pChart 1.27d from http://pchart.sourceforge.net/ for PHP 7
// Parts like
$Plots = "";
$Plots[] = $X1;
$Plots[] = $Y1;
// 1st line has to be changed into
$Plots = array();
$Plots[] = $X1;
$Plots[] = $Y1;
Ressources:
- Stackoverflow
- PHP.net see "The empty index operator is not supported for strings anymore
Also see (seems to be more mature then my quick and dirty fix)
https://github.com/milkyway-git/pChart/commit/f330e9bbc1ec79234b646e42a916a4d4493ea90e