<UserControl x:Class="SLCurveSample.MainPage"xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"xmlns:d="http://schemas.microsoft.com/expression/blend/2008"xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"mc:Ignorable="d"d:DesignHeight="400" d:DesignWidth="400"><Canvas x:Name="LayoutRoot" Background="White"><Ellipse Width="10" Height="10" StrokeThickness="1" Stroke="Red" x:Name="point1"></Ellipse><TextBlock Text="Left Point" Name="tbLeftPoint" Visibility="Collapsed"></TextBlock><Ellipse Width="10" Height="10" StrokeThickness="1" Stroke="Red" x:Name="point2"></Ellipse><TextBlock Text="Right Point" Name="tbRightPoint" Visibility="Collapsed"></TextBlock><Path Stroke="Red" StrokeThickness="1" x:Name="p" ><Path.Data><PathGeometry><PathGeometry.Figures><PathFigure><PathFigure.Segments><BezierSegment />                              </PathFigure.Segments></PathFigure></PathGeometry.Figures></PathGeometry></Path.Data></Path></Canvas>
</UserControl>

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;namespace SLCurveSample
{public partial class MainPage : UserControl{Point _leftPoint = new Point();Point _rightPoint = new Point();BezierSegment seg = null;public MainPage(){InitializeComponent();this.Loaded += PageLoaded;}void PageLoaded(object sender, RoutedEventArgs e){this.SizeChanged += PageSizeChanged;this.MouseMove += PageMouseMove;this.Loaded -= PageLoaded;}void PageMouseMove(object sender, MouseEventArgs e){Point mousePos = e.GetPosition(this);//根据鼠标的位置对线条粗细、左右圈圈大小做一些交互double scale = Math.Abs(_leftPoint.Y - mousePos.Y) / _leftPoint.Y;point1.Width = point1.Height = 10 + 40 * scale;point2.Width = point2.Height = point1.Width;p.StrokeThickness = 3 - 2 * scale;//重绘Draw();//计算二个控制点的位置Point ctlPoint1 = new Point() { X = (mousePos.X + _leftPoint.X) * 0.5, Y = (mousePos.Y + _leftPoint.Y) * 0.5 };Point ctlPoint2 = new Point() { X = (mousePos.X + _rightPoint.X) * 0.5, Y = (mousePos.Y + _rightPoint.Y) * 0.5 };if (seg != null){seg.Point1 = ctlPoint1;//贝兹曲线的第一个控制点seg.Point2 = ctlPoint2;//贝兹曲线的第二个控制点}}void PageSizeChanged(object sender, SizeChangedEventArgs e){Draw();}void Draw(){double _stageWidth = this.ActualWidth;double _stageHeight = this.ActualHeight;double _margin = 80;//将二个小圈定位于左右二侧point1.SetValue(Canvas.TopProperty, _stageHeight * 0.5);point1.SetValue(Canvas.LeftProperty, _margin);point2.SetValue(Canvas.TopProperty, _stageHeight * 0.5);point2.SetValue(Canvas.LeftProperty, _stageWidth - _margin);//计算左侧小圈的中心_leftPoint.X = (double)point1.GetValue(Canvas.LeftProperty) + point1.Width * 0.5;_leftPoint.Y = (double)point1.GetValue(Canvas.TopProperty) + point1.Height * 0.5;tbLeftPoint.SetValue(Canvas.LeftProperty, _leftPoint.X - 20);tbLeftPoint.SetValue(Canvas.TopProperty, _leftPoint.Y + 10);//计算右侧小圈的中心_rightPoint.X = (double)point2.GetValue(Canvas.LeftProperty) + point2.Width * 0.5;_rightPoint.Y = (double)point2.GetValue(Canvas.TopProperty) + point2.Height * 0.5;tbRightPoint.SetValue(Canvas.LeftProperty, _rightPoint.X - 20);tbRightPoint.SetValue(Canvas.TopProperty, _rightPoint.Y + 10);PathFigure figure = (p.Data as PathGeometry).Figures[0];figure.StartPoint = _leftPoint;//设置(贝兹曲线的)起点seg = figure.Segments[0] as BezierSegment;seg.Point3 = _rightPoint;//贝兹曲线的终点}}
}