Add Gravograph IS post processor

This commit is contained in:
2026-05-23 12:40:53 -04:00
parent 86582d28c3
commit 987a5e25bc
15 changed files with 1791 additions and 0 deletions
@@ -0,0 +1,196 @@
using System;
using System.Collections.Generic;
using OpenNest.Geometry;
namespace OpenNest.Posts.GravographIS
{
/// <summary>
/// Geometry pre-pass for the Gravograph IS8000 backend. The machine is a dumb
/// executor — it never reorders geometry and always lifts between separate
/// entities — so we stitch shared-endpoint polylines together and reorder by
/// nearest-neighbor before encoding.
/// </summary>
public static class PolylinePrePass
{
public const double DefaultStitchTolerance = 1e-6;
/// <summary>
/// Joins polylines whose endpoints coincide (within <paramref name="tolerance"/>)
/// into single continuous polylines. Polylines with fewer than two points are
/// dropped. Direction is reversed as needed to make a join. Each input polyline
/// is copied — the inputs are not mutated.
/// </summary>
public static List<List<Vector>> Stitch(
IEnumerable<IReadOnlyList<Vector>> polylines,
double tolerance = DefaultStitchTolerance)
{
if (polylines == null) throw new ArgumentNullException(nameof(polylines));
var segs = new List<List<Vector>>();
foreach (var p in polylines)
{
if (p == null || p.Count < 2)
continue;
segs.Add(new List<Vector>(p));
}
bool changed;
do
{
changed = false;
for (int i = 0; i < segs.Count; i++)
{
var a = segs[i];
for (int j = 0; j < segs.Count; j++)
{
if (i == j) continue;
var b = segs[j];
// a-end ↔ b-start: append b to a (skip duplicated joint)
if (Near(a[a.Count - 1], b[0], tolerance))
{
for (int k = 1; k < b.Count; k++) a.Add(b[k]);
segs.RemoveAt(j);
if (j < i) i--;
changed = true;
break;
}
// a-end ↔ b-end: append reversed b to a
if (Near(a[a.Count - 1], b[b.Count - 1], tolerance))
{
for (int k = b.Count - 2; k >= 0; k--) a.Add(b[k]);
segs.RemoveAt(j);
if (j < i) i--;
changed = true;
break;
}
// a-start ↔ b-end: prepend b to a
if (Near(a[0], b[b.Count - 1], tolerance))
{
var combined = new List<Vector>(b.Count + a.Count - 1);
combined.AddRange(b);
for (int k = 1; k < a.Count; k++) combined.Add(a[k]);
segs[i] = combined;
segs.RemoveAt(j);
if (j < i) i--;
changed = true;
break;
}
// a-start ↔ b-start: prepend reversed b to a
if (Near(a[0], b[0], tolerance))
{
var combined = new List<Vector>(b.Count + a.Count - 1);
for (int k = b.Count - 1; k >= 0; k--) combined.Add(b[k]);
for (int k = 1; k < a.Count; k++) combined.Add(a[k]);
segs[i] = combined;
segs.RemoveAt(j);
if (j < i) i--;
changed = true;
break;
}
}
if (changed) break;
}
}
while (changed);
return segs;
}
/// <summary>
/// Greedy nearest-neighbor ordering of polylines starting from
/// <paramref name="origin"/> (defaults to 0,0 = the work origin = the first
/// polyline's first point on the wire). When <paramref name="allowReverse"/>
/// is true a polyline may be reversed if its tail is closer than its head.
/// </summary>
public static List<List<Vector>> Reorder(
IEnumerable<IReadOnlyList<Vector>> polylines,
bool allowReverse = true,
Vector? origin = null)
{
if (polylines == null) throw new ArgumentNullException(nameof(polylines));
var pool = new List<List<Vector>>();
foreach (var p in polylines)
{
if (p == null || p.Count < 2)
continue;
pool.Add(new List<Vector>(p));
}
var ordered = new List<List<Vector>>(pool.Count);
var current = origin ?? new Vector(0, 0);
while (pool.Count > 0)
{
var bestIdx = -1;
var bestReverse = false;
var bestDistSq = double.PositiveInfinity;
for (int i = 0; i < pool.Count; i++)
{
var p = pool[i];
var dHead = SquaredDistance(current, p[0]);
if (dHead < bestDistSq)
{
bestDistSq = dHead;
bestIdx = i;
bestReverse = false;
}
if (allowReverse)
{
var dTail = SquaredDistance(current, p[p.Count - 1]);
if (dTail < bestDistSq)
{
bestDistSq = dTail;
bestIdx = i;
bestReverse = true;
}
}
}
var pick = pool[bestIdx];
pool.RemoveAt(bestIdx);
if (bestReverse)
pick.Reverse();
ordered.Add(pick);
current = pick[pick.Count - 1];
}
return ordered;
}
/// <summary>
/// Convenience: stitch then reorder.
/// </summary>
public static List<List<Vector>> Prepare(
IEnumerable<IReadOnlyList<Vector>> polylines,
double stitchTolerance = DefaultStitchTolerance,
bool allowReverse = true,
Vector? origin = null)
{
var stitched = Stitch(polylines, stitchTolerance);
return Reorder(stitched, allowReverse, origin);
}
private static bool Near(Vector a, Vector b, double tol)
{
var dx = a.X - b.X;
var dy = a.Y - b.Y;
return (dx * dx + dy * dy) <= tol * tol;
}
private static double SquaredDistance(Vector a, Vector b)
{
var dx = a.X - b.X;
var dy = a.Y - b.Y;
return dx * dx + dy * dy;
}
}
}