Rotating Image in a PaintListener

For those who have a better understanding of matrices and 2-D graphics this may sound strange but today I struggeled about 2 hours rotating an image in a PaintListener.

Let me first of explain the exercise I had to solve, then show you my solution and then maybe someone can point out a better one.

Exercise

Draw an Image at Point(50,50) in a Canvas which is rotated a variable angle.

The solution

Solveing this problem one can use a SWT-Transform to adjust the Graphics-Context looks straight forward but it took me like said 2 hours to wrap my head around the problem. The following function is the solution I came up with.
public void paintControl(PaintEvent e) { GC gc = e.gc; gc.setAdvanced(true); Bounds b = image.getBounds(); Transform transform = new Transform(display); // The rotation point is the center of the image transform.translate(50 + b.width/2, 50 + b.height/2); // Rotate transform.rotate(45); // Back to the orginal coordinate system transform.translate(-50 - b.width/2, -50 - b.height/2); gc.setTransform(transform); gc.drawImage(image, 50, 50); transform.dispose(); } [/sourecode]

Is the solution right? Is there a better solution?

My skills are very very bad when it comes to matrices and 2-D graphics so the above solution to the problem might be completely wrong and only works by chance.