BoxDiagrams.DiagramGestureAnalyzer.InterpretAsPolyline C# (CSharp) Метод

		private LineOrArrow InterpretAsPolyline(DragState state, List<Section> sections)
		{
			var shape = new LineOrArrow { Style = Control.LineStyle };
			shape.FromAnchor = state.StartAnchor;
			LineSegmentT prevLine = new LineSegmentT(), curLine;

			for (int i = 0; i < sections.Count; i++)
			{
				int angleMod8 = sections[i].AngleMod8;
				var startSS = sections[i].StartSS;
				var endSS = sections[i].EndSS;

				Vector<float> vector = Mod8Vectors[angleMod8];
				Vector<float> perpVector = vector.Rot90();

				bool isStartLine = i == 0;
				bool isEndLine = i == sections.Count - 1;
				if (isStartLine)
				{
					if (shape.FromAnchor != null)
						startSS = shape.FromAnchor.Point;
				}
				if (isEndLine)
				{
					if ((shape.ToAnchor = Control.GetBestAnchor(endSS, angleMod8 + 4)) != null)
						endSS = shape.ToAnchor.Point;
					// Also consider forming a closed shape
					else if (shape.Points.Count > 1
						&& shape.Points[0].Sub(endSS).Length() <= DiagramControl.AnchorSnapDistance
						&& Math.Abs(vector.Cross(shape.Points[1].Sub(shape.Points[0]))) > 0.001f)
						endSS = shape.Points[0];
				}

				if (isStartLine)
					curLine = startSS.To(startSS.Add(vector));
				else
				{
					curLine = endSS.Sub(vector).To(endSS);
					PointT? itsc = prevLine.ComputeIntersection(curLine, LineType.Infinite);
					if (itsc.HasValue)
						startSS = itsc.Value;
				}

				shape.Points.Add(startSS);

				if (isEndLine)
				{
					if (isStartLine)
					{
						Debug.Assert(shape.Points.Count == 1);
						var adjustedStart = startSS.ProjectOntoInfiniteLine(endSS.Sub(vector).To(endSS));
						var adjustedEnd = endSS.ProjectOntoInfiniteLine(curLine);
						if (shape.FromAnchor != null)
						{
							if (shape.ToAnchor != null)
							{
								// Both ends anchored => do nothing, allow unusual angle
							}
							else
							{
								// Adjust endpoint to maintain angle
								endSS = adjustedEnd;
							}
						}
						else
						{
							if (shape.ToAnchor != null)
								// End anchored only => alter start point
								shape.Points[0] = adjustedStart;
							else
							{
								// Neither end anchored => use average line
								shape.Points[0] = startSS.To(adjustedStart).Midpoint();
								endSS = endSS.To(adjustedEnd).Midpoint();
							}
						}
					}
					shape.Points.Add(endSS);
				}
				prevLine = curLine;
			}

			shape.FromArrow = Control.FromArrow;
			shape.ToArrow = Control.ToArrow;

			return shape;
		}