DynamicRenderer.OnDraw Method

Reference

Definition

Namespace:: System.Windows.Input.StylusPlugIns

Assembly:: PresentationCore.dll

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Draws the ink in real-time so it appears to "flow" from the tablet pen or other pointing device.

protected:
 virtual void OnDraw(System::Windows::Media::DrawingContext ^ drawingContext, System::Windows::Input::StylusPointCollection ^ stylusPoints, System::Windows::Media::Geometry ^ geometry, System::Windows::Media::Brush ^ fillBrush);

protected virtual void OnDraw (System.Windows.Media.DrawingContext drawingContext, System.Windows.Input.StylusPointCollection stylusPoints, System.Windows.Media.Geometry geometry, System.Windows.Media.Brush fillBrush);

abstract member OnDraw : System.Windows.Media.DrawingContext * System.Windows.Input.StylusPointCollection * System.Windows.Media.Geometry * System.Windows.Media.Brush -> unit
override this.OnDraw : System.Windows.Media.DrawingContext * System.Windows.Input.StylusPointCollection * System.Windows.Media.Geometry * System.Windows.Media.Brush -> unit

Protected Overridable Sub OnDraw (drawingContext As DrawingContext, stylusPoints As StylusPointCollection, geometry As Geometry, fillBrush As Brush)

Parameters

drawingContext: DrawingContext

The DrawingContext object onto which the stroke is rendered.

stylusPoints: StylusPointCollection

The StylusPointCollection that represents the segment of the stroke to draw.

geometry: Geometry

A Geometry that represents the path of the mouse pointer.

fillBrush: Brush

A Brush that specifies the appearance of the current stroke.

Examples

The following example demonstrates how to override the OnDraw method to dynamically render digital ink with a LinearGradientBrush.

protected override void OnDraw(DrawingContext drawingContext,
                               StylusPointCollection stylusPoints,
                               Geometry geometry, Brush fillBrush)
{
    // Create a new Brush, if necessary
    if (brush == null)
    {
        Color primaryColor;

        if (fillBrush is SolidColorBrush)
        {
            primaryColor = ((SolidColorBrush)fillBrush).Color;
        }
        else
        {
            primaryColor = Colors.Red;
        }

        brush = new LinearGradientBrush(Colors.Blue, primaryColor, 20d);
    }

    drawingContext.DrawGeometry(brush, null, geometry);
}

Protected Overrides Sub OnDraw(ByVal drawingContext As DrawingContext, _
                               ByVal stylusPoints As StylusPointCollection, _
                               ByVal geometry As Geometry, _
                               ByVal fillBrush As Brush)

    ' Create a new Brush, if necessary
    If brush Is Nothing Then

        Dim primaryColor As Color

        If TypeOf fillBrush Is SolidColorBrush Then
            primaryColor = CType(fillBrush, SolidColorBrush).Color
        Else
            primaryColor = Colors.Red
        End If

        brush = New LinearGradientBrush(Colors.Blue, primaryColor, 20.0)

    End If

    drawingContext.DrawGeometry(brush, Nothing, geometry)

End Sub

Notes to Inheritors

When overriding OnDraw(DrawingContext, StylusPointCollection, Geometry, Brush) in a derived class, be sure to call the base class' OnDraw(DrawingContext, StylusPointCollection, Geometry, Brush) method.

Applies to

共用方式為