/// <summary>
/// A hopefully faster iterator over the vertices who does not need to create an object each time.
/// </summary>
protected bool FindPrevVertex(ref int controlPointIndex, out RectVertexControlPoint vertex)
{
bool result = false;
LineControlPoint lcp = null;
while (controlPointIndex > 0) {
--controlPointIndex;
lcp = GetControlPoint(controlPointIndex);
if (lcp is RectVertexControlPoint) {
result = true;
break;
}
}
vertex = (RectVertexControlPoint)lcp;
return result;
}
/// <summary>
/// We assume that a valid bending has been assigned to all vertices from the start point up to and
/// including v2
/// </summary>
/// <param name="v1"></param>
/// <param name="v2"></param>
/// <param name="v3"></param>
protected void AssignBending(RectVertexControlPoint v1, RectVertexControlPoint v2, RectVertexControlPoint v3)
{
// Rotate the points such that the connection from v2 to v3 is in the first quadrant
int r = RotateVertices(v1, v2, v3);
//
switch (Geometry.CalcRelativeQuadrant(v1.GetPosition(), v2.GetPosition())) {
case 1: // this is forbidden
// Debug.Assert(false);
// If it happens nevertheless...
switch (v3.bending) {
case VertexBending.None:
if (v2.IsVertical) v3.bending = VertexBending.Right;
else v3.bending = VertexBending.Down;
break;
default:
// We leave it as it is.
break;
}
break;
case 2: //
Debug.Assert(v2.bending == VertexBending.DownU);
// If v3 is the end point, it could already have a bending
switch (v3.bending) {
case VertexBending.None:
v3.bending = VertexBending.Down;
break;
case VertexBending.Down:
case VertexBending.LeftU:
// That is alright.
break;
case VertexBending.UpU:
case VertexBending.Right:
// This causes a double knee, but ok.
break;
case VertexBending.Left:
case VertexBending.Up:
// Conflict, we just override the bending
v3.bending = VertexBending.Down;
break;
default:
Debug.Assert(false);
break;
}
break;
case 3:
// bending of v2 cannot be U
switch (v3.bending) {
case VertexBending.None:
if (v2.IsVertical) v3.bending = VertexBending.Right;
else v3.bending = VertexBending.Down;
break;
case VertexBending.Right:
case VertexBending.Down:
// That is alright.
break;
case VertexBending.LeftU:
v2.bending = VertexBending.Right;
break;
case VertexBending.UpU:
v2.bending = VertexBending.Down;
break;
case VertexBending.Up:
case VertexBending.Left:
// Conflict, we just override the bending
if (v2.IsVertical) v3.bending = VertexBending.Right;
else v3.bending = VertexBending.Down;
break;
default:
Debug.Assert(false);
break;
}
break;
case 4:
Debug.Assert(v2.bending == VertexBending.RightU);
switch (v3.bending) {
case VertexBending.None:
v3.bending = VertexBending.Right;
break;
case VertexBending.Right:
case VertexBending.Down:
case VertexBending.LeftU:
case VertexBending.UpU:
// That is ok
break;
case VertexBending.Left:
case VertexBending.Up:
// Conflict, we just override the bending
v3.bending = VertexBending.Right;
break;
default:
Debug.Assert(false);
break;
}
break;
default:
Debug.Assert(false);
break;
}
UnrotateVertices(r, v1, v2, v3);
}
/// <summary>
/// Assignes the bending.
/// </summary>
protected void AssignBending(RectVertexControlPoint currentVertex, RectVertexControlPoint nextVertex)
{
int r = RotateVertices(null, currentVertex, nextVertex);
switch (nextVertex.bending) {
case VertexBending.None:
if (currentVertex.IsVertical) nextVertex.bending = VertexBending.Right;
else nextVertex.bending = VertexBending.Down;
break;
default:
// We currently assume that this function is only called for unassigned bendings in nextVertex.
Debug.Assert(false);
break;
}
UnrotateVertices(r, null, currentVertex, nextVertex);
}
/// <summary>
/// Rotates the vertices counterclockwise for the number of count quarter rotations.
/// </summary>
protected void UnrotateVertices(int count, RectVertexControlPoint v1, RectVertexControlPoint v2, RectVertexControlPoint v3)
{
// We rotate 4-count times clockwise
for (int i = 0; i < (4 - count) % 4; ++i) {
if (v1 != null) RotateVertex(v1, v2, 1);
RotateVertex(v3, v2, 1);
v2.bending = RotateBending(v2.bending, 1);
}
}
/// <summary>
/// Rotates the vertics around v2 until v3 is in the first quadrant.
/// </summary>
/// <returns>Returns the number of clockwise rotations by 90 degree necessary.</returns>
/// <remarks>Note that our coordinate system is mirrored:
/// III | IV
/// ----|----
/// II | I
/// </remarks>
protected int RotateVertices(RectVertexControlPoint v1, RectVertexControlPoint v2, RectVertexControlPoint v3)
{
int result = 0;
while (Geometry.CalcRelativeQuadrant(v3.GetPosition(), v2.GetPosition()) != 1) {
RotateVertex(v3, v2, 1);
if (v1 != null) RotateVertex(v1, v2, 1);
v2.bending = RotateBending(v2.bending, 1);
++result;
}
return result;
}
/// <summary>
/// Rotates the v1 around origin by 90 degree clockwise.
/// </summary>
protected void RotateVertex(RectVertexControlPoint v, RectVertexControlPoint origin, int count)
{
Point p = v.GetPosition();
Point o = origin.GetPosition();
for (int i = 0; i < count; ++i) {
int x = p.X;
p.X = o.X - (p.Y - o.Y);
p.Y = o.Y + (x - o.X);
v.bending = RotateBending(v.bending, 1);
}
v.SetPosition(p);
}
