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fix: simplify Shape.OffsetOutward winding normalization and sync designer

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OffsetOutward now normalizes to CW winding before offsetting instead of
trial-and-error with bounding box comparison. CadConverterForm designer
regenerated with new entityView1 properties.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
This commit is contained in:
AJ Isaacs
2026-03-29 21:01:46 -04:00
parent 3a0267c041
commit fdb4a2373a
2 changed files with 82 additions and 64 deletions
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49
OpenNest.Core/Geometry/Shape.cs
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@@ -579,43 +579,38 @@ namespace OpenNest.Geometry
}
/// <summary>
/// Offsets the shape outward by the given distance, detecting winding direction
/// to choose the correct offset side. Falls back to the opposite side if the
/// bounding box shrinks (indicating the offset went inward).
/// Offsets the shape outward by the given distance.
/// Normalizes to CW winding before offsetting Left (which is outward for CW),
/// making the method independent of the original contour winding direction.
/// </summary>
public Shape OffsetOutward(double distance)
{
var poly = ToPolygon();
var side = poly.Vertices.Count >= 3 && poly.RotationDirection() == RotationType.CW
? OffsetSide.Left
: OffsetSide.Right;
var result = OffsetEntity(distance, side) as Shape;
if (poly == null || poly.Vertices.Count < 3
|| poly.RotationDirection() == RotationType.CW)
return OffsetEntity(distance, OffsetSide.Left) as Shape;
if (result == null)
return null;
// Shape is CCW — reverse to CW so Left offset goes outward.
var copy = new Shape();
UpdateBounds();
var originalBB = BoundingBox;
result.UpdateBounds();
var offsetBB = result.BoundingBox;
if (offsetBB.Width < originalBB.Width || offsetBB.Length < originalBB.Length)
for (var i = Entities.Count - 1; i >= 0; i--)
{
Trace.TraceWarning(
"Shape.OffsetOutward: offset shrank bounding box " +
$"(original={originalBB.Width:F3}x{originalBB.Length:F3}, " +
$"offset={offsetBB.Width:F3}x{offsetBB.Length:F3}). " +
"Retrying with opposite side.");
var opposite = side == OffsetSide.Left ? OffsetSide.Right : OffsetSide.Left;
var retry = OffsetEntity(distance, opposite) as Shape;
if (retry != null)
result = retry;
switch (Entities[i])
{
case Line l:
copy.Entities.Add(new Line(l.EndPoint, l.StartPoint) { Layer = l.Layer });
break;
case Arc a:
copy.Entities.Add(new Arc(a.Center, a.Radius, a.EndAngle, a.StartAngle, !a.IsReversed) { Layer = a.Layer });
break;
case Circle c:
copy.Entities.Add(new Circle(c.Center, c.Radius) { Layer = c.Layer });
break;
}
}
return result;
return copy.OffsetEntity(distance, OffsetSide.Left) as Shape;
}
/// <summary>