HUDs on Windows (finally)

I finally got around to making the Heads Up Display (HUD) use transparency on non-Mac platforms. I wanted to keep compatibility with Java 5, so I decided to use reflection to try and gracefully use the com.sun.awt.AWTUtilities.setWindowOpaque method. Here are the two utility methods I use to make a window non-opque:

    /**
     * Try's to make the given {@link Window} non-opqaue (transparent) across 
     * platforms and JREs. This method is not guaranteed to succeed, and will fail
     * silently if the given {@code Window} cannot be made non-opaque.
     * 
     * This method is useful, for example, when creating a HUD style window that 
     * is semi-transparent, and thus doesn't want the window background to be
     * drawn.
     * @param window the {@code Window} to make non-opaque.
     */
    public static void makeWindowNonOpaque(Window window) {
        // on the mac, simply setting the window's background color to be fully 
        // transparent makes the window non-opaque.
        window.setBackground(new Color(0, 0, 0, 0));
        // on non-mac platforms, try to use the facilities of Java 6 update 10.
        if (!PlatformUtils.isMac()) {
            quietlyTryToMakeWindowNonOqaque(window);
        }
    }

    /**
     * Trys to invoke {@code com.sun.awt.AWTUtilities.setWindowOpaque(window, false)} 
     * on the given {@link Window}. This will only work when running with JRE 6 update 10 
     * or higher. This method will silently fail if the method cannot be invoked.
     * @param window the {@code Window} to try and make non-opaque.
     */
    private static void quietlyTryToMakeWindowNonOqaque(Window window) {
        try {
            Class clazz = Class.forName("com.sun.awt.AWTUtilities");
            Method method = 
                    clazz.getMethod("setWindowOpaque", java.awt.Window.class, Boolean.TYPE);
            method.invoke(clazz, window, false);
        } catch (Exception e) {
            // silently ignore this exception.
        }
    }

This enhancement will be part of Mac Widgets for Java 0.9.5, which will hopefully be out in the next few weeks. If you want access earlier, you can either download the code and build it from the Subversion repository, or you can email me and I’ll send you the latest jar file.