David Qiao's Blog

final static double DEGREE_90 = 90.0 * Math.PI / 180.0;

    /**
     * Creates a rotated version of the input image.
     *
     * @param c            The component to get properties useful for painting, e.g. the foreground
     *                     or background color.
     * @param icon         the image to be rotated.
     * @param rotatedAngle the rotated angle, in degree, clockwise. It could be any double but we
     *                     will mod it with 360 before using it.
     *
     * @return the image after rotating.
     */
    public static ImageIcon createRotatedImage(Component c, Icon icon, double rotatedAngle) {
        // convert rotatedAngle to a value from 0 to 360
        double originalAngle = rotatedAngle % 360;
        if (rotatedAngle != 0 && originalAngle == 0) {
            originalAngle = 360.0;
        }

        // convert originalAngle to a value from 0 to 90
        double angle = originalAngle % 90;
        if (originalAngle != 0.0 && angle == 0.0) {
            angle = 90.0;
        }

        double radian = Math.toRadians(angle);

        int iw = icon.getIconWidth();
        int ih = icon.getIconHeight();
        int w;
        int h;

        if ((originalAngle >= 0 && originalAngle <= 90) || (originalAngle > 180 && originalAngle <= 270)) {
            w = (int) (iw * Math.sin(DEGREE_90 - radian) + ih * Math.sin(radian));
            h = (int) (iw * Math.sin(radian) + ih * Math.sin(DEGREE_90 - radian));
        }
        else {
            w = (int) (ih * Math.sin(DEGREE_90 - radian) + iw * Math.sin(radian));
            h = (int) (ih * Math.sin(radian) + iw * Math.sin(DEGREE_90 - radian));
        }
        BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_ARGB);
        Graphics g = image.getGraphics();
        Graphics2D g2d = (Graphics2D) g.create();

        // calculate the center of the icon.
        int cx = iw / 2;
        int cy = ih / 2;

        // move the graphics center point to the center of the icon.
        g2d.translate(w/2, h/2);

        // rotate the graphcis about the center point of the icon
        g2d.rotate(Math.toRadians(originalAngle));

        g2d.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BICUBIC);
        icon.paintIcon(c, g2d, -cx, -cy);

        g2d.dispose();
        return new ImageIcon(image);
    }