void ProcessExpandingSearchOnSide(int index, List <KeyValuePair <double, Point> > curvePoints, ICurve curve,
double side, double radius,
double distanceFromCurve, Point wh, ref double coveredLength,
PointSetList placedPoints,
double labelLength)
{
foreach (int i in ExpandingSearch(index, 0, curvePoints.Count))
{
KeyValuePair <double, Point> p = curvePoints[i];
Point der = curve.Derivative(p.Key);
if (der.LengthSquared < ApproximateComparer.DistanceEpsilon)
{
continue;
}
Point o = der.Rotate(Math.PI / 2).Normalize() * side;
Point labelPos = p.Value + (radius + distanceFromCurve) * o;
if (!Conflict(labelPos, radius, wh))
{
// found a valid candidate position
var ps = new PointSet
{
Key = p.Key,
Center = labelPos,
Inner = p.Value + distanceFromCurve * o,
Outer = p.Value + (2.0 * radius + distanceFromCurve) * o
};
coveredLength = i <= index
? placedPoints.AddFirst(ps)
: placedPoints.AddLast(ps);
Debug.Assert(Math.Abs(PointSetLength(placedPoints.Points) - coveredLength) < 0.01);
if (coveredLength >= labelLength)
{
break;
}
}
else
{
// not going to work!
break;
}
}
}
void CaseOfCoveredLengthGreaterThanLabelLength(Label label, PointSetList placedPoints, double coveredLength,
double labelLength, Point wh)
{
var innerPoints = new List <Point>();
var outerPoints = new List <Point>();
List <PointSet> orderedPoints = placedPoints.Points.ToList();
double excess = coveredLength - labelLength;
if (excess > 0)
{
// move back the last point
PointSet q = orderedPoints[orderedPoints.Count - 1];
PointSet p = orderedPoints[orderedPoints.Count - 2];
Point v = q.Center - p.Center;
double length = v.Length;
if (excess > length)
{
q = orderedPoints[0];
p = orderedPoints[1];
v = q.Center - p.Center;
length = v.Length;
}
Debug.Assert(length > excess);
Point w = v * ((length - excess) / length);
Debug.Assert(Math.Abs((length - w.Length) - excess) < 0.01);
q.Center = p.Center + w;
q.Inner = p.Inner + w;
q.Outer = p.Outer + w;
}
double cl = PointSetLength(orderedPoints);
Debug.Assert(Math.Abs(cl - labelLength) < 0.01);
GoOverOrderedPointsAndAddLabelObstacels(orderedPoints, innerPoints, outerPoints, wh);
// placed all points in label so we are done
label.InnerPoints = innerPoints;
label.OuterPoints = outerPoints;
}
/// <summary>
/// places a label
/// </summary>
/// <param name="label"></param>
/// <returns></returns>
bool PlaceEdgeLabelOnCurve(Label label)
{
ValidateArg.IsNotNull(label, "label");
// approximate label with a set of circles
// generate list of candidate points for label ordered by priority
// check candidate point for conflicts - if none then stop and keep placement
var edge = (Edge)label.GeometryParent;
label.InnerPoints = null;
List <KeyValuePair <double, Point> > curvePoints = edgePoints[edge];
const double distanceFromCurve = 3;
double radius = label.Height / 2.0;
var wh = new Point(radius, radius);
double labelLength = label.Width;
foreach (int index in ExpandingSearch(StartIndex(label, curvePoints), 0, curvePoints.Count))
{
double[] sides;
var curve = GetSidesAndEdgeCurve(label, edge, curvePoints, index, out sides);
foreach (double side in sides)
{
var placedPoints = new PointSetList();
double coveredLength = 0;
ProcessExpandingSearchOnSide(index, curvePoints, curve, side, radius, distanceFromCurve, wh,
ref coveredLength, placedPoints, labelLength);
if (coveredLength >= labelLength)
{
CaseOfCoveredLengthGreaterThanLabelLength(label, placedPoints, coveredLength, labelLength, wh);
return(true);
}
}
}
return(false);
}
