e.getNewValue();
            String name;

            if (selection == null) return;
            else name = selection.getAbsolutePath();

            /*
            * Make reasonably sure we have an image format that AWT can
            * handle so we don't try to draw something silly.
            */
            if ((name != null)
                    && (name.toLowerCase().endsWith(".jpg") || name.toLowerCase().endsWith(".jpeg")
                    || name.toLowerCase().endsWith(".gif") || name.toLowerCase().endsWith(".png"))) {
                icon = new ImageIcon(name);
                image = icon.getImage();
                scaleImage();
                repaint();
            }
        }
    }

    /**
     * <p>scaleImage.</p>
     */
    private void scaleImage() {
        width = image.getWidth(this);
        height = image.getHeight(this);
        double ratio = 1.0;

        /* 
        * Determine how to scale the image. Since the accessory can expand
        * vertically make sure we don't go larger than 150 when scaling
        * vertically.
        */
        if (width >= height) {
            ratio = (double) (ACCSIZE - 5) / width;
            width = ACCSIZE - 5;
            height = (int) (height * ratio);
        } else {
            if (getHeight() > 150) {
                ratio = (double) (ACCSIZE - 5) / height;
                height = ACCSIZE - 5;
                width = (int) (width * ratio);
            } else {
                ratio = (double) getHeight() / height;
                height = getHeight();
                width = (int) (width * ratio);
            }
        }

        image = image.getScaledInstance(width, height, Image.SCALE_DEFAULT);
    }

    /** {@inheritDoc} */
    @Override
    public void paintComponent(Graphics g) {
        g.setColor(bg);

        /*
        * If we don't do this, we will end up with garbage from previous
        * images if they have larger sizes than the one we are currently
        * drawing. Also, it seems that the file list can paint outside
        * of its rectangle, and will cause odd behavior if we don't clear
        * or fill the rectangle for the accessory before drawing. This might
        * be a bug in JFileChooser.
        */
        g.fillRect(0, 0, ACCSIZE, getHeight());
        g.drawImage(image, getWidth() / 2 - width / 2 + 5, getHeight() / 2 - height / 2, this);
    }

}