StreamGeometryContext.QuadraticBezierTo 方法

  • 参考

定义

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

绘制一条二次贝塞尔曲线。

public:
 abstract void QuadraticBezierTo(System::Windows::Point point1, System::Windows::Point point2, bool isStroked, bool isSmoothJoin);
public abstract void QuadraticBezierTo (System.Windows.Point point1, System.Windows.Point point2, bool isStroked, bool isSmoothJoin);
abstract member QuadraticBezierTo : System.Windows.Point * System.Windows.Point * bool * bool -> unit
Public MustOverride Sub QuadraticBezierTo (point1 As Point, point2 As Point, isStroked As Boolean, isSmoothJoin As Boolean)

参数

point1
Point

用于指定曲线形状的控制点。

point2
Point

曲线末尾的目标点。

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。

例外

InvalidOperationException

试图添加一条线段，但未通过调用 BeginFigure(Point, Boolean, Boolean) 方法来指定图形的起点。

示例

以下示例演示如何使用 QuadraticBezierTo 该方法绘制二次贝塞尔曲线。

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

namespace SDKSample
{
    public partial class StreamGeometryQuadraticBezierToExample : Page
    {
        public StreamGeometryQuadraticBezierToExample()
        {
            // 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();

            // 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 a Quadratic Bezier curve using the 2 specifed points. The first point
                // specifies the control point while the second point specifies the end point 
                // of the curve.
                ctx.QuadraticBezierTo(new Point(100, 0), new Point(200, 200), true /* is stroked */, 
                                      false /* is smooth join */);
            }

            // Freeze the geometry (make it unmodifiable)
            // for additional performance benefits.
            geometry.Freeze();
            
            // specify the shape (quadratic Bezier curve) 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 StreamGeometryQuadraticBezierToExample
        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()

            ' 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 a Quadratic Bezier curve using the 2 specifed points. The first point
                ' specifies the control point while the second point specifies the end point 
                ' of the curve.
                ctx.QuadraticBezierTo(New Point(100, 0), New Point(200, 200), True, False) ' is smooth join  -  is stroked 

            End Using

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

            ' specify the shape (quadratic Bezier curve) 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

与使用两个控制点的立方贝塞尔曲线不同，二次立方贝塞尔曲线使用单个控制点。

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

如果它包含非Transform笔划或未填充段，则无法序列化 AStreamGeometry。

适用于

另请参阅