Class ChartAnnotation

Serves as a base class for all types of annotations such as text, shape, and view. The annotations can be added to the chart.

Inheritance

System.Object

ChartAnnotation

ShapeAnnotation

TextAnnotation

ViewAnnotation

Namespace: Syncfusion.Maui.Charts

Assembly: Syncfusion.Maui.Charts.dll

Syntax

public abstract class ChartAnnotation : Element

Constructors

ChartAnnotation()

Declaration

public ChartAnnotation()

Fields

CoordinateUnitProperty

Identifies the CoordinateUnit bindable property.

Declaration

public static readonly BindableProperty CoordinateUnitProperty

Field Value

Type	Description
Microsoft.Maui.Controls.BindableProperty	The identifier for CoordinateUnit bindable property.

IsVisibleProperty

Identifies the IsVisible bindable property.

Declaration

public static readonly BindableProperty IsVisibleProperty

Field Value

Type	Description
Microsoft.Maui.Controls.BindableProperty	The identifier for IsVisible bindable property.

X1Property

Identifies the X1 bindable property.

Declaration

public static readonly BindableProperty X1Property

Field Value

Type	Description
Microsoft.Maui.Controls.BindableProperty	The identifier for X1 bindable property.

XAxisNameProperty

Identifies the XAxisName bindable property.

Declaration

public static readonly BindableProperty XAxisNameProperty

Field Value

Type	Description
Microsoft.Maui.Controls.BindableProperty	The identifier for XAxisName bindable property.

Y1Property

Identifies the Y1 bindable property.

Declaration

public static readonly BindableProperty Y1Property

Field Value

Type	Description
Microsoft.Maui.Controls.BindableProperty	The identifier for Y1 bindable property.

YAxisNameProperty

Identifies the YAxisName bindable property.

Declaration

public static readonly BindableProperty YAxisNameProperty

Field Value

Type	Description
Microsoft.Maui.Controls.BindableProperty	The identifier for YAxisName bindable property.

Properties

CoordinateUnit

Gets or sets the property that identifies whether the annotation is positioned based on pixel or axis coordinates.

Declaration

public ChartCoordinateUnit CoordinateUnit { get; set; }

Property Value

Type	Description
ChartCoordinateUnit	This property takes the ChartCoordinateUnit as its value. Its default value is Axis.

    <chart:SfCartesianChart>

    <!-- ... Eliminated for simplicity-->
    <chart:SfCartesianChart.Annotations>
         <chart:LineAnnotation X1="0" Y1="10" X2="4" Y2="50" CoordinateUnit="Axis"/>
    </chart:SfCartesianChart.Annotations>  

    </chart:SfCartesianChart>

    SfCartesianChart chart = new SfCartesianChart();     

    // Eliminated for simplicity
    var line = new LineAnnotation()
    {
        X1 = 0,
        Y1 = 10,
        X2 = 4,
        Y2 = 50,
       CoordinateUnit= ChartCoordinateUnit.Axis,
    };

    chart.Annotations.Add(line);

IsVisible

Gets or sets a value that indicates whether the annotation is visible or not.

Declaration

public bool IsVisible { get; set; }

Property Value

Type	Description
System.Boolean	This property takes the `bool` as its value. Its default value is true.

Examples

Xaml
C#

    <chart:SfCartesianChart>

    <!-- ... Eliminated for simplicity-->
    <chart:SfCartesianChart.Annotations>
         <chart:VerticalLineAnnotation X1="1" IsVisible="True"/>
    </chart:SfCartesianChart.Annotations>  

    </chart:SfCartesianChart>

    SfCartesianChart chart = new SfCartesianChart();     

    // Eliminated for simplicity
    var vertical = new VerticalLineAnnotation()
    {
        X1 = 1,
        IsVisible = true,
    };

    chart.Annotations.Add(vertical);

X1

Gets or sets the DateTime or double that represents the x1 position of the chart annotation.

Declaration

public object X1 { get; set; }

Property Value

Type	Description
System.Object	This property takes the `object` as its value. Its default value is null.

Examples

Xaml
C#

    <chart:SfCartesianChart>

    <!-- ... Eliminated for simplicity-->
    <chart:SfCartesianChart.Annotations>
         <chart:VerticalLineAnnotation X1="1"/>
    </chart:SfCartesianChart.Annotations>  

    </chart:SfCartesianChart>

    SfCartesianChart chart = new SfCartesianChart();     

    // Eliminated for simplicity
    var verticalLine = new VerticalLineAnnotation()
    {
        X1 = 1,
    };

    chart.Annotations.Add(verticalLine);

XAxisName

Get or set the value of a string that represents the name of the x-axis in the annotation.

Declaration

public string XAxisName { get; set; }

Property Value

Type	Description
System.String	This property takes the `string` as its value and its default value is string.Empty.

Examples

Xaml
C#

    <chart:SfCartesianChart>

    <!-- ... Eliminated for simplicity-->
    <chart:SfCartesianChart.Annotations>
         <chart:LineAnnotation X1="0" Y1="10" X2="4" Y2="50" LineCap="Arrow" XAxisName="xAxis"/>
    </chart:SfCartesianChart.Annotations>  

    </chart:SfCartesianChart>

    SfCartesianChart chart = new SfCartesianChart();     

    // Eliminated for simplicity
    var lineAnnotation = new LineAnnotation()
    {
        X1 = 0,
        Y1 = 10,
        X2 = 4,
        Y2 = 50,
        LineCap = ChartLineCap.Arrow,
        XAxisName= "xAxis",
    };

    chart.Annotations.Add(lineAnnotation);

Y1

Gets or sets the double that represents the y1 position of the chart annotation.

Declaration

public double Y1 { get; set; }

Property Value

Type	Description
System.Double	This property takes the `double` as its value and its default value is double.NaN.

Examples

Xaml
C#

    <chart:SfCartesianChart>

    <!-- ... Eliminated for simplicity-->
    <chart:SfCartesianChart.Annotations>
         <chart:HorizontalLineAnnotation Y1="10"/>
    </chart:SfCartesianChart.Annotations>  

    </chart:SfCartesianChart>

    SfCartesianChart chart = new SfCartesianChart();     

    // Eliminated for simplicity
    var horizontalAnnotation = new HorizontalLineAnnotation()
    {    
        Y1 = 10,        
    };

    chart.Annotations.Add(horizontalAnnotation);

YAxisName

Get or set the value of a string that represents the name of the y-axis in the annotation.

Declaration

public string YAxisName { get; set; }

Property Value

Type	Description
System.String	This property takes the `string` as its value and its default value is string.Empty.

Examples

Xaml
C#

    <chart:SfCartesianChart>

    <!-- ... Eliminated for simplicity-->
    <chart:SfCartesianChart.Annotations>
         <chart:LineAnnotation X1="0" Y1="10" X2="4" Y2="50" LineCap="Arrow" YAxisName="yAxis"/>
    </chart:SfCartesianChart.Annotations>  

    </chart:SfCartesianChart>

    SfCartesianChart chart = new SfCartesianChart();     

    // Eliminated for simplicity
    var line = new LineAnnotation()
    {
        X1 = 0,
        Y1 = 10,
        X2 = 4,
        Y2 = 50,
        LineCap = ChartLineCap.Arrow,
        YAxisName= "yAxis",
    };

    chart.Annotations.Add(line);

Methods

Draw(ICanvas, RectF)

Declaration

protected virtual void Draw(ICanvas canvas, RectF dirtyRect)

Parameters

Type	Name	Description
Microsoft.Maui.Graphics.ICanvas	canvas
Microsoft.Maui.Graphics.RectF	dirtyRect

OnTouchDown(Single, Single)

The method is called when a touch interaction begins on the ChartAnnotation.

Declaration

protected virtual void OnTouchDown(float pointX, float pointY)

Parameters

Type	Name	Description
System.Single	pointX
System.Single	pointY

Remarks

Use the provided points X and Y to determine the exact location of the touch.

OnTouchMove(Single, Single)

The method is called when touch movements occur over the ChartAnnotation.

Declaration

protected virtual void OnTouchMove(float pointX, float pointY)

Parameters

Type	Name	Description
System.Single	pointX
System.Single	pointY

Remarks

This method updates the annotation's position based on the current touch coordinates (X and Y).

OnTouchUp(Single, Single)

The method is called when the touch interaction with the ChartAnnotation ends.

Declaration

protected virtual void OnTouchUp(float pointX, float pointY)

Parameters

Type	Name	Description
System.Single	pointX
System.Single	pointY

Remarks

This method finalizes the annotation's position using the last known touch coordinates (X and Y).