C# 波浪线绘制

波浪线效果如上

界面绘制操作

     private Point? _startPoint = null;
     private void ContainerCanvas_OnPreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
     {
         var position = e.GetPosition(ContainerCanvas);
         if (_startPoint == null)
         {
             _startPoint = position;
         }
         else
         {
             //删除预览
             if (_previewLineElement != null)
             {
                 ContainerCanvas.Children.Remove(_previewLineElement);
                 _previewLineElement = null;
                 _lastMovedPoint = null;
             }
             //确定结束点，绘制波浪线
             var myLineElement = new MyLineElement();
             myLineElement.DrawLine((Point)_startPoint, position);
             ContainerCanvas.Children.Add(myLineElement);
             _startPoint = null;
         }
     }

     private MyLineElement _previewLineElement = null;
     private Point? _lastMovedPoint = null;

     /// <summary>
     /// 波浪线绘制预览
     /// </summary>
     /// <param name="sender"></param>
     /// <param name="e"></param>
     private void ContainerCanvas_OnMouseMove(object sender, MouseEventArgs e)
     {
         var position = e.GetPosition(ContainerCanvas);
         if (_startPoint != null && (_lastMovedPoint == null || _lastMovedPoint != null & (position - (Point)_lastMovedPoint).Length >= ))
         {
             _lastMovedPoint = position;
             if (_previewLineElement != null)
             {
                 ContainerCanvas.Children.Remove(_previewLineElement);
             }
             var myLineElement = new MyLineElement();
             myLineElement.DrawLine((Point)_startPoint, position);
             ContainerCanvas.Children.Add(myLineElement);
             _previewLineElement = myLineElement;
         }
     }

波浪线控件及绘制

     class MyLineElement : FrameworkElement
     {
         public MyLineElement()
         {
             _visualShape = new VisualCollection(this);
         }
         internal void DrawLine(Point startPoint, Point endPoint)
         {
             List<Point> points = ForgePoints(startPoint, endPoint);
             DrawLine(points);
         }
         private const int SeparatorPiexl = ;
         private const int AbundancePiexl = ;
         private List<Point> ForgePoints(Point startPoint, Point endPoint)
         {
             var points = new List<Point>();

             var lineVector = endPoint - startPoint;
             var lineDistance = lineVector.Length;
             var lineAngle = Math.Atan2(-(endPoint.Y - startPoint.Y), endPoint.X - startPoint.X);

             points.Add(startPoint);
             int index = ;
             bool isAbundanceUpward = true;
             while (index * SeparatorPiexl < lineDistance)
             {
                 index++;
                 //计算出间隔长度（模拟点到起始点）
                 var separatorDistance = index * SeparatorPiexl;
                 var abundancePiexl = AbundancePiexl;
                 var distanceToStartPoint = Math.Sqrt(Math.Pow(separatorDistance, ) + Math.Pow(abundancePiexl, ));
                 //计算出模拟点、起始点，与直线的角度
                 var separatorAngle = Math.Atan2(AbundancePiexl, separatorDistance);
                 separatorAngle = isAbundanceUpward ? separatorAngle : -separatorAngle;
                 isAbundanceUpward = !isAbundanceUpward;
                 //得到模拟点的水平角度
                 var mockPointAngle = lineAngle + separatorAngle;
                 //计算出模拟点坐标
                 var verticalDistance = distanceToStartPoint * Math.Sin(mockPointAngle);
                 var horizontalDistance = distanceToStartPoint * Math.Cos(mockPointAngle);
                 var mockPoint = new Point(startPoint.X + horizontalDistance, startPoint.Y - verticalDistance);
                 points.Add(mockPoint);
             }
             points.Add(endPoint);
             return points;
         }

         private void DrawLine(List<Point> points)
         {
             _visualShape.Clear();

             var geometryTest = new StreamGeometry();
             using (var ctx = geometryTest.Open())
             {
                 ctx.BeginFigure(points[], true, false);
                 if (points.Count %  == )
                 {
                     //绘制二阶贝塞尔函数，需要保证为偶数点
                     ctx.PolyQuadraticBezierTo(points, true, true);
                 }
                 else
                 {
                     //绘制二阶贝塞尔函数，需要保证为偶数点
                     points.Insert(, points[]);
                     ctx.PolyQuadraticBezierTo(points, true, true);
                 }

                 ctx.Close();
             }

             var visual = new DrawingVisual();
             using (var context = visual.RenderOpen())
             {
                 context.DrawGeometry(FillBrush, StrokePen, geometryTest);
             }
             _visualShape.Add(visual);
         }

         #region 内部方法

         [Obsolete]
         protected override void OnRender(DrawingContext drawingContext)
         {
             //弃用，改为_visualShape填充实现
             //drawingContext.DrawGeometry(FillBrush, StrokePen, BaseGeometry);
         }

         protected override int VisualChildrenCount => _visualShape.Count;

         protected override Visual GetVisualChild(int index)
         {
             if (index <  || index >= _visualShape.Count)
             {
                 throw new ArgumentOutOfRangeException();
             }

             return _visualShape[index];
         }

         #endregion

         #region 曲线属性

         private readonly VisualCollection _visualShape;
         protected Brush FillBrush { get; set; } = Brushes.Transparent;
         public Brush LineBrush { get; set; } = Brushes.DarkSeaGreen;
         protected double BorderThickness { get; set; } = 1.0;
         private Pen _defaultPen = null;
         protected Pen StrokePen
         {
             get
             {
                 if (_defaultPen == null)
                 {
                     _defaultPen = new Pen(LineBrush, BorderThickness);
                 }
                 return _defaultPen;
             }
             set => _defaultPen = value;
         }

         #endregion
     }

Github地址：https://github.com/Kybs0/WaveLineTextDemo