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package org.fit.pdfdom;

import java.awt.*;
import java.awt.geom.AffineTransform;
import java.awt.geom.Point2D;
import java.awt.image.AffineTransformOp;
import java.awt.image.BufferedImage;

class ImageUtils
{
    public static BufferedImage rotateImage(BufferedImage image, double theta)
    {
        int degrees = (int) Math.abs(Math.toDegrees(theta));
        double xCenter = image.getWidth() / 2;
        double yCenter = image.getHeight() / 2;
        AffineTransform rotateTransform = AffineTransform.getRotateInstance(-theta, xCenter, yCenter);

        // Translation adjustments so image still centered after rotate width/height changes
        if (image.getHeight() != image.getWidth() && degrees != 180 && degrees != 0)
        {
            Point2D origin = new Point2D.Double(0.0, 0.0);
            origin = rotateTransform.transform(origin, null);
            double yTranslate = origin.getY();

            Point2D yMax = new Point2D.Double(0, image.getHeight());
            yMax = rotateTransform.transform(yMax, null);
            double xTranslate = yMax.getX();

            AffineTransform translationAdjustment = AffineTransform.getTranslateInstance(-xTranslate, -yTranslate);
            rotateTransform.preConcatenate(translationAdjustment);
        }

        AffineTransformOp op = new AffineTransformOp(rotateTransform, AffineTransformOp.TYPE_BILINEAR);
        // Have to recopy image because of JDK bug #4723021, AffineTransformationOp throwing exception sometimes
        image = copyImage(image, BufferedImage.TYPE_INT_ARGB);

        // Need to create filter dest image ourselves since AffineTransformOp's own dest image creation
        // throws exceptions in some cases.
        Rectangle bounds = op.getBounds2D(image).getBounds();
        BufferedImage finalImage =
                new BufferedImage((int) bounds.getWidth(), (int) bounds.getHeight(), BufferedImage.TYPE_INT_ARGB);

        return op.filter(image, finalImage);
    }

    public static BufferedImage copyImage(BufferedImage source, int type)
    {
        BufferedImage copy = new BufferedImage(source.getWidth(), source.getHeight(), type);
        Graphics gfx = copy.getGraphics();
        gfx.drawImage(source, 0, 0, null);
        gfx.dispose();

        return copy;
    }


}