C#开发PACS医学影像处理系统(十三)：绘图处理之病灶测量

接上一篇文章，当我们可以绘制图形标记后，就可以在此操作类上面进行扩展，

比如测量类工具，目前整理出的常用绘图和测量功能如下：

测量工具类：（图形标记类请参考本系列文章：绘图处理之图形标记）

功能	说明
标尺	线段长度测量
折尺	曲线长度测量
心胸比	两根线段按比例测量
交叉尺	两根线段互相垂直测量
Cobb角	两根线段的垂线交点角度测量，一般用于脊柱曲率
开角	两根线段的延长交点的角度测量
T型尺	两根线段相交的任意角度摇摆测量和长度测量
角度测量	角度测量
圆形测量	圆形或椭圆面积测量，包括CT值，平均值，方差，最大最小值
矩形测量	矩形面积测量，包括CT值，平均值，方差，最大最小值
多边形测量	多边形面积

以线段测量为例，看效果：

在绘制图形的基础上，我们创建一个Text Block来显示测量结果：

 　　　　//文本对象
        TextBlock txtMeasure;

        /// <summary>
        /// 创建测量结果文本
        /// </summary>
        /// <param name="point"></param>
        public void CreateMeasure(Point point)
        {
            if (!isMeasure)
            {
                return;
            }

            txtMeasure = new TextBlock();
            txtMeasure.Text = "0.0mm";
            txtMeasure.FontSize = ShapeManager.shapeMeasureFontSize;
            txtMeasure.Foreground = ShapeManager.shapeMeasureColor;
            txtMeasure.Height = 30;
            txtMeasure.Width = 100;
            txtMeasure.SetValue(Canvas.LeftProperty, point.X);
            txtMeasure.SetValue(Canvas.TopProperty, point.Y);
            canvas.Children.Add(txtMeasure);
            measureList.Add(txtMeasure);

        }

计算两点之间的距离：其中dpi是缩放比例

 　　　  /// <summary>
        /// 求平面中两点之间距离
        /// </summary>
        /// <param name="p1">点1</param>
        /// <param name="p2">点2</param>
        /// <returns></returns>
        public static double GetDistance(Point p1, Point p2)
        {
            double result = 0;
            result = Math.Sqrt((p1.X * dpiX - p2.X * dpiX) * (p1.X * dpiX - p2.X * dpiX) + (p1.Y * dpiY - p2.Y * dpiY) * (p1.Y * dpiY - p2.Y * dpiY));
            return result;
        }

一些角度类型的测量计算相对复杂一点，需要计算角度大小和绘制弧线

　　　　 /// <summary>
        /// 弧线画笔对象
        /// </summary>
        public Stroke circleStroke;


        /// <summary>
        /// 绘制角度弧线
        /// </summary>
        private void DrawAxiesCircle(Point point0, Point point1, Point point2)
        {

            if (inkCanvas.Strokes.Count > 0 && circleStroke != null)
            {
                if (inkCanvas.Strokes.Contains(circleStroke))
                {
                    inkCanvas.Strokes.Remove(circleStroke);
                }
            }

            //计算角度
            double a = Math.Sqrt((point1.X - point2.X) * (point1.X - point2.X) + (point1.Y - point2.Y) * (point1.Y - point2.Y));
            double b = Math.Sqrt((point1.X - point0.X) * (point1.X - point0.X) + (point1.Y - point0.Y) * (point1.Y - point0.Y));
            double c = Math.Sqrt((point2.X - point0.X) * (point2.X - point0.X) + (point2.Y - point0.Y) * (point2.Y - point0.Y));
            double cTheta = (a * a + b * b - c * c) / (2 * a * b);
            double theta = Math.Acos(cTheta) * 180 / Math.PI;

            //绘制弧线
            double r = 30;
            r = a > b ? b : a;
            double rMax = a;
            if (rMax > b)
            {
                rMax = b;
            }
            if (r > 0.5 * rMax)
            {
                r = 0.5 * rMax;
            }

            double theta0 = Math.Atan((point1.Y - point2.Y) / (point2.X - point1.X + 1e-10)) * 180 / Math.PI;
            if (point1.X > point2.X)
            {
                theta0 = 180 + theta0;
            }
            List<Point> pointList = new List<Point>();
            double sin_ab = ((point2.X - point1.X) * (point0.Y - point1.Y) - (point2.Y - point1.Y) * (point0.X - point1.X)) / (a * b); ;
            if (sin_ab <= 0)
            {

                if (theta < 1)
                {
                    for (double delta = 0.0001; delta <= theta;)
                    {
                        double th = delta + theta0;
                        pointList.Add(new Point(point1.X + r * Math.Cos(th * Math.PI / 180), point1.Y - r * Math.Sin(th * Math.PI / 180)));
                        delta = delta + 0.0001;
                    }
                }
                else if (theta > 1 && theta < 20)
                {
                    for (double delta = 0.01; delta <= theta;)
                    {
                        double th = delta + theta0;
                        pointList.Add(new Point(point1.X + r * Math.Cos(th * Math.PI / 180), point1.Y - r * Math.Sin(th * Math.PI / 180)));
                        delta = delta + 0.01;
                    }
                }
                else
                {
                    for (double delta = 0; delta <= theta; delta++)
                    {
                        double th = delta + theta0;
                        pointList.Add(new Point(point1.X + r * Math.Cos(th * Math.PI / 180), point1.Y - r * Math.Sin(th * Math.PI / 180)));
                    }
                }
            }
            else
            {
                if (theta < 1)
                {
                    for (double delta = -theta; delta <= 0;)
                    {
                        double th = delta + theta0;
                        pointList.Add(new Point(point1.X + r * Math.Cos(th * Math.PI / 180), point1.Y - r * Math.Sin(th * Math.PI / 180)));
                        delta = delta + 0.0001;
                    }
                }
                else if (theta > 1 && theta < 20)
                {
                    for (double delta = -theta; delta <= 0;)
                    {
                        double th = delta + theta0;
                        pointList.Add(new Point(point1.X + r * Math.Cos(th * Math.PI / 180), point1.Y - r * Math.Sin(th * Math.PI / 180)));
                        delta = delta + 0.01;
                    }
                }
                else
                {
                    for (double delta = -theta; delta <= 0; delta++)
                    {
                        double th = delta + theta0;
                        pointList.Add(new Point(point1.X + r * Math.Cos(th * Math.PI / 180), point1.Y - r * Math.Sin(th * Math.PI / 180)));
                    }
                }
            }
            if (pointList.Count > 0)
            {
                StylusPointCollection point = new StylusPointCollection(pointList);
                circleStroke = new Stroke(point)
                {
                    DrawingAttributes = inkCanvas.DefaultDrawingAttributes.Clone(),
                };
                inkCanvas.Strokes.Add(circleStroke);
                txt.Text = theta.ToString(ShapeManager.measureDigit) + "°";
            }
            ReSetAnglePoint();
        }

在圆形和矩形的面积测量中，我们可以使用GetArea()方法来获取图形面积：

  　　　 /// <summary>
        /// 计算面积测量结果
        /// </summary>
        public void CalculateMeasure()
        {
            if (!isMeasure)
            {
                return;
            }
            Ellipse ellipse = (Ellipse)shape;
            ellipse.UpdateLayout();
            txtMeasure.Text = Math.Sqrt(ellipse.RenderedGeometry.GetArea()).ToString(ShapeManager.measureDigit) + "mm²";
            ReSetMeasurePoint();
        }

其他一些需要注意的细节：

1.当单元格放大缩小时，图形也要重新计算各个控制点的位置来同步放大或缩小

监听画布大小变化事件：

private void ToolInkCanvas_SizeChanged(object sender, SizeChangedEventArgs e)

重新绘制元素：

  　　　 /// <summary>
        /// 重新绘制画布元素大小
        /// </summary>
        public void ReSetShapeSize()
        {
            for (int i = 0; i < shapeManager.shapeList.Count; i++)
            {
                sizeScaleX = ToolInkCanvas.ActualWidth / shapeManager.shapeList[i].cvsWidth;
                sizeScaleY = ToolInkCanvas.ActualHeight / shapeManager.shapeList[i].cvsHeight;

                shapeManager.shapeList[i].cvsWidth = ToolInkCanvas.ActualWidth;
                shapeManager.shapeList[i].cvsHeight = ToolInkCanvas.ActualHeight;

                if (shapeManager.shapeList[i] is TextInfo)
                {
                    shapeManager.shapeList[i].ReSetScalePoints(sizeScaleX, sizeScaleY, "text", shapeManager.shapeList[i]);
                }
                else if (shapeManager.shapeList[i] is CrossRulerInfo)
                {
                    shapeManager.shapeList[i].ReSetScalePoints(sizeScaleX, sizeScaleY, "crossRuler", shapeManager.shapeList[i]);
                }
                else if (shapeManager.shapeList[i] is AngleRulerInfo)
                {
                    shapeManager.shapeList[i].ReSetScalePoints(sizeScaleX, sizeScaleY, "angle", shapeManager.shapeList[i]);
                }
                else if (shapeManager.shapeList[i] is TRulerInfo)
                {
                    shapeManager.shapeList[i].ReSetScalePoints(sizeScaleX, sizeScaleY, "tRulerInfo", shapeManager.shapeList[i]);
                }
                else if (shapeManager.shapeList[i] is CobbAngleInfo)
                {
                    shapeManager.shapeList[i].ReSetScalePoints(sizeScaleX, sizeScaleY, "cobbAngleInfo", shapeManager.shapeList[i]);
                }
                else if (shapeManager.shapeList[i] is OpenAngleInfo)
                {
                    shapeManager.shapeList[i].ReSetScalePoints(sizeScaleX, sizeScaleY, "openAngleInfo", shapeManager.shapeList[i]);
                }
                else
                {
                    shapeManager.shapeList[i].ReSetScalePoints(sizeScaleX, sizeScaleY);
                }
            }
        }