C# 波浪线绘制

             1
            private Point? _startPoint = null;
 2privatevoid ContainerCanvas_OnPreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
 3    {
 4var position = e.GetPosition(ContainerCanvas);
 5if (_startPoint == null)
 6        {
 7             _startPoint = position;
 8        }
 9else10        {
11//删除预览12if (_previewLineElement != null)
13            {
14                ContainerCanvas.Children.Remove(_previewLineElement);
15                 _previewLineElement = null;
16                 _lastMovedPoint = null;
17            }
18//确定结束点，绘制波浪线19var myLineElement = new MyLineElement();
20            myLineElement.DrawLine((Point)_startPoint, position);
21            ContainerCanvas.Children.Add(myLineElement);
22             _startPoint = null;
23        }
24    }
2526private MyLineElement _previewLineElement = null;
27private Point? _lastMovedPoint = null;
2829///<summary>30/// 波浪线绘制预览
31///</summary>32///<param name="sender"></param>33///<param name="e"></param>34privatevoid ContainerCanvas_OnMouseMove(object sender, MouseEventArgs e)
35    {
36var position = e.GetPosition(ContainerCanvas);
37if (_startPoint != null && (_lastMovedPoint == null || _lastMovedPoint != null & (position - (Point)_lastMovedPoint).Length >= 2))
38        {
39             _lastMovedPoint = position;
40if (_previewLineElement != null)
41            {
42                ContainerCanvas.Children.Remove(_previewLineElement);
43            }
44var myLineElement = new MyLineElement();
45            myLineElement.DrawLine((Point)_startPoint, position);
46            ContainerCanvas.Children.Add(myLineElement);
47             _previewLineElement = myLineElement;
48        }
49     }

              1
            class
             MyLineElement : FrameworkElement

              2
                {

              3
            public
             MyLineElement()

              4
                    {

              5             _visualShape = new VisualCollection(this);
  6        }
  7internalvoid DrawLine(Point startPoint, Point endPoint)
  8        {
  9             List<Point> points = ForgePoints(startPoint, endPoint);
 10            DrawLine(points);
 11        }
 12privateconstint SeparatorPiexl = 4;
 13privateconstint AbundancePiexl = 3;
 14private List<Point> ForgePoints(Point startPoint, Point endPoint)
 15        {
 16var points = new List<Point>();
 17 18var lineVector = endPoint - startPoint;
 19var lineDistance = lineVector.Length;
 20var lineAngle = Math.Atan2(-(endPoint.Y - startPoint.Y), endPoint.X - startPoint.X);
 21 22            points.Add(startPoint);
 23int index = 0;
 24bool isAbundanceUpward = true;
 25while (index * SeparatorPiexl < lineDistance)
 26            {
 27                 index++;
 28//计算出间隔长度（模拟点到起始点） 29var separatorDistance = index * SeparatorPiexl;
 30var abundancePiexl = AbundancePiexl;
 31var distanceToStartPoint = Math.Sqrt(Math.Pow(separatorDistance, 2) + Math.Pow(abundancePiexl, 2));
 32//计算出模拟点、起始点，与直线的角度 33var separatorAngle = Math.Atan2(AbundancePiexl, separatorDistance);
 34                 separatorAngle = isAbundanceUpward ? separatorAngle : -separatorAngle;
 35                 isAbundanceUpward = !isAbundanceUpward;
 36//得到模拟点的水平角度 37var mockPointAngle = lineAngle + separatorAngle;
 38//计算出模拟点坐标 39var verticalDistance = distanceToStartPoint * Math.Sin(mockPointAngle);
 40var horizontalDistance = distanceToStartPoint * Math.Cos(mockPointAngle);
 41var mockPoint = new Point(startPoint.X + horizontalDistance, startPoint.Y - verticalDistance);
 42                points.Add(mockPoint);
 43            }
 44            points.Add(endPoint);
 45return points;
 46        }
 47 48privatevoid DrawLine(List<Point> points)
 49        {
 50            _visualShape.Clear();
 51 52var geometryTest = new StreamGeometry();
 53using (var ctx = geometryTest.Open())
 54            {
 55                 ctx.BeginFigure(points[0], true, false);
 56if (points.Count % 2 == 0)
 57                {
 58//绘制二阶贝塞尔函数，需要保证为偶数点 59                     ctx.PolyQuadraticBezierTo(points, true, true);
 60                }
 61else 62                {
 63//绘制二阶贝塞尔函数，需要保证为偶数点 64                     points.Insert(0, points[0]);
 65                     ctx.PolyQuadraticBezierTo(points, true, true);
 66                }
 67 68                ctx.Close();
 69            }
 70 71var visual = new DrawingVisual();
 72using (var context = visual.RenderOpen())
 73            {
 74                context.DrawGeometry(FillBrush, StrokePen, geometryTest);
 75            }
 76            _visualShape.Add(visual);
 77        }
 78 79#region 内部方法
 80 81        [Obsolete]
 82protectedoverridevoid OnRender(DrawingContext drawingContext)
 83        {
 84//弃用，改为_visualShape填充实现
 85//drawingContext.DrawGeometry(FillBrush, StrokePen, BaseGeometry); 86        }
 87 88protectedoverrideint VisualChildrenCount => _visualShape.Count;
 89 90protectedoverride Visual GetVisualChild(int index)
 91        {
 92if (index < 0 || index >= _visualShape.Count)
 93            {
 94thrownew ArgumentOutOfRangeException();
 95            }
 96 97return _visualShape[index];
 98        }
 99100#endregion101102#region 曲线属性
103104privatereadonly VisualCollection _visualShape;
105protected Brush FillBrush { get; set; } = Brushes.Transparent;
106public Brush LineBrush { get; set; } = Brushes.DarkSeaGreen;
107protecteddouble BorderThickness { get; set; } = 1.0;
108private Pen _defaultPen = null;
109protected Pen StrokePen
110        {
111get112            {
113if (_defaultPen == null)
114                {
115                     _defaultPen = new Pen(LineBrush, BorderThickness);
116                }
117return _defaultPen;
118            }
119set => _defaultPen = value;
120        }
121122#endregion123     }