/// <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>
/// Does any edge of this closed shape intersect a line segment?
/// </summary>
/// <param name="ps">The start of the segment</param>
/// <param name="pe">The end of the segment</param>
/// <returns>True if any edge of this shape intersects the segment</returns>
bool IsOverlap(IPointGeometry ps, IPointGeometry pe)
{
Window segwin = new Window(ps, pe);
if (!m_Extent.IsOverlap(segwin))
{
return(false);
}
// Define the test segment.
ITerminal ts = new FloatingTerminal(ps);
ITerminal te = new FloatingTerminal(pe);
SegmentGeometry seg = new SegmentGeometry(ts, te);
return(IsIntersect(seg));
}
/// <summary>
/// Does any edge of this closed shape intersect a line segment?
/// </summary>
/// <param name="ps">The start of the segment</param>
/// <param name="pe">The end of the segment</param>
/// <returns>True if any edge of this shape intersects the segment</returns>
bool IsOverlap(IPointGeometry ps, IPointGeometry pe)
{
Window segwin = new Window(ps, pe);
if (!m_Extent.IsOverlap(segwin))
return false;
// Define the test segment.
ITerminal ts = new FloatingTerminal(ps);
ITerminal te = new FloatingTerminal(pe);
SegmentGeometry seg = new SegmentGeometry(ts, te);
return IsIntersect(seg);
}
/// <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;
}
}
