package stegsolve;

import java.awt.image.BufferedImage;

public class StereoTransform
{
  private BufferedImage originalImage;
  private BufferedImage transform;
  private int transNum;

  StereoTransform(BufferedImage bi)
  {
    this.originalImage = bi;
    this.transNum = 0;
    calcTrans();
  }

  private void calcTrans()
  {
    this.transform = new BufferedImage(this.originalImage.getWidth(), this.originalImage.getHeight(), 1);
    for (int i = 0; i < this.originalImage.getWidth(); i++) {
      for (int j = 0; j < this.originalImage.getHeight(); j++)
      {
        int col = 0;
        int fcol = this.originalImage.getRGB(i, j);
        col = fcol ^ this.originalImage.getRGB((i + this.transNum) % this.originalImage.getWidth(), j) & 0xFFFFFF;
        this.transform.setRGB(i, j, col);
      }
    }
  }

  public void back()
  {
    this.transNum -= 1;
    if (this.transNum < 0) {
      this.transNum = (this.originalImage.getWidth() - 1);
    }
    calcTrans();
  }

  public void forward()
  {
    this.transNum += 1;
    if (this.transNum >= this.originalImage.getWidth()) {
      this.transNum = 0;
    }
    calcTrans();
  }

  public String getText()
  {
    return "Offset: " + this.transNum;
  }

  public BufferedImage getImage()
  {
    return this.transform;
  }
}