語言

DynamicRenderer.OnDraw 方法

定義

命名空間:
System.Windows.Input.StylusPlugIns
組件:
PresentationCore.dll

即時繪製墨水，讓墨水看起來像是從繪圖筆或其他指點裝置「流動」出來的。

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)

參數

drawingContext
DrawingContext

筆 DrawingContext 劃所渲染的物件。

stylusPoints
StylusPointCollection

那 StylusPointCollection 代表要畫的筆劃段。

geometry
Geometry

A Geometry 代表滑鼠指標的路徑。

fillBrush
Brush

一把筆刷，用來指定當前筆劃的外觀。

範例

以下範例示範如何覆寫 OnDraw 以 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

給繼承者的注意事項

在導出類別中覆 OnDraw(DrawingContext, StylusPointCollection, Geometry, Brush) 寫時，務必呼叫基底類別的方法 OnDraw(DrawingContext, StylusPointCollection, Geometry, Brush) 。

適用於