StreamGeometryContext.ArcTo 方法

  • 參考

定義

命名空間:
System.Windows.Media
組件:
PresentationCore.dll

繪製弧形至指定的點。

public:
 abstract void ArcTo(System::Windows::Point point, System::Windows::Size size, double rotationAngle, bool isLargeArc, System::Windows::Media::SweepDirection sweepDirection, bool isStroked, bool isSmoothJoin);
public abstract void ArcTo (System.Windows.Point point, System.Windows.Size size, double rotationAngle, bool isLargeArc, System.Windows.Media.SweepDirection sweepDirection, bool isStroked, bool isSmoothJoin);
abstract member ArcTo : System.Windows.Point * System.Windows.Size * double * bool * System.Windows.Media.SweepDirection * bool * bool -> unit
Public MustOverride Sub ArcTo (point As Point, size As Size, rotationAngle As Double, isLargeArc As Boolean, sweepDirection As SweepDirection, isStroked As Boolean, isSmoothJoin As Boolean)

參數

point
Point

弧形結尾的目的點。

size
Size

其圓周用來繪製角度之橢圓形的半徑 (寬度的一半和高度的一半)。 如果橢圓形會以所有方向四捨五入，則弧形會四捨五入，如果接近平面，則弧線也會四捨五入，因此弧線也會四捨五入。例如，非常大的寬度和高度代表非常大的橢圓形，這會為角度提供稍微的曲線。

rotationAngle
Double

指定曲線之橢圓形的旋轉角度。 而弧形曲率可以利用這個參數進行旋轉。

isLargeArc
Boolean

true 表示繪製大於 180 度的弧度，否則為 false。

sweepDirection
SweepDirection

值，表示是以 Clockwise 或 Counterclockwise 方向繪製弧形。

isStroked
Boolean

使用 Pen 轉譯區段，將區段劃上底線時，則為 true，否則為 false。

isSmoothJoin
Boolean

使用 Pen 畫底線時，將這個區段和前一個區段之間的這個聯結視為邊角，則為 true，否則為 false。

範例

下列範例示範如何使用 方法繪製弧線 ArcTo 。

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Shapes;

namespace SDKSample
{
    public partial class StreamGeometryArcToExample : Page
    {
        public StreamGeometryArcToExample()
        {
            // Create a path to draw a geometry with.
            Path myPath = new Path();
            myPath.Stroke = Brushes.Black;
            myPath.StrokeThickness = 1;

            // Create a StreamGeometry to use to specify myPath.
            StreamGeometry geometry = new StreamGeometry();
            geometry.FillRule = FillRule.EvenOdd;

            // Open a StreamGeometryContext that can be used to describe this StreamGeometry object's contents. 
            using (StreamGeometryContext ctx = geometry.Open())
            {
                // Set the begin point of the shape.
                ctx.BeginFigure(new Point(10, 100), true /* is filled */, false /* is closed */);

                // Create an arc. Draw the arc from the begin point to 200,100 with the specified parameters.
                ctx.ArcTo(new Point(200, 100), new Size(100, 50), 45 /* rotation angle */, true /* is large arc */, 
                          SweepDirection.Counterclockwise, true /* is stroked */, false /* is smooth join */);
            }

            // Freeze the geometry (make it unmodifiable)
            // for additional performance benefits.
            geometry.Freeze();
            
            // specify the shape (arc) of the path using the StreamGeometry.
            myPath.Data = geometry;

            // Add path shape to the UI.
            StackPanel mainPanel = new StackPanel();
            mainPanel.Children.Add(myPath);
            this.Content = mainPanel;
        }
    }
}


Imports System.Windows
Imports System.Windows.Controls
Imports System.Windows.Media
Imports System.Windows.Shapes

Namespace SDKSample
    Partial Public Class StreamGeometryArcToExample
        Inherits Page
        Public Sub New()
            ' Create a path to draw a geometry with.
            Dim myPath As New Path()
            myPath.Stroke = Brushes.Black
            myPath.StrokeThickness = 1

            ' Create a StreamGeometry to use to specify myPath.
            Dim geometry As New StreamGeometry()
            geometry.FillRule = FillRule.EvenOdd

            ' Open a StreamGeometryContext that can be used to describe this StreamGeometry object's contents. 
            Using ctx As StreamGeometryContext = geometry.Open()
                ' Set the begin point of the shape.
                ctx.BeginFigure(New Point(10, 100), True, False) ' is closed  -  is filled 

                ' Create an arc. Draw the arc from the begin point to 200,100 with the specified parameters.
                ctx.ArcTo(New Point(200, 100), New Size(100, 50), 45, True, SweepDirection.Counterclockwise, True, False) ' is smooth join  -  is stroked  -  is large arc  -  rotation angle 

            End Using

            ' Freeze the geometry (make it unmodifiable)
            ' for additional performance benefits.
            geometry.Freeze()

            ' specify the shape (arc) of the path using the StreamGeometry.
            myPath.Data = geometry

            ' Add path shape to the UI.
            Dim mainPanel As New StackPanel()
            mainPanel.Children.Add(myPath)
            Me.Content = mainPanel
        End Sub
    End Class
End Namespace

備註

這個方法會使用上一個區段的終點做為其起點。 如果這是圖中的第一個區段，它會使用 方法所 BeginFigure 指定的點做為其起點。

StreamGeometry如果它包含 Transform 或任何非筆劃或未填滿的區段，則無法序列化 。

適用於

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