| public abstract GetEdgeEndpoint ( Point otherEndpoint, Point &edgeEndpoint ) : void | ||
| otherEndpoint | Point | |
| edgeEndpoint | Point | |
| return | void | |
TryGetVertexInformation
(
IVertex oVertex1,
IVertex oVertex2,
out VertexDrawingHistory oVertex1DrawingHistory,
out VertexDrawingHistory oVertex2DrawingHistory,
out Point oEdgeEndpoint1,
out Point oEdgeEndpoint2
)
{
Debug.Assert(oVertex1 != null);
Debug.Assert(oVertex2 != null);
AssertValid();
oVertex1DrawingHistory = oVertex2DrawingHistory = null;
oEdgeEndpoint1 = oEdgeEndpoint2 = new Point();
// Retrieve the information about how the vertices were drawn.
if (
!TryGetVertexDrawingHistory(oVertex1, out oVertex1DrawingHistory)
||
!TryGetVertexDrawingHistory(oVertex2, out oVertex2DrawingHistory)
)
{
// One of the edge's vertices is hidden.
return (false);
}
// The drawing histories determine the edge endpoints. For example, if
// oVertex1 was drawn as a circle, then oVertex1DrawingHistory is a
// CircleVertexDrawingHistory that knows to put its endpoint on the
// circle itself and not at the circle's center.
oVertex1DrawingHistory.GetEdgeEndpoint(
oVertex2DrawingHistory.VertexLocation, out oEdgeEndpoint1);
oVertex2DrawingHistory.GetEdgeEndpoint(
oVertex1DrawingHistory.VertexLocation, out oEdgeEndpoint2);
return (true);
}
DrawCurveThroughIntermediatePoints
(
IEdge oEdge,
GraphDrawingContext oGraphDrawingContext,
DrawingContext oDrawingContext,
VertexDrawingHistory oVertex1DrawingHistory,
VertexDrawingHistory oVertex2DrawingHistory,
Point oEdgeEndpoint1,
Point oEdgeEndpoint2,
Pen oPen
)
{
Debug.Assert(oEdge != null);
Debug.Assert(oGraphDrawingContext != null);
Debug.Assert(oDrawingContext != null);
Debug.Assert(oVertex1DrawingHistory != null);
Debug.Assert(oVertex2DrawingHistory != null);
Debug.Assert(oPen != null);
AssertValid();
// Note: Don't attempt to draw an arrow in this case.
// Create a list of intermediate points, excluding those that fall
// within the vertex bounds. An edge always terminates on the vertex
// bounds, so we don't want it venturing into the vertex itself.
List<Point> oCurvePoints = FilterIntermediatePoints(oEdge,
oVertex1DrawingHistory, oVertex2DrawingHistory);
Int32 iCurvePoints = oCurvePoints.Count;
if (iCurvePoints == 0)
{
// Just draw a straight line.
oDrawingContext.DrawLine(oPen, oEdgeEndpoint1, oEdgeEndpoint2);
return;
}
#if false
// Draw intermediate points for testing.
foreach (Point oPoint in oCurvePoints)
{
oDrawingContext.DrawEllipse(Brushes.Green, null, oPoint, 2, 2);
}
#endif
// The endpoints were originally calculated as if the edge was a
// straight line between the two vertices. Recalculate them so they
// connect more smoothly to the adjacent intermediate curve points.
oVertex1DrawingHistory.GetEdgeEndpoint(oCurvePoints[0],
out oEdgeEndpoint1);
oVertex2DrawingHistory.GetEdgeEndpoint(oCurvePoints[iCurvePoints - 1],
out oEdgeEndpoint2);
oCurvePoints.Insert(0, oEdgeEndpoint1);
oCurvePoints.Add(oEdgeEndpoint2);
PathGeometry oCurveThroughPoints =
WpfPathGeometryUtil.GetCurveThroughPoints(oCurvePoints, 0.5,
CurveThroughIntermediatePointsTolerance);
oDrawingContext.DrawGeometry(null, oPen, oCurveThroughPoints);
// Note: Don't attempt to draw a label in this case.
}