DynamicRenderer.OnDraw 方法

定义

命名空间:

System.Windows.Input.StylusPlugIns

程序集:

PresentationCore.dll

墨迹的绘制是实时的，因此墨迹看起来就像从触笔或其他指针设备中“流”出来一样。

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)

参数

drawingContext

DrawingContext

在其上呈现笔画的 DrawingContext 对象。

stylusPoints

StylusPointCollection

StylusPointCollection，表示要绘制的笔画的线段。

geometry

Geometry

一个表示鼠标指针的路径的 Geometry。

fillBrush

Brush

一个指定当前笔画的外观的画笔。

示例

以下示例演示如何重写 OnDraw 方法以使用 a LinearGradientBrush动态呈现数字墨迹。

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

继承者说明

在派生类中重写 OnDraw(DrawingContext, StylusPointCollection, Geometry, Brush) 时，请务必调用基类 OnDraw(DrawingContext, StylusPointCollection, Geometry, Brush) 的方法。