The IlvGanttChart class has an integrated grid mechanism that draws grids for the Gantt chart when the grapher views are being refreshed. Note that this grid mechanism exists only for grapher views. This integrated grid can be enabled or disabled by calling the method showGrid(). The grid is drawn by the method drawGrid(), which is a virtual method that can be overridden if the default implementation does not meet your needs. The grid drawing is invoked by IlvGanttGridViewHook(s) that are installed by default to all grapher views of the Gantt chart.

The integrated grids draw only when the grapher views of the Gantt chart is refreshed. Therefore, they cannot be dumped when you want to print the contents of the grapher. To resolve this problem, several grid classes are implemented as IlvGraphic objects and can be dumped with the contents of the associated grapher.

IlvGanttHorizontalGridImpl is an abstract class that implements the basic functions of the horizontal grids. It is designed to be subclassed to implement concrete grids. IlvGanttHorizontalGrid is the basic class for most of the grid classes.

IlvGanttLineGrid and IlvGanttLineReliefGrid are grids implemented for Gantt lines. Use the method IlvGanttChart::setLineGrid() to specify the grid to be used. The sample <ILVHOME>/samples/gantt/simple uses an IlvGanttLineReliefGrid.

IlvGanttResourceGrid is also a line grid but it is designed only for an IlvGanttChartForm. The sample <ILVHOME>/samples/gantt/calendar uses this grid.

Grids for Gantt rows are also provided. IlvGanttRowGrid is a grid designed for Gantt rows. Use the method IlvGanttChart::setRowGrid() to specify the grid to be used for Gantt rows. The sample <ILVHOME>/samples/gantt/simple uses this grid.

A special grid, IlvGanttCalendarGrid, is also provided for Gantt rows. This grid draws not only the horizontal grid for Gantt rows but also the vertical grid, which dynamically adjusts its graduation according to the current used zoom level. The sample <ILVHOME>/samples/gantt/calendar uses this grid.