5 replies to this topic

[Nicholas Adri Chandoke]

Here's the exception:
java.lang.UnsupportedOperationException: getGraphics() not valid for images created with createImage(producer)
I looked it up on the internet, but I couldn't get much from it.

Just for convenience, here's my code:

CODE

public class Letter {

    private Image image;
    private int x, y;
    private Graphics2D imageGraphics;
    private boolean tilted = false;
    private Component parent;

    public Letter(Component parent, Image image) {
        this.parent = parent;
        this.image = image;
        imageGraphics = (Graphics2D) image.getGraphics();
    }

    public void waddle(int direction) {
        switch (direction) {
            case SwingConstants.LEFT:
                if (!tilted) {
                    imageGraphics.rotate(-20);
                    tilted = true;
                } else {
                    imageGraphics.rotate(20);
                    tilted = false;
                } if (x - 2 >= parent.getX())
                    x -= 2;
                break;
            case SwingConstants.RIGHT:
                if (!tilted) {
                    imageGraphics.rotate(20);
                    tilted = true;
                } else {
                    imageGraphics.rotate(-20);
                    tilted = false;
                } if (x + 2 + getWidth() < parent.getWidth())
                    x += 2;
                break;
        }
    }

    public void jump() {
        Timer t = new Timer(60, new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                
            }
        });
        t.start();
    }

    public Image getImage() {
        return image;
    }

    public void setImage(Image newImage) {
        image = newImage;
    }

    public int getX() {return x;}

    public int getY() {return y;}

    public int getWidth() {return image.getWidth(parent);}

    public int getHeight() {return image.getHeight(parent);}

    public Rectangle getBounds() {
        return new Rectangle(x, y, getWidth(), getHeight());
    }

    public void setLocation(int x, int y) {
        this.x = x;
        this.y = y;
    }

    public void scale(float factor) {
        image = image.getScaledInstance((int) (getWidth() * factor), (int) (getWidth() * factor), Image.SCALE_DEFAULT);
    }

    public void die() {
        Timer deathTimer = new Timer(20, new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                if (getWidth() < 2 || getHeight() < 2) {
                    Timer t = (Timer) e.getSource();
                    t.stop();
                    try {
                        finalize();
                    } catch (Throwable ex) {
                        Logger.getLogger(Letter.class.getName()).log(Level.SEVERE, null, ex);
                    }
                } else {
                    y = parent.getHeight() / 2;
                    imageGraphics.rotate(-1);
                    scale(.85f);
                }
            }
        });
        deathTimer.start();
    }

    public final static Letter K(Component parent) {
        return new Letter(parent, (Image) Toolkit.getDefaultToolkit().getImage(Letter.class.getResource("/org/K.png")));
    }

    public final static Letter Z(Component parent) {
        return new Letter(parent, (Image) Toolkit.getDefaultToolkit().getImage(Letter.class.getResource("/org/Z.png")));
    }
}

If you're wondering about the Letter thing, it's an incredibly useless video game that I'm writing for kicks; you play in a non-side-scrolling two dimensional environment as a capital letter 'K'. At the opposite end
of the window is a 'Z'. When you touch the 'Z', then the 'K' object (used in the main class (not provided)) envokes the "die()" method. 'K' and 'Z' are Letters.

[Kraicheck]

The exception is pretty clear.
The Image object you provide to the constructor of the Letter class is created with the createImage method of the Toolkit class.
You can't use the getGraphics method on such an object.
Change the way you obtain to Image object and it should work.

[Nicholas Adri Chandoke]

... do you know how else to create an Image? I have tried using

CODE

new javax.swing.ImageIcon(Letter.class.getResource("URL Here")).getImage().getGraphics()...

but it still gives the same error.

[Captain Pierce]

Drop the call to getGraphics(). The purpose of a Graphics context is to render to an image, not get it for rendering elsewhere.

[Kraicheck]

You'll have to use an AffineTransform.
More info can be found here: Transforming Shapes, Text, and Images.

[Nicholas Adri Chandoke]

Just to close-up this topic, I've figured out how to get around this: the ImageIO class.