add_popup (SVG::Graph::Graph)

    # File temp/Graph/Graph.rb, line 413
          def add_popup( x, y, label )
            txt_width = label.length * font_size * 0.6 + 10
            tx = (x+txt_width > width ? x-5 : x+5)
            t = @foreground.add_element( "text", {
              "x" => tx.to_s,
              "y" => (y - font_size).to_s,
              "visibility" => "hidden",
            })
            t.attributes["style"] = "fill: #000; "+
              (x+txt_width > width ? "text-anchor: end;" : "text-anchor: start;")
            t.text = label.to_s
            t.attributes["id"] = t.object_id.to_s

            @foreground.add_element( "circle", {
              "cx" => x.to_s,
              "cy" => y.to_s,
              "r" => "10",
              "style" => "opacity: 0",
              "onmouseover" =>
                "document.getElementById(#{t.object_id}).setAttribute('visibility', 'visible' )",
              "onmouseout" =>
                "document.getElementById(#{t.object_id}).setAttribute('visibility', 'hidden' )",
            })

          end