語言

StreamGeometryContext.ArcTo 方法

定義

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

畫出一條弧線到指定點。

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

這是弧線結束的終點。

size
Size

橢圓的半徑（寬度與高度的一半）用來繪製角度。 如果橢圓在各個方向都非常圓潤，弧線也會圓潤;如果幾乎平坦，則圓弧也會圓潤。例如，非常大的寬度和高度代表一個非常大的橢圓形，這會讓角度稍微彎曲。

rotationAngle
Double

指定曲線的橢圓旋轉角度。 弧的曲率可以用此參數旋轉。

isLargeArc
Boolean

true畫出超過180度的弧線;否則，。 false

sweepDirection
SweepDirection

一個表示弧線是否朝 Clockwise 或 Counterclockwise 方向繪製的值。

isStroked
Boolean

true當使用 a Pen 來渲染該段時，使該段被描繪;否則，。 false

isSmoothJoin
Boolean

true當用 Pena 描繪時，將此段與前一段段的連接視為角點;否則，。 false

範例

以下範例展示了如何使用此 ArcTo 方法繪製弧線。

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

此方法以前一段的終點作為起點。 如果這是圖中的第一個段，則以該方法指定的 BeginFigure 點作為起點。

若 A StreamGeometry 包含 a Transform 或任何非劃線或未填充的區段，則無法序列化。

適用於

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