public Envelope tileBbox(int tx, int ty, int zoomLevel) {
        Coordinate topLeft = tileTopLeft(tx, ty, zoomLevel);
        // upperLeft of tx+1,ty+1 == lowRight
        Coordinate lowerRight = tileTopLeft(tx + 1, ty + 1, zoomLevel);
        Envelope result = new Envelope(topLeft, lowerRight);
        return result;
    }
public Envelope tileBbox ( int tx , int ty , int zoomLevel ) { Coordinate topLeft = tileTopLeft ( tx , ty , zoomLevel ) ; Coordinate lowerRight = tileTopLeft ( tx + 1 , ty + 1 , zoomLevel ) ; Envelope result = new Envelope ( topLeft , lowerRight ) ; return result ; }
Returns the EPSG:3857 bounding of the specified tile coordinate

@param tx        The tile x coordinate
@param ty        The tile y coordinate
@param zoomLevel The tile zoom level
@return the EPSG:3857 bounding box