How do I flip/translate a GObject?

[Cody Lancer]

The drawEngine() method creates the object I am trying to face in the opposite direction.

private void drawEngine(double x, double y) {
        drawCarFrame(x, y, Color.BLACK);
        drawSmokestack(x, y);
        drawCab(x, y);
        drawCowcatcher(x, y);
    }

/*
     * This is a helper method which draws the smokestack for the engine.
     */
    private void drawSmokestack(double x, double y) {
        GRect smokestack = new GRect(x + SMOKESTACK_INSET, y - CAR_HEIGHT - CAR_BASELINE - SMOKESTACK_HEIGHT, SMOKESTACK_WIDTH, SMOKESTACK_HEIGHT);
        smokestack.setFilled(true);
        smokestack.setFillColor(Color.BLACK);
        add(smokestack);
    }

    /*
     * This helper method draws the cab on the engine.
     */
    private void drawCab(double x, double y) {
        GRect cab = new GRect(x + CAR_WIDTH - CAB_WIDTH + CONNECTOR, y - CAR_HEIGHT - CAR_BASELINE - CAB_HEIGHT, CAB_WIDTH, CAB_HEIGHT);
        cab.setFilled(true);
        cab.setFillColor(Color.BLACK);
        add(cab);
    }

    /*
     * This helper method draws the cowcatcher on the engine.
     */
    private void drawCowcatcher(double x, double y) {
        GLine cowcatcher1 = new GLine(x + (SMOKESTACK_INSET/2) + 2, y - CAR_BASELINE - (CAR_HEIGHT/2), x + (SMOKESTACK_INSET/2) - 1 , y - CAR_BASELINE);
        cowcatcher1.setColor(Color.BLACK);
        add(cowcatcher1);
        GLine cowcatcher2 = new GLine(x + (SMOKESTACK_INSET/2) + 2, y - CAR_BASELINE - (CAR_HEIGHT/2), x + (SMOKESTACK_INSET/2) - 4 ,y - CAR_BASELINE);
        cowcatcher2.setColor(Color.BLACK);
        add(cowcatcher2);

    }

/*
     * This method draws the frame that is used for all of the cars.
     */
    private void drawCarFrame(double x, double y, Color color) {
        double x0 = x + CONNECTOR;
        double y0 = y - CAR_BASELINE;
        double top = y0 - CAR_HEIGHT;
        add(new GLine(x, y0, x + CAR_WIDTH + 2 * CONNECTOR, y0));
        drawWheel(x0 + WHEEL_INSET, y - WHEEL_RADIUS);
        drawWheel(x0 + CAR_WIDTH - WHEEL_INSET, y - WHEEL_RADIUS);
        GRect r = new GRect(x0, top, CAR_WIDTH, CAR_HEIGHT);
        r.setFilled(true);
        r.setFillColor(color);
        add(r);
    }

    /*
     * This method draws the wheels.
     */
    private void drawWheel(double x, double y) {
        double r = WHEEL_RADIUS;
        GOval wheel = new GOval(x - r, y - r, 2 * r, 2 * r);
        wheel.setFilled(true);
        wheel.setFillColor(Color.GRAY);
        add(wheel);
    }

[Campbell Ritchie]

If you cast your Graphics object to Graphics2D, you can use the affine transform methods.

For example, scaling by -1.0 in the x-axis might give you a mirror image.

Beware: use the method which copies the Grahpics2D object before using affine transforms. Scale is probably all right, but you can get distortions using shear. Discard the copy after the transforms. I think the copy method is called create().

Moving to our GUIs forum, where we usually discuss such questions.