Zooming functionality in Blazor Gantt Chart component

4 Nov 202517 minutes to read

The Blazor Gantt Chart component provides zooming support to adjust the timeline view dynamically. This includes increasing or decreasing the width of timeline cells and changing the timeline units to view tasks across various timespan from minutes to decades.

To enable zooming features, add ZoomIn, ZoomOut, and ZoomToFit to the toolbar items collection. These actions can also be triggered externally using the built-in methods like ZoomIn, ZoomOut, and ZoomToFitAsync.

Zoom in

This support is used to increase the timeline width and timeline unit from years to minutes timespan. When the ZoomIn icon was clicked, the timeline cell width is increased when the cell size exceeds the specified range and the timeline unit is changed based on the current zoom levels.

Zoom out

This support is used to increase the timeline width and timeline unit from minutes to years timespan. When the ZoomOut icon was clicked, the timeline cell width is decreased when the cell size falls behind the specified range and the timeline view mode is changed based on the current zooming levels.

Zoom to fit

This support is used to view all the tasks available in a project within available area on the chart part of Gantt. When users click the ZoomToFit icon, then all the tasks are rendered within the available chart container width.

Index.razor
@using Syncfusion.Blazor.Gantt
<SfGantt DataSource="@TaskCollection" Toolbar="@(new List<string>() { "ZoomIn", "ZoomOut", "ZoomToFit" })" Height="450px" Width="700px">
    <GanttTaskFields Id="TaskID" Name="TaskName" StartDate="StartDate" EndDate="EndDate" Duration="Duration" Progress="Progress" ParentID="ParentID" Dependency="Predecessor">
    </GanttTaskFields>
    <GanttLabelSettings LeftLabel="TaskName" TValue="TaskData"></GanttLabelSettings>
</SfGantt>

@code{
    private List<TaskData> TaskCollection { get; set; }
    protected override void OnInitialized()
    {
        this.TaskCollection = GetTaskCollection();
    }

    public class TaskData
    {
        public int TaskID { get; set; }
        public string TaskName { get; set; }
        public DateTime StartDate { get; set; }
        public DateTime EndDate { get; set; }
        public string Duration { get; set; }
        public int Progress { get; set; }
        public string Predecessor { get; set; }
        public int? ParentID { get; set; }
    }

    public static List<TaskData> GetTaskCollection()
    {
        List<TaskData> Tasks = new List<TaskData>()
        {
            new TaskData() { TaskID = 1, TaskName = "Project initiation", StartDate = new DateTime(2022, 04, 05), EndDate = new DateTime(2022, 04, 21), },
            new TaskData() { TaskID = 2, TaskName = "Identify Site location", StartDate = new DateTime(2022, 04, 05), Duration = "0", Progress = 30, ParentID = 1 },
            new TaskData() { TaskID = 3, TaskName = "Perform soil test", StartDate = new DateTime(2022, 04, 05), Duration = "4", Progress = 40, Predecessor = "2", ParentID = 1 },
            new TaskData() { TaskID = 4, TaskName = "Soil test approval", StartDate = new DateTime(2022, 04, 05), Duration = "0", Progress = 30, Predecessor = "3", ParentID = 1 },
            new TaskData() { TaskID = 5, TaskName = "Project estimation", StartDate = new DateTime(2022, 04, 06), EndDate = new DateTime(2022, 04, 21), },
            new TaskData() { TaskID = 6, TaskName = "Develop floor plan for estimation", StartDate = new DateTime(2022, 04, 06), Duration = "3", Progress = 30, Predecessor = "4", ParentID = 5 },
            new TaskData() { TaskID = 7, TaskName = "List materials", StartDate = new DateTime(2022, 04, 06), Duration = "3", Progress = 40, Predecessor = "6", ParentID = 5 },
            new TaskData() { TaskID = 8, TaskName = "Estimation approval", StartDate = new DateTime(2022, 04, 06), Duration = "0", Progress = 30, Predecessor = "7", ParentID = 5 },
        };
        return Tasks;
    }
}

Customizing zooming levels

Zoom actions are governed by predefined zooming levels specified in the CustomZoomingLevels property. These levels can be customized by assigning a collection of zoom configurations to the CustomZoomingLevels property.

Index.razor
@using Syncfusion.Blazor.Gantt
<SfGantt @ref="Gantt" DataSource="@TaskCollection" CustomZoomingLevels=zoomingLevel Toolbar="@(new List<string>() { "ZoomIn", "ZoomOut", "ZoomToFit" })" Height="450px" Width="700px">
    <GanttTaskFields Id="TaskID" Name="TaskName" StartDate="StartDate" EndDate="EndDate" Duration="Duration" Progress="Progress" ParentID="ParentID" Dependency="Predecessor">
    </GanttTaskFields>
</SfGantt>

@code{
    private GanttZoomTimelineSettings[] zoomingLevel = new GanttZoomTimelineSettings[]
    {
            new GanttZoomTimelineSettings { TopTier = new GanttTopTierSettings { Unit = TimelineViewMode.Month, Format = "MMM yyyy", Count = 1 }, BottomTier = new GanttBottomTierSettings { Unit = TimelineViewMode.Week, Format = "MMM yy", Count = 1 }, TimelineUnitSize = 66, TimelineViewMode = TimelineViewMode.Month, WeekStartDay = 0, UpdateTimescaleView = true, WeekendBackground = null, ShowTooltip = true, Level = 0 },
            new GanttZoomTimelineSettings { TopTier = new GanttTopTierSettings { Unit = TimelineViewMode.Month, Format = "MMM yyyy", Count = 1 }, BottomTier = new GanttBottomTierSettings { Unit = TimelineViewMode.Week, Format = "dd MMM", Count = 1}, TimelineUnitSize = 99, TimelineViewMode = TimelineViewMode.Month, WeekStartDay = 0, UpdateTimescaleView = true, WeekendBackground = null, ShowTooltip = true, Level = 1 },
            new GanttZoomTimelineSettings { TopTier = new GanttTopTierSettings { Unit = TimelineViewMode.Week, Format = "MMM dd yyyy", Count = 1 }, BottomTier = new GanttBottomTierSettings { Unit = TimelineViewMode.Day, Format = "dd", Count = 1 }, TimelineUnitSize = 33, TimelineViewMode = TimelineViewMode.Month, WeekStartDay = 0, UpdateTimescaleView = true, WeekendBackground = null, ShowTooltip = true, Level = 2 },
            new GanttZoomTimelineSettings { TopTier = new GanttTopTierSettings { Unit = TimelineViewMode.Week, Format = "MMM dd yyyy", Count = 1 }, BottomTier = new GanttBottomTierSettings { Unit = TimelineViewMode.Day, Format = "dd", Count = 1 }, TimelineUnitSize = 66, TimelineViewMode = TimelineViewMode.Week, WeekStartDay = 0, UpdateTimescaleView = true, WeekendBackground = null, ShowTooltip = true, Level = 3 },
            new GanttZoomTimelineSettings { TopTier = new GanttTopTierSettings { Unit = TimelineViewMode.Week, Format = "MMM dd yyyy", Count = 1 }, BottomTier = new GanttBottomTierSettings { Unit = TimelineViewMode.Day, Format = "dd", Count = 1 }, TimelineUnitSize = 99, TimelineViewMode = TimelineViewMode.Week, WeekStartDay = 0, UpdateTimescaleView = true, WeekendBackground = null, ShowTooltip = true, Level = 4 },
            new GanttZoomTimelineSettings { TopTier = new GanttTopTierSettings { Unit = TimelineViewMode.Day, Format = "MMM dd yyyy", Count = 1 }, BottomTier = new GanttBottomTierSettings { Unit = TimelineViewMode.Hour, Format = "hh tt", Count = 12 }, TimelineUnitSize = 66, TimelineViewMode = TimelineViewMode.Day, WeekStartDay = 0, UpdateTimescaleView = true, WeekendBackground = null, ShowTooltip = true, Level = 5 },
            new GanttZoomTimelineSettings { TopTier = new GanttTopTierSettings { Unit = TimelineViewMode.Day, Format = "MMM dd yyyy", Count = 1 }, BottomTier = new GanttBottomTierSettings { Unit = TimelineViewMode.Hour, Format = "hh tt", Count = 6 }, TimelineUnitSize = 99, TimelineViewMode = TimelineViewMode.Day, WeekStartDay = 0, UpdateTimescaleView = true, WeekendBackground = null, ShowTooltip = true, Level = 6 },
    };
    private SfGantt<TaskData> Gantt;
    private List<TaskData> TaskCollection { get; set; }
    protected override void OnInitialized()
    {
        this.TaskCollection = GetTaskCollection();
    }

    public class TaskData
    {
        public int TaskID { get; set; }
        public string TaskName { get; set; }
        public DateTime StartDate { get; set; }
        public DateTime EndDate { get; set; }
        public string Duration { get; set; }
        public int Progress { get; set; }
        public string Predecessor { get; set; }
        public int? ParentID { get; set; }
    }

    public static List<TaskData> GetTaskCollection()
    {
        List<TaskData> Tasks = new List<TaskData>()
        {
            new TaskData() { TaskID = 1, TaskName = "Project initiation", StartDate = new DateTime(2022, 04, 05), EndDate = new DateTime(2022, 04, 08), },
            new TaskData() { TaskID = 2, TaskName = "Identify Site location", StartDate = new DateTime(2022, 04, 05), Duration = "0", Progress = 30, ParentID = 1 },
            new TaskData() { TaskID = 3, TaskName = "Perform soil test", StartDate = new DateTime(2022, 04, 05), Duration = "4", Progress = 40, Predecessor = "2", ParentID = 1 },
            new TaskData() { TaskID = 4, TaskName = "Soil test approval", StartDate = new DateTime(2022, 04, 05), Duration = "0", Progress = 30, Predecessor = "3", ParentID = 1 },
            new TaskData() { TaskID = 5, TaskName = "Project estimation", StartDate = new DateTime(2022, 04, 11), EndDate = new DateTime(2022, 04, 18), },
            new TaskData() { TaskID = 6, TaskName = "Develop floor plan for estimation", StartDate = new DateTime(2022, 04, 06), Duration = "3", Progress = 30, Predecessor = "4", ParentID = 5 },
            new TaskData() { TaskID = 7, TaskName = "List materials", StartDate = new DateTime(2022, 04, 06), Duration = "3", Progress = 40, Predecessor = "6", ParentID = 5 },
            new TaskData() { TaskID = 8, TaskName = "Estimation approval", StartDate = new DateTime(2022, 04, 06), Duration = "0", Progress = 30, Predecessor = "7", ParentID = 5 },
        };
        return Tasks;
    }
}

Zoom actions via methods

Zooming actions can be triggered dynamically or through external controls using the following methods:

Zoom In - Use ZoomIn when ZoomIn external button was clicked, the timeline cell width is increased when the cell size exceeds the specified range and the timeline unit is changed based on the current zoom levels.
Zoom Out - Use ZoomOut when the ZoomOut external button was clicked, the timeline cell width is decreased when the cell size falls behind the specified range and the timeline view mode is changed based on the current zooming levels.
Zoom To Fit - Use ZoomToFitAsync When Fit To Project external button was clicked then all the tasks are rendered within the available chart container width.

Index.razor
@using Syncfusion.Blazor.Gantt

<button @onclick="ZoomIn">Zoom In</button>
<button @onclick="ZoomOut">Zoom Out</button>
<button @onclick="ZoomToFit">Fit To Project</button>

<SfGantt @ref="Gantt" DataSource="@TaskCollection" Height="450px" Width="700px">
    <GanttTaskFields Id="TaskID" Name="TaskName" StartDate="StartDate" EndDate="EndDate" Duration="Duration" Progress="Progress" ParentID="ParentID" Dependency="Predecessor">
    </GanttTaskFields>
    <GanttLabelSettings LeftLabel="TaskName" TValue="TaskData"></GanttLabelSettings>
</SfGantt>

@code {
    private SfGantt<TaskData> Gantt;
    private List<TaskData> TaskCollection { get; set; }
    protected override void OnInitialized()
    {
        this.TaskCollection = GetTaskCollection();
    }
    private async void ZoomIn()
    {
        await Gantt.ZoomInAsync();
    }
    private async void ZoomOut()
    {
        await Gantt.ZoomOutAsync();
    }
    private async void ZoomToFit()
    {
        await Gantt.ZoomToFitAsync();
    }
    public class TaskData
    {
        public int TaskID { get; set; }
        public string TaskName { get; set; }
        public DateTime StartDate { get; set; }
        public DateTime EndDate { get; set; }
        public string Duration { get; set; }
        public int Progress { get; set; }
        public string Predecessor { get; set; }
        public int? ParentID { get; set; }
    }

    public static List<TaskData> GetTaskCollection()
    {
        List<TaskData> Tasks = new List<TaskData>()
        {
            new TaskData() { TaskID = 1, TaskName = "Project initiation", StartDate = new DateTime(2022, 04, 05), EndDate = new DateTime(2022, 04, 21), },
            new TaskData() { TaskID = 2, TaskName = "Identify Site location", StartDate = new DateTime(2022, 04, 05), Duration = "0", Progress = 30, ParentID = 1 },
            new TaskData() { TaskID = 3, TaskName = "Perform soil test", StartDate = new DateTime(2022, 04, 05), Duration = "4", Progress = 40, Predecessor = "2", ParentID = 1 },
            new TaskData() { TaskID = 4, TaskName = "Soil test approval", StartDate = new DateTime(2022, 04, 05), Duration = "0", Progress = 30, Predecessor = "3", ParentID = 1 },
            new TaskData() { TaskID = 5, TaskName = "Project estimation", StartDate = new DateTime(2022, 04, 06), EndDate = new DateTime(2022, 04, 21), },
            new TaskData() { TaskID = 6, TaskName = "Develop floor plan for estimation", StartDate = new DateTime(2022, 04, 06), Duration = "3", Progress = 30, Predecessor = "4", ParentID = 5 },
            new TaskData() { TaskID = 7, TaskName = "List materials", StartDate = new DateTime(2022, 04, 06), Duration = "3", Progress = 40, Predecessor = "6", ParentID = 5 },
            new TaskData() { TaskID = 8, TaskName = "Estimation approval", StartDate = new DateTime(2022, 04, 06), Duration = "0", Progress = 30, Predecessor = "7", ParentID = 5 },
        };
        return Tasks;
    }
}

Resetting zooming levels using method

In Gantt chart, you can reset the zoom level to its initial state, as configured during the initial rendering, after performing zooming actions like ZoomIn, ZoomOut, and ZoomToFit, using ResetZoomAsync method.

Index.razor
@using Syncfusion.Blazor.Gantt

<button @onclick="ResetZoomingLevels">Reset Zoom</button>

<SfGantt @ref="Gantt" DataSource="@TaskCollection" Toolbar="@(new List<string>() { "ZoomIn", "ZoomOut", "ZoomToFit" })" Height="450px" Width="700px">
    <GanttTaskFields Id="TaskID" Name="TaskName" StartDate="StartDate" EndDate="EndDate" Duration="Duration" Progress="Progress" ParentID="ParentID" Dependency="Predecessor">
    </GanttTaskFields>
    <GanttLabelSettings LeftLabel="TaskName" TValue="TaskData"></GanttLabelSettings>
</SfGantt>

@code {
    private SfGantt<TaskData> Gantt;
    private List<TaskData> TaskCollection { get; set; }
    protected override void OnInitialized()
    {
        this.TaskCollection = GetTaskCollection();
    }
    private async void ResetZoomingLevels()
    {
        await Gantt.ResetZoomAsync();
    }
    public class TaskData
    {
        public int TaskID { get; set; }
        public string TaskName { get; set; }
        public DateTime StartDate { get; set; }
        public DateTime EndDate { get; set; }
        public string Duration { get; set; }
        public int Progress { get; set; }
        public string Predecessor { get; set; }
        public int? ParentID { get; set; }
    }

    public static List<TaskData> GetTaskCollection()
    {
        List<TaskData> Tasks = new List<TaskData>()
        {
            new TaskData() { TaskID = 1, TaskName = "Project initiation", StartDate = new DateTime(2022, 04, 05), EndDate = new DateTime(2022, 04, 08), },
            new TaskData() { TaskID = 2, TaskName = "Identify Site location", StartDate = new DateTime(2022, 04, 05), Duration = "0", Progress = 30, ParentID = 1 },
            new TaskData() { TaskID = 3, TaskName = "Perform soil test", StartDate = new DateTime(2022, 04, 05), Duration = "4", Progress = 40, Predecessor = "2", ParentID = 1 },
            new TaskData() { TaskID = 4, TaskName = "Soil test approval", StartDate = new DateTime(2022, 04, 05), Duration = "0", Progress = 30, Predecessor = "3", ParentID = 1 },
            new TaskData() { TaskID = 5, TaskName = "Project estimation", StartDate = new DateTime(2022, 04, 11), EndDate = new DateTime(2022, 04, 18), },
            new TaskData() { TaskID = 6, TaskName = "Develop floor plan for estimation", StartDate = new DateTime(2022, 04, 06), Duration = "3", Progress = 30, Predecessor = "4", ParentID = 5 },
            new TaskData() { TaskID = 7, TaskName = "List materials", StartDate = new DateTime(2022, 04, 06), Duration = "3", Progress = 40, Predecessor = "6", ParentID = 5 },
            new TaskData() { TaskID = 8, TaskName = "Estimation approval", StartDate = new DateTime(2022, 04, 06), Duration = "0", Progress = 30, Predecessor = "7", ParentID = 5 },
        };
        return Tasks;
    }
}

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