// This is where the real work is done.
public void AddLine(double x, double y, double?z, double?m)
{
// To unify code for ascending and descending measures - clipPointMeasure
double?clipPointMeasure = GetClipPointMeasure(m);
double newX, newY;
// If current measure is between start measure and end measure,
// we should add segment to the result linestring
if (m.IsWithinRange(_clipStartMeasure, _clipEndMeasure))
{
// if the geometry is started, just add the point to line
if (_started)
{
_target.AddLine(x, y, z, m);
}
// Else we need to begin the geom figure first
else
{
var isShapePoint = false;
// if clip point is shape point measure then add the point without computation
if (m.EqualsTo(clipPointMeasure))
{
_target.BeginFigure(x, y, null, m);
isShapePoint = true;
}
else
{
ComputePointCoordinates(clipPointMeasure, m, x, y, out newX, out newY);
// if computed point is within tolerance of last point then begin figure with last point
if (Ext.IsWithinTolerance(_previousX, _previousY, newX, newY, _tolerance))
{
_target.BeginFigure(_previousX, _previousY, null, _retainClipMeasure ? _clipStartMeasure : _previousM);
}
// check with current point against new computed point
else if (Ext.IsWithinTolerance(x, y, newX, newY, _tolerance))
{
_target.BeginFigure(x, y, null, m);
isShapePoint = true;
}
// else begin figure with clipped point
else
{
_target.BeginFigure(newX, newY, null, clipPointMeasure);
}
}
_started = true;
if (_clipStartMeasure.EqualsTo(_clipEndMeasure) || isShapePoint)
{
UpdateLastPoint(x, y, m);
return;
}
_target.AddLine(x, y, z, m);
}
}
// We may still need to add last segment,
// if current point is the first one after we passed range of interest
else
{
if (!_started)
{
var isShapePoint = false;
if (clipPointMeasure.IsWithinRange(m, _previousM))
{
ComputePointCoordinates(clipPointMeasure, m, x, y, out newX, out newY);
// if computed point is within tolerance of last point then begin figure with last point
if (Ext.IsWithinTolerance(_previousX, _previousY, newX, newY, _tolerance))
{
_target.BeginFigure(_previousX, _previousY, null, _retainClipMeasure ? clipPointMeasure : _previousM);
}
// check with current point against new computed point
else if (Ext.IsWithinTolerance(x, y, newX, newY, _tolerance))
{
_target.BeginFigure(x, y, null, _retainClipMeasure ? clipPointMeasure : m);
isShapePoint = true;
}
// else begin figure with clipped point
else
{
_target.BeginFigure(newX, newY, null, clipPointMeasure);
}
_started = true;
if (_clipStartMeasure.EqualsTo(_clipEndMeasure) || isShapePoint)
{
UpdateLastPoint(x, y, m);
return;
}
}
}
if (_started && !_finished)
{
// re calculate clip point measure as it can be changed from above condition.
clipPointMeasure = GetClipPointMeasure(m);
if (clipPointMeasure.IsWithinRange(m, _previousM))
{
ComputePointCoordinates(clipPointMeasure, m, x, y, out newX, out newY);
var isWithinLastPoint = Ext.IsWithinTolerance(_previousX, _previousY, newX, newY, _tolerance);
var isWithinCurrentPoint = Ext.IsWithinTolerance(x, y, newX, newY, _tolerance);
// if computed point is within tolerance of last point then skip
if (!isWithinLastPoint)
{
// if within current point then add current point
if (isWithinCurrentPoint)
{
_target.AddLine(x, y, null, _retainClipMeasure ? clipPointMeasure : m);
}
// else add computed point
else
{
_target.AddLine(newX, newY, null, clipPointMeasure);
}
}
_finished = true;
}
}
}
// re-assign the current co-ordinates to match for next iteration.
UpdateLastPoint(x, y, m);
}
