aistudio-wpf-diagram/AIStudio.Wpf.DiagramDesigner/PathGenerators/PathGenerators.Smooth.cs

using System;
using System.Linq;
using AIStudio.Wpf.DiagramDesigner.Geometrys;

namespace AIStudio.Wpf.DiagramDesigner
{
    public static partial class PathGenerators
    {
      

        public static PathGeneratorResult Smooth(IDiagramViewModel _, ConnectionViewModel link, PointBase[] route, PointBase source, PointBase target)
        {
            route = ConcatRouteAndSourceAndTarget(route, source, target);

            if (route.Length > 2)
                return CurveThroughPoints(route, link);

            route = GetRouteWithCurvePoints(link, route);

            double sourceAngle = SourceMarkerAdjustement(route, link.GetSourceMarkerWidth(), link.GetSourceMarkerHeight());
            double targetAngle = TargetMarkerAdjustement(route, link.GetSinkMarkerWidth(), link.GetSinkMarkerHeight());

            DoShift(route, link);

            var path = FormattableString.Invariant($"M {route[0].X} {route[0].Y} C {route[1].X} {route[1].Y}, {route[2].X} {route[2].Y}, {route[3].X} {route[3].Y}");
            return new PathGeneratorResult(new[] { path }, sourceAngle, route[0], targetAngle, route[route.Length - 1]);
        }

        private static PathGeneratorResult CurveThroughPoints(PointBase[] route, ConnectionViewModel link)
        {
            double sourceAngle = SourceMarkerAdjustement(route, link.GetSourceMarkerWidth(), link.GetSourceMarkerHeight());
            double targetAngle = TargetMarkerAdjustement(route, link.GetSinkMarkerWidth(), link.GetSinkMarkerHeight());

            BezierSpline.GetCurveControlPoints(route, out var firstControlPoints, out var secondControlPoints);

            DoShift(route, link);
            DoShift(firstControlPoints, link);
            DoShift(secondControlPoints, link);

            var paths = new string[firstControlPoints.Length];       

            for (var i = 0; i < firstControlPoints.Length; i++)
            {
                var cp1 = firstControlPoints[i];
                var cp2 = secondControlPoints[i];
                paths[i] = FormattableString.Invariant($"M {route[i].X} {route[i].Y} C {cp1.X} {cp1.Y}, {cp2.X} {cp2.Y}, {route[i + 1].X} {route[i + 1].Y}");
            }

            // Todo: adjust marker positions based on closest control points
            return new PathGeneratorResult(paths, sourceAngle, route[0], targetAngle, route[route.Length - 1]);
        }

        private static PointBase[] GetRouteWithCurvePoints(ConnectionViewModel link, PointBase[] route)
        {
            if (link.IsPortless)
            {
                if (Math.Abs(route[0].X - route[1].X) >= Math.Abs(route[0].Y - route[1].Y))
                {
                    var cX = (route[0].X + route[1].X) / 2;
                    return new[] { route[0], new PointBase(cX, route[0].Y), new PointBase(cX, route[1].Y), route[1] };
                }
                else
                {
                    var cY = (route[0].Y + route[1].Y) / 2;
                    return new[] { route[0], new PointBase(route[0].X, cY), new PointBase(route[1].X, cY), route[1] };
                }
            }
            else
            {
                var cX = (route[0].X + route[1].X) / 2;
                var cY = (route[0].Y + route[1].Y) / 2;

                var sourceOrientation = link.SourceConnectorInfo?.Orientation;
                if (sourceOrientation == ConnectorOrientation.None)//按照线条的四象限来处理。
                {
                    var slope = (route[1].Y - route[0].Y) / (route[1].X - route[0].X);
                    if (Math.Abs(slope) < link.SmoothAutoSlope)
                    {
                        if (route[1].X > route[0].X)
                        {
                            sourceOrientation = ConnectorOrientation.Right;
                        }
                        else
                        {
                            sourceOrientation = ConnectorOrientation.Left;
                        }
                    }
                    else
                    {
                        if (route[1].Y > route[0].Y)//Y轴方向是反的
                        {
                            sourceOrientation = ConnectorOrientation.Bottom;
                        }
                        else
                        {
                            sourceOrientation = ConnectorOrientation.Top;
                        }
                    }
               
                }
                var curvePointA = GetCurvePoint(route[0].X, route[0].Y, cX, cY, link.SmoothMargin, sourceOrientation);
                var curvePointB = GetCurvePoint(route[1].X, route[1].Y, cX, cY, link.SmoothMargin, link.SinkConnectorInfo?.Orientation);
                return new[] { route[0], curvePointA, curvePointB, route[1] };
            }
        }

        private static PointBase GetCurvePoint(double pX, double pY, double cX, double cY, double smoothMargin, ConnectorOrientation? alignment)
        {
            var margin = Math.Min(smoothMargin, Math.Pow(Math.Pow(pX - cX, 2) + Math.Pow(pY - cY, 2), .5));
            switch (alignment)
            {
                case ConnectorOrientation.Top: return new PointBase(pX, Math.Min(pY - margin, cY));
                case ConnectorOrientation.Bottom: return new PointBase(pX, Math.Max(pY + margin, cY));
                case ConnectorOrientation.TopRight: return new PointBase(Math.Max(pX + margin, cX), Math.Min(pY - margin, cY));
                case ConnectorOrientation.BottomRight: return new PointBase(Math.Max(pX + margin, cX), Math.Max(pY + margin, cY));
                case ConnectorOrientation.Right: return new PointBase(Math.Max(pX + margin, cX), pY);
                case ConnectorOrientation.Left: return new PointBase(Math.Min(pX - margin, cX), pY);
                case ConnectorOrientation.BottomLeft: return new PointBase(Math.Min(pX - margin, cX), Math.Max(pY + margin, cY));
                case ConnectorOrientation.TopLeft: return new PointBase(Math.Min(pX - margin, cX), Math.Min(pY - margin, cY));
                default: return new PointBase(cX, cY); 
            };
        }

        
    }
}