How to Change color of Bargraph
Set "varyBarColor" to true in renderOptions property. Here's an example of using varyBarColor (click on PHP Source tab):
http://phpchart.org/phpChart/examples/multiple_bar_colors.php
$pc->set_series_default(array(
'renderer'=>'plugin::BarRenderer',
'rendererOptions'=>array(
'
varyBarColor
'=>true),
'shadow'=>false));