IconUtils.java

/*
 * IconUtils.java
 *
 * Created on April 14, 2005, 11:24 AM
 */

package edu.oregonstate.cartography.app;

import javax.swing.*;

/**
 * From the SUN Tutorial "How to Use Icons"<br>
 * 
 * The first argument to the ImageIcon constructor is relative to the location of
 * the class, and will be resolved to an absolute URL. The description argument is
 * a string that allows assistive technologies to help a visually impaired user
 * understand what information the icon conveys.<br>
 * 
 * Generally, applications provide their own set of images used as part of the
 * application, as is the case with the images used by many of our demos. You
 * should use the Class getResource method to obtain the path to the image.
 * This allows the application to verify that the image is available and to provide
 * sensible error handling if it is not. When the image is not part of the
 * application, getResource should not be used and the ImageIcon constructor is
 * used directly. For example: <br>
 * <code>
 * ImageIcon icon = new ImageIcon("/home/sharonz/images/middle.gif",
 *                               "a pretty but meaningless splat");
 * </code>
 * <br>
 * When you specify a filename or URL to an ImageIcon constructor, processing
 * is blocked until after the image data is completely loaded or the data location
 * has proven to be invalid. If the data location is invalid (but non-null), an
 * ImageIcon is still successfully created; it just has no size and, therefore,
 * paints nothing. As we showed in the loadImageIcon method, it's wise to first
 * verify that the URL points to an existing file before passing it to the
 * ImageIcon constructor.
 */
public class IconUtils {
    
    private IconUtils(){
    }
    
    /**
     * Returns an ImageIcon, or null if the name is invalid.
     * @param name The name of the file. The file must be in the folder ika/icons/
     * @param description String that allows assistive technologies to help a 
     * visually impaired user understand what information the icon conveys
     * @return The loaded ImageIcon or null if the icon cannot be loaded.
     */
    public static ImageIcon loadImageIcon(String name, String description) {
        
        try {
            String folder = "/edu/oregonstate/cartography/app/";
            java.net.URL imgURL = IconUtils.class.getResource(folder + name);
            if (imgURL != null) {
                ImageIcon imageIcon = new ImageIcon(imgURL, description);
                if (imageIcon.getIconWidth() == 0 
                        || imageIcon.getIconHeight() == 0)
                    imageIcon = null;
                return imageIcon;
            } else {
                System.err.println("Couldn't find icon file: " + name);
                return null;
            }
        } catch (Exception exc) {
            return null;
        }
        
    }
    
    /**
     * Changes the icon displayed in JOptionPane dialogs to the passed icon.
     * Error, information, question and warning dialogs will show this icon.
     * This will also replace the icon in ProgressMonitor dialogs.
     * @deprecated use setOptionPaneIconPath instead
     */
    public static void setOptionPaneIcons (String iconName) {
        String iconPath = "/ika/icons/" + iconName;
        LookAndFeel lf = UIManager.getLookAndFeel();
        if (lf != null) {
            Class iconBaseClass = lf.getClass();
            Object appIcon = LookAndFeel.makeIcon(iconBaseClass, iconPath);
            UIManager.put("OptionPane.errorIcon", appIcon);
            UIManager.put("OptionPane.informationIcon", appIcon);
            UIManager.put("OptionPane.questionIcon", appIcon);
            UIManager.put("OptionPane.warningIcon", appIcon);
        }
    }
    
    /**
     * Changes the icon displayed in JOptionPane dialogs to the passed icon.
     * Error, information, question and warning dialogs will show this icon.
     * This will also replace the icon in ProgressMonitor dialogs.
     * @param iconPath A path to the icon, e.g. /ika/icons/icon
     */
    public static void setOptionPaneIconPath (String iconPath) {
        LookAndFeel lf = UIManager.getLookAndFeel();
        if (lf != null) {
            Class iconBaseClass = lf.getClass();
            Object appIcon = LookAndFeel.makeIcon(iconBaseClass, iconPath);
            UIManager.put("OptionPane.errorIcon", appIcon);
            UIManager.put("OptionPane.informationIcon", appIcon);
            UIManager.put("OptionPane.questionIcon", appIcon);
            UIManager.put("OptionPane.warningIcon", appIcon);
        }
    }
    
}