// normalize rotation

            rotation = (360.+(rotation%360.))%360.;

            int quadrant = (((int)rotation+45)/90)%4;

            double scaleX = 1.0, scaleY = 1.0;

            // scale to bounding box (bug #53176)

            if (quadrant == 1 || quadrant == 3) {

                // In quadrant 1 and 3, which is basically a shape in a more or less portrait orientation (45°-135° and 225°-315°),

                // we need to first rotate the shape by a multiple of 90° and then resize the bounding box  

                // to its original bbox. After that we can rotate the shape to the exact rotation amount.

                // It's strange that you'll need to rotate the shape back and forth again, but you can

                // think of it, as if you paint the shape on a canvas. First you rotate the canvas, which might

                // be already (differently) scaled, so you can paint the shape in its default orientation

                // and later on, turn it around again to compare it with its original size ...

                AffineTransform txg = new AffineTransform(); // graphics coordinate space

                AffineTransform txs = new AffineTransform(tx); // shape coordinate space

                txg.translate(centerX, centerY);

                txg.rotate(Math.toRadians(quadrant*90));

                txg.translate(-centerX, -centerY);

                txs.translate(centerX, centerY);

                txs.rotate(Math.toRadians(-quadrant*90));

                txs.translate(-centerX, -centerY);

                txg.concatenate(txs);

                Rectangle2D anchor2 = txg.createTransformedShape(getAnchor()).getBounds2D();

                scaleX = anchor.getWidth() == 0. ? 1.0 : anchor.getWidth() / anchor2.getWidth();

                scaleY = anchor.getHeight() == 0. ? 1.0 : anchor.getHeight() / anchor2.getHeight();

            }

            // transformation is applied reversed ...