/// <summary>
/// Constructor used to combine a series of <c>IntersectResult</c> objects. This
/// implementation is used to obtain a results object for a new topological line
/// that has just been intersected against the map.
/// </summary>
/// <param name="xsect">The result of intersecting a line with the map</param>
internal IntersectionResult(IntersectionFinder xsect)
{
m_IntersectedObject = xsect.Intersector;
m_Geom = m_IntersectedObject.LineGeometry;
m_Data = null;
// Get the total number of intersections that were found (there's one
// InteresectionResult for each intersected line)
IList<IntersectionResult> results = xsect.Intersections;
int nData = 0;
foreach (IntersectionResult r in results)
nData += r.m_Data.Count;
// Return if no intersections.
if (nData==0)
return;
// Copy over the info
m_Data = new List<IntersectionData>(nData);
foreach (IntersectionResult r in results)
{
List<IntersectionData> data = r.Intersections;
foreach (IntersectionData d in data)
m_Data.Add(d);
}
// Reverse all context codes.
foreach (IntersectionData d in m_Data)
d.ReverseContext();
}
/// <summary>
/// Confirms that a potential link is valid. For a link to be valid, the
/// midpoint of the link must fall inside the specified polygon, and the
/// line connecting the 2 points cannot intersect anything.
/// </summary>
/// <param name="other">The end of the proposed point to link to.</param>
/// <param name="pol">The polygon the link must fall completely inside.</param>
/// <returns>True if link is valid.</returns>
internal bool IsLinkValid(PolygonLink other, Polygon pol)
{
// 22-MAR-00 There may be no point at a corner.
if (m_Point == null || other.Point == null)
{
return(false);
}
// Get the midpoint of the link.
IPosition mid = Geom.MidPoint(m_Point, other.Point);
// Confirm the midpoint falls inside the right polygon.
if (!pol.IsRingEnclosing(mid))
{
return(false);
}
// Locate any intersections formed by the proposed link (considering
// only the currently active theme).
LineGeometry seg = new SegmentGeometry(m_Point, other.m_Point);
IntersectionFinder xsect = new IntersectionFinder(seg, true);
// The proposed link is not valid if it intersects anything
// along the length of the segment, or has any grazes.
if (xsect.IsGrazing || xsect.IsSplitNeeded)
{
return(false);
}
return(true);
}
/// <summary>
/// Updates info on the longest horizontal span that crosses this polygon (used
/// by <see cref="GetLabelPosition"/>)
/// </summary>
/// <param name="y">The Y-value of the scan line.</param>
/// <param name="minx">The X-value for the western end of the scan line.</param>
/// <param name="maxx">The X-value for the eastern end of the scan line.</param>
/// <param name="weight">Weighting factor to use when comparing span lengths versus
/// the initial best length.</param>
/// <param name="beststart">The position of the start of the best span.</param>
/// <param name="bestend">The position of the end of the best span.</param>
/// <param name="bestlen">The weighted length of the best span. This is what defines
/// the meaning of "best".</param>
void GetLabelSpan(double y, double minx, double maxx, double weight,
ref IPosition beststart, ref IPosition bestend, ref double bestlen)
{
// Define scan line.
ITerminal sloc = new FloatingTerminal(minx, y);
ITerminal eloc = new FloatingTerminal(maxx, y);
SegmentGeometry seg = new SegmentGeometry(sloc, eloc);
// Intersect with the map
IntersectionFinder xseg = new IntersectionFinder(seg, true);
// Arrange intersections along the scan line.
IntersectionResult xres = new IntersectionResult(xseg);
xres.Sort(true);
// Define start of the first span
IPosition start = sloc;
IPosition end = null;
// Go through each successive intersection, to locate spans
// that run through the interior of the polygon.
foreach (IntersectionData d in xres.Intersections)
{
// If the intersection is a graze
if (d.IsGraze)
{
// Just define the end of the graze as the end point (there's
// no point in trying to locate a label along the graze).
end = d.P2;
}
else
{
// Simple intersection...
// Get the next intersection
end = d.P1;
// Get the midpoint of the span.
IPosition mid = Position.CreateMidpoint(start, end);
// If the midpoint really falls inside this polygon, see whether the span
// length is bigger than what we already have (if anything).
if (this.IsEnclosing(mid))
{
double len = (end.X - start.X) / weight;
if (len > bestlen)
{
bestlen = len;
beststart = start;
bestend = end;
}
}
}
start = end;
}
}
/// <summary>
/// Constructor used to combine a series of <c>IntersectResult</c> objects. This
/// implementation is used to obtain a results object for a new topological line
/// that has just been intersected against the map.
/// </summary>
/// <param name="xsect">The result of intersecting a line with the map</param>
internal IntersectionResult(IntersectionFinder xsect)
{
m_IntersectedObject = xsect.Intersector;
m_Geom = m_IntersectedObject.LineGeometry;
m_Data = null;
// Get the total number of intersections that were found (there's one
// InteresectionResult for each intersected line)
IList <IntersectionResult> results = xsect.Intersections;
int nData = 0;
foreach (IntersectionResult r in results)
{
nData += r.m_Data.Count;
}
// Return if no intersections.
if (nData == 0)
{
return;
}
// Copy over the info
m_Data = new List <IntersectionData>(nData);
foreach (IntersectionResult r in results)
{
List <IntersectionData> data = r.Intersections;
foreach (IntersectionData d in data)
{
m_Data.Add(d);
}
}
// Reverse all context codes.
foreach (IntersectionData d in m_Data)
{
d.ReverseContext();
}
}
/// <summary>
/// Do any splits needed upon addition of a new line.
/// </summary>
/// <param name="arePolygonsBuilt">Has polygon topology been built (false if the split
/// is being done as part of the initial load).</param>
/// <param name="retrims">Intersecting lines that were split on the invisible
/// portion of a trimmed line. The lines in this list will need to be re-trimmed.
/// </param>
/// <remarks>
/// 15-NOV-99: This function used to be called all over the place. It should now
/// be called ONLY by <see cref="CadastralMapModel.Intersect"/>. To indicate that
/// a line needs to be intersected, set the <see cref="IsMoved"/> property to
/// true.
/// </remarks>
internal void Split(bool arePolygonsBuilt, List<LineFeature> retrims)
{
// No need to split lines that aren't topological.
if (!IsTopological)
return;
if (m_Topology==null)
throw new Exception("LineFeature.Split - topology hasn't been initialized");
// This method should only be called for complete lines (with no pre-existing
// topological sections)
if (!(m_Topology is LineTopology))
{
string msg = String.Format("LineFeature.Split - Line {0} is associated with the wrong type of topology ({1})",
InternalId, m_Topology.GetType().Name);
throw new Exception(msg);
}
LineTopology lineTop = (LineTopology)m_Topology;
// Intersect this line with the map (ignoring end to end intersects).
IntersectionFinder xf = new IntersectionFinder(this, false);
// Return if no intersections.
IList<IntersectionResult> intersectedDividers = xf.Intersections;
if (intersectedDividers.Count==0)
return;
// Cut up the things that were intersected, making grazing portions non-topological.
// Each result object should be associated with an IDivider.
foreach (IntersectionResult r in intersectedDividers)
Cut(arePolygonsBuilt, r, retrims);
// Combine the results and get the splitter to cut itself up.
IntersectionResult xres = new IntersectionResult(xf);
if (arePolygonsBuilt)
{
// If there is a graze at the start of this line, ensure
// that all polygons incident on the start location have
// been marked for deletion. Same for the end.
if (xres.IsStartGrazing)
Topology.MarkPolygons(StartPoint);
if (xres.IsEndGrazing)
Topology.MarkPolygons(EndPoint);
}
// Modify the intersection results so that the exit point
// of each graze will be treated as a simple intersection.
// While at it, ensure there are no duplicates, and ensure
// we don't have any intersections at the end of the line.
if (xres.Simplify()==0)
return;
// Create divider sections. We should make at least ONE split.
Cut(arePolygonsBuilt, xres, retrims);
}
/// <summary>
/// Updates info on the longest horizontal span that crosses this polygon (used
/// by <see cref="GetLabelPosition"/>)
/// </summary>
/// <param name="y">The Y-value of the scan line.</param>
/// <param name="minx">The X-value for the western end of the scan line.</param>
/// <param name="maxx">The X-value for the eastern end of the scan line.</param>
/// <param name="weight">Weighting factor to use when comparing span lengths versus
/// the initial best length.</param>
/// <param name="beststart">The position of the start of the best span.</param>
/// <param name="bestend">The position of the end of the best span.</param>
/// <param name="bestlen">The weighted length of the best span. This is what defines
/// the meaning of "best".</param>
void GetLabelSpan(double y, double minx, double maxx, double weight,
ref IPosition beststart, ref IPosition bestend, ref double bestlen)
{
// Define scan line.
ITerminal sloc = new FloatingTerminal(minx, y);
ITerminal eloc = new FloatingTerminal(maxx, y);
SegmentGeometry seg = new SegmentGeometry(sloc, eloc);
// Intersect with the map
IntersectionFinder xseg = new IntersectionFinder(seg, true);
// Arrange intersections along the scan line.
IntersectionResult xres = new IntersectionResult(xseg);
xres.Sort(true);
// Define start of the first span
IPosition start = sloc;
IPosition end = null;
// Go through each successive intersection, to locate spans
// that run through the interior of the polygon.
foreach (IntersectionData d in xres.Intersections)
{
// If the intersection is a graze
if (d.IsGraze)
{
// Just define the end of the graze as the end point (there's
// no point in trying to locate a label along the graze).
end = d.P2;
}
else
{
// Simple intersection...
// Get the next intersection
end = d.P1;
// Get the midpoint of the span.
IPosition mid = Position.CreateMidpoint(start, end);
// If the midpoint really falls inside this polygon, see whether the span
// length is bigger than what we already have (if anything).
if (this.IsEnclosing(mid))
{
double len = (end.X - start.X)/weight;
if (len>bestlen)
{
bestlen = len;
beststart = start;
bestend = end;
}
}
}
start = end;
}
}
