StreamGeometryContext.ArcTo 方法

  • 参考

定义

命名空间:
System.Windows.Media
程序集:
PresentationCore.dll

绘制一条到指定点的弧线。

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)

参数

point
Point

弧线末尾的目标点。

size
Size

其圆周用于绘制角度的椭圆的半径（半宽度和高度的一半）。 如果椭圆在各个方向上都非常四舍五入，则弧线将四舍五入，如果弧线几乎平整，则弧线也会四舍五入。例如，非常大的宽度和高度表示一个非常大的椭圆，这将为角度提供轻微的曲率。

rotationAngle
Double

指定曲线的椭圆的旋转角度。 可以使用此参数来旋转弧线的曲面。

isLargeArc
Boolean

若要绘制大于 180 度的弧线，则为 true；否则为 false。

sweepDirection
SweepDirection

一个值，该值指示在 Clockwise 还是 Counterclockwise 方向绘制弧线。

isStroked
Boolean

若要在使用 Pen 呈现线段时使线段描边，则为 true；否则为 false。

isSmoothJoin
Boolean

在用 Pen 描边时，如果要将此线段与前一条线段之间的联接视为角，则为 true；否则为 false。

示例

以下示例演示如何使用 ArcTo 方法绘制弧线。

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

注解

此方法使用上一段的终点作为其起点。 如果这是图中的第一段，则使用 方法指定的 BeginFigure 点作为起点。

StreamGeometry如果 包含 Transform 或任何非笔划段或未填充段，则无法序列化 。

适用于

另请参阅