code: public RenderOptions  viewPort(float minX, float minY, float width, float height)
     {
        this.viewPort = new SVG.Box(minX, minY, width, height);
        return this;
     }
docs: Describes the viewport into which the SVG should be rendered.  If this is not specified,
  then the whole of the canvas will be used as the viewport.  If rendering to a <code>Picture</code>
  then a default viewport width and height will be used.
  
  @param minX The left X coordinate of the viewport
  @param minY The top Y coordinate of the viewport
  @param width The width of the viewport
  @param height The height of the viewport
  @return this same <code>RenderOptions</code> instance