The most common of all object in a Gantt chart is of course the activity bar (GanttBar()). In terms of formatting this object has a very large flexibility. The full signature for the GanttBar constructor is
 
 function 
GanttBar(
$aVPos,$aTitle,$aStart
,$aEnd,$aCaption,
$aHeight)
|   $aVPos 
 | The vertical position for the bar, [0..n] | |
|   $aTitle 
 | Title for the activity | |
|   $aStart 
 | Start date for the activity given as string, e.g "2001-09-22" | |
|   $aEnd  | End date for activity given as either a date (a string) or as the duration (in days) of the activity, e.g both "2001-10-15" and 20.5 are valid inputs | |
|   $aCaption 
 | Text string (caption) to appear at the end (right side) of the bar | |
|   $aHeight 
 | Height of bar given as either a value in range [0,1] in which case this is interpretated as what fraction of the vertical position should the bar occupy. The height can also be given in absolute pixels [1..200] |