code: protected BoundingBox padBoundingBox(TileMatrix tileMatrix,
  			BoundingBox boundingBox, int overlap) {
  		double lonPixelPadding = tileMatrix.getPixelXSize() * overlap;
  		double latPixelPadding = tileMatrix.getPixelYSize() * overlap;
  		BoundingBox paddedBoundingBox = new BoundingBox(
  				boundingBox.getMinLongitude() - lonPixelPadding,
  				boundingBox.getMinLatitude() - latPixelPadding,
  				boundingBox.getMaxLongitude() + lonPixelPadding,
  				boundingBox.getMaxLatitude() + latPixelPadding);
  		return paddedBoundingBox;
  	}
docs: Pad the bounding box with extra space for the overlapping pixels
  
  @param tileMatrix
  tile matrix
  @param boundingBox
  bounding box
  @param overlap
  overlapping pixels
  @return padded bounding box