xAxis height

[enumanc]

I would like to use xAxis in order to display a pole/stake on each side of the graphic but how to set an height to the xAxis if I want it lower than 100% of the real x axis ?
the width parameter exist but not the height (borderheight ?)
xaxis: [ { x: -5, strokeDashArray: 0, borderColor: '#000000', borderWidth: 5, offsetY: 0, label: { borderColor: '#000000', style: { color: '#fff', background: '#000000 ', }, text: 'Poteau_1', } },

[enumanc]

An update, I am talking about Annotation xAxis line :)