GetBounds()
{
AssertValid();
if (m_oEdge.IsSelfLoop)
{
Debug.Assert(false);
throw new InvalidOperationException("Edge is self-loop.");
}
// Start with a rectangle that has the same dimensions as the edge, but
// that starts at the origin and has an angle of zero.
Point oVertex1Location = WpfGraphicsUtil.PointFToWpfPoint(
m_oEdge.Vertex1.Location);
Point oVertex2Location = WpfGraphicsUtil.PointFToWpfPoint(
m_oEdge.Vertex2.Location);
Double dLength = WpfGraphicsUtil.GetDistanceBetweenPoints(
oVertex1Location, oVertex2Location);
Double dAngleDegrees = MathUtil.RadiansToDegrees(
WpfGraphicsUtil.GetAngleBetweenPointsRadians(
oVertex1Location, oVertex2Location));
Double dHalfWidth = m_dWidth / 2.0;
Point[] ao4BoundingPoints = new Point[4] {
new Point(0, -dHalfWidth),
new Point(dLength, -dHalfWidth),
new Point(dLength, dHalfWidth),
new Point(0, dHalfWidth),
};
// Rotate the rectangle so it is at the same angle as the edge.
TransformPoints(new RotateTransform(dAngleDegrees), ao4BoundingPoints);
// Translate the rotated rectangle to the location of the edge's first
// endpoint.
TransformPoints(
new TranslateTransform(oVertex1Location.X, oVertex1Location.Y),
ao4BoundingPoints);
// Create a PathGeometry from the bounding points.
return(WpfPathGeometryUtil.GetPathGeometryFromPoints(
ao4BoundingPoints[0],
ao4BoundingPoints[1],
ao4BoundingPoints[2],
ao4BoundingPoints[3]
));
}
GetEdgeEndpointOnCircle
(
Point oVertexALocation,
Double dVertexARadius,
Point oVertexBLocation,
out Point oEdgeEndpoint
)
{
Debug.Assert(dVertexARadius >= 0);
AssertValid();
Double dEdgeAngle = WpfGraphicsUtil.GetAngleBetweenPointsRadians(
oVertexALocation, oVertexBLocation);
oEdgeEndpoint = new Point(
oVertexALocation.X + (dVertexARadius * Math.Cos(dEdgeAngle)),
oVertexALocation.Y - (dVertexARadius * Math.Sin(dEdgeAngle))
);
}
GetEdgeEndpointOnRectangle
(
Point oVertexALocation,
Rect oVertexARectangle,
Point oVertexBLocation,
out Point oEdgeEndpoint
)
{
AssertValid();
if (oVertexALocation == oVertexBLocation)
{
oEdgeEndpoint = oVertexALocation;
return;
}
Double dVertexAX = oVertexALocation.X;
Double dVertexAY = oVertexALocation.Y;
Double dVertexBX = oVertexBLocation.X;
Double dVertexBY = oVertexBLocation.Y;
Double dHalfVertexARectangleWidth = oVertexARectangle.Width / 2.0;
Double dHalfVertexARectangleHeight = oVertexARectangle.Height / 2.0;
// Get the angle between vertex A and vertex B.
Double dEdgeAngle = WpfGraphicsUtil.GetAngleBetweenPointsRadians(
oVertexALocation, oVertexBLocation);
// Get the angle that defines the aspect ratio of vertex A's rectangle.
Double dAspectAngle = Math.Atan2(
dHalfVertexARectangleHeight, dHalfVertexARectangleWidth);
if (dEdgeAngle >= -dAspectAngle && dEdgeAngle < dAspectAngle)
{
// For a square, this is -45 degrees to 45 degrees.
Debug.Assert(dVertexBX != dVertexAX);
oEdgeEndpoint = new Point(
dVertexAX + dHalfVertexARectangleWidth,
dVertexAY + dHalfVertexARectangleWidth *
((dVertexBY - dVertexAY) / (dVertexBX - dVertexAX))
);
return;
}
if (dEdgeAngle >= dAspectAngle && dEdgeAngle < Math.PI - dAspectAngle)
{
// For a square, this is 45 degrees to 135 degrees.
Debug.Assert(dVertexBY != dVertexAY);
oEdgeEndpoint = new Point(
dVertexAX + dHalfVertexARectangleHeight *
((dVertexBX - dVertexAX) / (dVertexAY - dVertexBY)),
dVertexAY - dHalfVertexARectangleHeight
);
return;
}
if (dEdgeAngle < -dAspectAngle && dEdgeAngle >= -Math.PI + dAspectAngle)
{
// For a square, this is -45 degrees to -135 degrees.
Debug.Assert(dVertexBY != dVertexAY);
oEdgeEndpoint = new Point(
dVertexAX + dHalfVertexARectangleHeight *
((dVertexBX - dVertexAX) / (dVertexBY - dVertexAY)),
dVertexAY + dHalfVertexARectangleHeight
);
return;
}
// For a square, this is 135 degrees to 180 degrees and -135 degrees to
// -180 degrees.
Debug.Assert(dVertexAX != dVertexBX);
oEdgeEndpoint = new Point(
dVertexAX - dHalfVertexARectangleWidth,
dVertexAY + dHalfVertexARectangleWidth *
((dVertexBY - dVertexAY) / (dVertexAX - dVertexBX))
);
}
GetEdgeEndpoint
(
Point otherEndpoint,
out Point edgeEndpoint
)
{
AssertValid();
Point oVertexLocation = this.VertexLocation;
// Instead of doing geometry calculations similar to what is done in
// VertexDrawingHistory.GetEdgePointOnRectangle(), make use of that
// method by making the triangle look like a rectangle. First, figure
// out how to rotate the triangle about the vertex location so that the
// side containing the endpoint is vertical and to the right of the
// vertex location.
Double dEdgeAngle = WpfGraphicsUtil.GetAngleBetweenPointsRadians(
oVertexLocation, otherEndpoint);
Double dEdgeAngleDegrees = MathUtil.RadiansToDegrees(dEdgeAngle);
Double dAngleToRotateDegrees;
if (dEdgeAngleDegrees >= -30.0 && dEdgeAngleDegrees < 90.0)
{
dAngleToRotateDegrees = 30.0;
}
else if (dEdgeAngleDegrees >= -150.0 && dEdgeAngleDegrees < -30.0)
{
dAngleToRotateDegrees = 270.0;
}
else
{
dAngleToRotateDegrees = 150.0;
}
// Now create a rotated rectangle that is centered on the vertex
// location and that has the vertical, endpoint-containing triangle
// side as the rectangle's right edge.
Double dWidth = 2.0 * m_dHalfWidth;
Rect oRotatedRectangle = new Rect(
oVertexLocation.X,
oVertexLocation.Y - m_dHalfWidth,
dWidth * WpfGraphicsUtil.Tangent30Degrees,
dWidth
);
Matrix oMatrix = WpfGraphicsUtil.GetRotatedMatrix(oVertexLocation,
dAngleToRotateDegrees);
// Rotate the other vertex location.
Point oRotatedOtherVertexLocation = oMatrix.Transform(otherEndpoint);
// GetEdgeEndpointOnRectangle will compute an endpoint on the
// rectangle's right edge.
Point oRotatedEdgeEndpoint;
GetEdgeEndpointOnRectangle(oVertexLocation, oRotatedRectangle,
oRotatedOtherVertexLocation, out oRotatedEdgeEndpoint);
// Now rotate the edge endpoint in the other direction.
oMatrix = WpfGraphicsUtil.GetRotatedMatrix(oVertexLocation,
-dAngleToRotateDegrees);
edgeEndpoint = oMatrix.Transform(oRotatedEdgeEndpoint);
}
