Finding closest parallel lines in a drawing
Hi,
You can try something like this:
/// <summary>
/// Gets the closest parallel line to baseLine.
/// </summary>
/// <param name="baseLine">The line from wich search the closest parallel.</param>
/// <param name="lines">The line collection where to find the closest parallel.</param>
/// <param name="distance">The distance of the closest patrallel.</param>
/// <returns>The closest parallel line or null if none.</returns>
private Line GetClosestParallel (Line baseLine, IEnumerable<Line> lines, out double distance)
{
var basePoint = baseLine.StartPoint;
var vector = baseLine.EndPoint - basePoint;
Line result = null;
distance = double.MaxValue;
foreach (var line in lines)
{
if (line != baseLine && vector.IsParallelTo(line.EndPoint - line.StartPoint))
{
double dist = line.GetClosestPointTo(basePoint, true).DistanceTo(basePoint);
if (dist < distance)
{
distance = dist;
result = line;
}
}
}
return result;
}
Testing command
[CommandMethod("GCP")]
public void GetClosestParallelCommand()
{
var doc = Application.DocumentManager.MdiActiveDocument;
var db = doc.Database;
var ed = doc.Editor;
var peo = new PromptEntityOptions("\nSelect a line: ");
peo.SetRejectMessage("\nSelected object is not a line.");
peo.AddAllowedClass(typeof(Line), true);
var per = ed.GetEntity(peo);
if (per.Status != PromptStatus.OK)
return;
var psr = ed.GetSelection(new SelectionFilter(new[] { new TypedValue(0, "LINE") }));
if (psr.Status != PromptStatus.OK)
return;
using (var tr = db.TransactionManager.StartTransaction())
{
var line = (Line)tr.GetObject(per.ObjectId, OpenMode.ForRead);
var lines = psr.Value
.Cast<SelectedObject>()
.Select(so => (Line)tr.GetObject(so.ObjectId, OpenMode.ForRead));
var closestParallel = GetClosestParallel(line, lines, out double distance);
if (closestParallel == null)
{
ed.WriteMessage($"\nNo parallel line found.");
}
else
{
ed.WriteMessage($"\nClosest parallel line found at: {distance} units.");
ed.SetImpliedSelection(new[] { closestParallel.ObjectId });
}
tr.Commit();
}
}
