SetXTitle — Sets the X axis title, and optionally its position
$plot->SetXTitle($xtitle, [$xpos])
SetXTitle sets the text to be displayed as the X axis
title. Optionally, it also sets the position of the title and the axis
itself: below the graph (the usual place), above the graph, both, or
neither.
$xtitleThe text string to use for the X axis title. The string can contain multiple lines, separated by newlines (in PHP: "\n").
$xposOptional position for the X axis and title. Use one of the following strings for the position:
| Position | Description |
|---|---|
| plotdown | X axis below the plot |
| plotup | X axis above the plot |
| both | One X axis above, and one below |
| none | No X axis, no X axis title |
The default is 'plotdown'.