             var start = api.coord([api.value(0), yValue]);
                    var size = api.size([api.value(1) - api.value(0), yValue]);
                    var style = api.style();

                    return {
                        type: 'rect',
                        shape: {
                            x: start[0] + 1,
                            y: start[1],
                            width: size[0] - 2,
                            height: size[1]
                        },
                     