/**
   * Returns the specified property.
   *
   * @param name Property name.
   * @param opNode Operation node.
   */
  public Object getProperty(String name, Object opNode) {
    validate(name, opNode);

    if (opNode instanceof RenderedOp && name.equalsIgnoreCase("roi")) {
      RenderedOp op = (RenderedOp) opNode;

      ParameterBlock pb = op.getParameterBlock();

      // Retrieve the rendered source image and its ROI.
      RenderedImage src = pb.getRenderedSource(0);
      Object property = src.getProperty("ROI");
      if (property == null
          || property.equals(java.awt.Image.UndefinedProperty)
          || !(property instanceof ROI)) {
        return java.awt.Image.UndefinedProperty;
      }

      // Return undefined also if source ROI is empty.
      ROI srcROI = (ROI) property;
      if (srcROI.getBounds().isEmpty()) {
        return java.awt.Image.UndefinedProperty;
      }

      // Retrieve the Interpolation object.
      Interpolation interp = (Interpolation) pb.getObjectParameter(1);

      // Determine the effective source bounds.
      Rectangle srcBounds = null;
      PlanarImage dst = op.getRendering();
      if (dst instanceof GeometricOpImage && ((GeometricOpImage) dst).getBorderExtender() == null) {
        srcBounds =
            new Rectangle(
                src.getMinX() + interp.getLeftPadding(),
                src.getMinY() + interp.getTopPadding(),
                src.getWidth() - interp.getWidth() + 1,
                src.getHeight() - interp.getHeight() + 1);
      } else {
        srcBounds = new Rectangle(src.getMinX(), src.getMinY(), src.getWidth(), src.getHeight());
      }

      // If necessary, clip the ROI to the effective source bounds.
      if (!srcBounds.contains(srcROI.getBounds())) {
        srcROI = srcROI.intersect(new ROIShape(srcBounds));
      }

      // Retrieve the Warp object.
      Warp warp = (Warp) pb.getObjectParameter(0);

      // Setting constant image to be warped as a ROI
      Rectangle dstBounds = op.getBounds();

      // Setting layout of the constant image
      ImageLayout2 layout = new ImageLayout2();
      int minx = (int) srcBounds.getMinX();
      int miny = (int) srcBounds.getMinY();
      int w = (int) srcBounds.getWidth();
      int h = (int) srcBounds.getHeight();
      layout.setMinX(minx);
      layout.setMinY(miny);
      layout.setWidth(w);
      layout.setHeight(h);
      RenderingHints hints = op.getRenderingHints();
      hints.add(new RenderingHints(JAI.KEY_IMAGE_LAYOUT, layout));

      final PlanarImage constantImage =
          ConstantDescriptor.create(new Float(w), new Float(h), new Byte[] {(byte) 255}, hints);

      PlanarImage roiImage = null;

      // Make sure to specify tileCache, tileScheduler, tileRecyclier, by cloning hints.
      RenderingHints warpingHints = op.getRenderingHints();
      warpingHints.remove(JAI.KEY_IMAGE_LAYOUT);

      // Creating warped roi by the same way (Warp, Interpolation, source ROI) we warped the
      // input image.
      final ParameterBlock paramBlk = new ParameterBlock();
      paramBlk.addSource(constantImage);
      paramBlk.add(warp);
      paramBlk.add(interp);
      paramBlk.add(null);
      paramBlk.add(srcROI);

      // force in the image layout, this way we get exactly the same
      // as the affine we're eliminating
      Hints localHints = new Hints(op.getRenderingHints());
      localHints.remove(JAI.KEY_IMAGE_LAYOUT);
      ImageLayout il = new ImageLayout();
      il.setMinX(dstBounds.x);
      il.setMinY(dstBounds.y);
      il.setWidth(dstBounds.width);
      il.setHeight(dstBounds.height);
      localHints.put(JAI.KEY_IMAGE_LAYOUT, il);
      roiImage = JAI.create("Warp", paramBlk, localHints);
      ROI dstROI = new ROI(roiImage, 1);

      // If necessary, clip the warped ROI to the destination bounds.
      if (!dstBounds.contains(dstROI.getBounds())) {
        dstROI = dstROI.intersect(new ROIShape(dstBounds));
      }

      // Return the warped and possibly clipped ROI.
      return dstROI;
    }

    return java.awt.Image.UndefinedProperty;
  }