source: branches/HeuristicLab.Problems.GrammaticalOptimization/SharpVectorRenderingGdi/Gdi/GdiMarkerRendering.cs @ 13857

using System;
using System.Xml;
using System.Drawing;
using System.Drawing.Drawing2D;

using SharpVectors.Dom.Svg;

namespace SharpVectors.Renderers.Gdi
{
  public enum SvgMarkerPosition{Start, Mid, End}

    public sealed class GdiMarkerRendering : GdiRendering
  {
        #region Constructors and Destructor

    public GdiMarkerRendering(SvgElement element) : base(element)
    {
    }

        #endregion

        #region Public Methods

        // disable default rendering
        public override void BeforeRender(GdiGraphicsRenderer renderer)
    {
    }
        public override void Render(GdiGraphicsRenderer renderer)
        {
        }
        public override void AfterRender(GdiGraphicsRenderer renderer)
        {
        }

    public void PaintMarker(GdiGraphicsRenderer renderer, GdiGraphicsWrapper gr, 
            SvgMarkerPosition markerPos, SvgStyleableElement refElement)
    {
      ISharpMarkerHost markerHostElm = (ISharpMarkerHost)refElement;
      SvgMarkerElement markerElm     = (SvgMarkerElement) element;

            SvgPointF[] vertexPositions = markerHostElm.MarkerPositions;
      int start;
      int len;

      // Choose which part of the position array to use
      switch (markerPos)
      {
        case SvgMarkerPosition.Start:
          start = 0;
          len = 1;
          break;
        case SvgMarkerPosition.Mid:
          start = 1;
          len = vertexPositions.Length - 2;
          break;
        default:
          // == MarkerPosition.End
          start = vertexPositions.Length-1;
          len = 1;
          break;
      }

      for (int i = start; i < start+len; i++)
      {
                SvgPointF point = vertexPositions[i];

        GdiGraphicsContainer gc = gr.BeginContainer();

        gr.TranslateTransform(point.X, point.Y);

        if (markerElm.OrientType.AnimVal.Equals(SvgMarkerOrient.Angle))
        {
          gr.RotateTransform((float)markerElm.OrientAngle.AnimVal.Value);
        }
        else
        {
                    double angle;

          switch(markerPos)
          {
            case SvgMarkerPosition.Start:
              angle = markerHostElm.GetStartAngle(i + 1);
              break;
            case SvgMarkerPosition.Mid:
              //angle = (markerHostElm.GetEndAngle(i) + markerHostElm.GetStartAngle(i + 1)) / 2;
              angle = SvgNumber.CalcAngleBisection(markerHostElm.GetEndAngle(i), markerHostElm.GetStartAngle(i + 1));
              break;
            default:
              angle = markerHostElm.GetEndAngle(i);
              break;
          }
          gr.RotateTransform((float)angle);
        }

        if (markerElm.MarkerUnits.AnimVal.Equals(SvgMarkerUnit.StrokeWidth))
        {
          SvgLength strokeWidthLength = new SvgLength(refElement, 
                        "stroke-width", SvgLengthSource.Css, SvgLengthDirection.Viewport, "1");
          float strokeWidth = (float)strokeWidthLength.Value;
          gr.ScaleTransform(strokeWidth, strokeWidth);
        }

        SvgPreserveAspectRatio spar = 
                    (SvgPreserveAspectRatio)markerElm.PreserveAspectRatio.AnimVal;
                double[] translateAndScale = spar.FitToViewBox((SvgRect)markerElm.ViewBox.AnimVal,
          new SvgRect(0, 0, markerElm.MarkerWidth.AnimVal.Value,
            markerElm.MarkerHeight.AnimVal.Value));


        gr.TranslateTransform(-(float)(markerElm.RefX.AnimVal.Value * translateAndScale[2]),
          -(float)(markerElm.RefY.AnimVal.Value * translateAndScale[3]));

        gr.ScaleTransform((float)translateAndScale[2], (float)translateAndScale[3]);

        Clip(gr);
                             
                renderer.RenderChildren(markerElm);

        gr.EndContainer(gc);
      }
    }

        #endregion
  }
}