The Zoom method zooms the chart to ensure that interval StartDate and EndDate fits the chart's area. The Zoom method may change the Label, Unit, Count and the ToolTip properties for all levels in the chart. If the ChangeUnitWidth parameter is True, the Zoom method changes the UnitWidth property as necessary. Use the LevelCount property to specify the number of levels in the chart. Use the Level property to access the level in the chart area. Use the NextDate property to compute the next date based on a given unit. Use the NonworkingDaysPattern property on hide the nonworking days.

When zooming 

• the Label property takes a predefined value that's specified by the Label property of the Chart object. This way you can use the Label property of the Chart object to define the predefined formats for specified units. If the Label property for a specified unit is empty, the unit is ignored when zooming.
• the Unit property is changed accordingly with the Label property. For instance, if the Label property is set to "<%d%>", the Unit property is automatically put on exDay.
• the Count property is changed based on the available units ( the Label property is not empty )  and how large the interval is. 
• the ToolTip property is set on a predefined value that's specified by the LabelToolTip property, accordingly with the Unit property
• If the ChangeUnitWidth parameter is True, the UnitWidth property is changed if required. For instance, if we need to display a single week, that means that the PaneWidth property is divided in 7 pieces, and so the UnitWidth property is the PaneWidth / 7.

The following VB sample zooms the chart to display one week:

 With Gantt1.Chart
    .Label(exThirdMonth) = ""
    .Label(exDay) = "<%d%>/<%m%>"
    .Zoom .FirstVisibleDate, .NextDate(.FirstVisibleDate, exWeek), True
End With

The following C++ sample zooms the chart to display one week:

CChart chart = m_gantt.GetChart();
chart.SetLabel(17 /*exThirdMonth*/, "" );
chart.SetLabel(4096 /*exDay*/, "<%d%>/<%m%>" );
chart.Zoom( V2D( &chart.GetFirstVisibleDate() ), chart.GetNextDate( V2D( &chart.GetFirstVisibleDate() ), 256, COleVariant( (long)1 ) ), COleVariant( (long)TRUE ) );

The following VB.NET sample zooms the chart to display one week:

With AxGantt1.Chart
    .Label(EXGANTTLib.UnitEnum.exThirdMonth) = ""
    .Label(EXGANTTLib.UnitEnum.exDay) = "<%d%>/<%m%>"
    .Zoom(.FirstVisibleDate, .NextDate(.FirstVisibleDate, EXGANTTLib.UnitEnum.exWeek), True)
End With

The following C# sample zooms the chart to display one week:

EXGANTTLib.Chart chart = axGantt1.Chart;
chart.set_Label(EXGANTTLib.UnitEnum.exThirdMonth, "");
chart.set_Label(EXGANTTLib.UnitEnum.exDay, "<%d%>/<%m%>");
chart.Zoom(Convert.ToDateTime( chart.FirstVisibleDate ), chart.get_NextDate(Convert.ToDateTime(chart.FirstVisibleDate), EXGANTTLib.UnitEnum.exWeek, 1), true);

The following VFP sample zooms the chart to display one week:

With thisform.Gantt1.Chart
    .Label(17) = "" && exThirdMonth
    .Label(4096) = "<%d%>/<%m%>" && exDay
    .Zoom(.FirstVisibleDate, .NextDate(.FirstVisibleDate, 256), .t.) && exWeek
EndWith