Hello, you can view any graphics from the ACP section Statistics and see the controller code. For example:
$chart = new \IPS\Helpers\Chart\Callback(
\IPS\Http\Url::internal( 'app=core&module=stats&controller=onlineusers' ),
array( $this, 'getResults' ),
'',
array(
'isStacked' => TRUE,
'backgroundColor' => '#ffffff',
'colors' => array( '#10967e', '#ea7963' ),
'hAxis' => array( 'gridlines' => array( 'color' => '#f5f5f5' ) ),
'lineWidth' => 1,
'areaOpacity' => 0.4
),
'AreaChart',
'none',
array( 'start' => \IPS\DateTime::ts( time() - ( 60 * 60 * 24 * 30 ) ), 'end' => \IPS\DateTime::create() ),
'',
$minimumDate
);