Further fixes to Polytree nesting (#590)

CPP/Clipper2Lib/src/clipper.engine.cpp

@@ -1,6 +1,6 @@
 /*******************************************************************************
 * Author    :  Angus Johnson                                                   *
-* Date      :  16 July 2023                                                    *
+* Date      :  19 July 2023                                                    *
 * Website   :  http://www.angusj.com                                           *
 * Copyright :  Angus Johnson 2010-2023                                         *
 * Purpose   :  This is the main polygon clipping module                        *
@@ -2842,7 +2842,8 @@ namespace Clipper2Lib {
   {
     for (auto split : *splits)
     {
-      if(split == outrec || split == outrec->owner) continue;
+      split = GetRealOutRec(split);
+      if(!split || split == outrec || split == outrec->owner) continue;
       else if (split->splits && CheckSplitOwner(outrec, split->splits)) return true;
       else if (CheckBounds(split) && split->bounds.Contains(outrec->bounds) &&
         Path1InsidePath2(outrec->pts, split->pts))

CPP/Examples/VariableOffset/VariableOffset.cpp

@@ -39,11 +39,12 @@ void test1() {
   Paths64 solution;
   co.Execute(1.0, solution);
 
+  std::string filename = "test1.svg";
   SvgWriter svg;
   SvgAddOpenSubject(svg, subject, FillRule::NonZero);
   SvgAddSolution(svg, solution, FillRule::NonZero, false);
-  SvgSaveToFile(svg, "c:\\temp\\tmp1.svg", 400, 400);
-  System("c:\\temp\\tmp1.svg");
+  SvgSaveToFile(svg, filename, 400, 400);
+  System(filename);
 }
 
 void test2() {
@@ -68,11 +69,12 @@ void test2() {
   Paths64 solution;
   co.Execute(1.0, solution);
 
+  std::string filename = "test2.svg";
   SvgWriter svg;
   SvgAddOpenSubject(svg, subject, FillRule::NonZero);
   SvgAddSolution(svg, solution, FillRule::NonZero, false);
-  SvgSaveToFile(svg, "c:\\temp\\tmp2.svg", 400, 400);
-  System("c:\\temp\\tmp2.svg");
+  SvgSaveToFile(svg, filename, 400, 400);
+  System(filename);
 }
 
 void test3() {
@@ -95,11 +97,12 @@ void test3() {
   Paths64 solution;
   co.Execute(1.0, solution);
 
+  std::string filename = "test3.svg";
   SvgWriter svg;
   SvgAddSubject(svg, subject, FillRule::NonZero);
   SvgAddSolution(svg, solution, FillRule::NonZero, false);
-  SvgSaveToFile(svg, "c:\\temp\\tmp3.svg", 400, 400);
-  System("c:\\temp\\tmp3.svg");
+  SvgSaveToFile(svg, filename, 400, 400);
+  System(filename);
 }
 
 void test4() {
@@ -118,14 +121,36 @@ void test4() {
         //double vertex_angle = std::atan2(vertex_sin_a, vertex_cos_a);
         //double edge_angle = std::atan2(path_norms[curr_idx].y, path_norms[curr_idx].x);
         double sin_edge = path_norms[curr_idx].y;
-      return Sqr(sin_edge) * 3 * scale; }
+        return Sqr(sin_edge) * 3 * scale; }
   , solution);
 
+  std::string filename = "test4.svg";
   SvgWriter svg;
   SvgAddOpenSubject(svg, subject, FillRule::NonZero);
   SvgAddSolution(svg, solution, FillRule::NonZero, false);
-  SvgSaveToFile(svg, "c:\\temp\\tmp4.svg", 400, 400);
-  System("c:\\temp\\tmp4.svg");
+  SvgSaveToFile(svg, filename, 400, 400);
+  System(filename);
+}
+
+void test5() {
+
+  Paths64 solution;
+  Paths64 subject = { MakePath({0,0, 20,0, 40,0, 60,0, 80,0, 100,0}) };
+
+  ClipperOffset co;
+  co.AddPaths(subject, JoinType::Round, EndType::Butt);
+  co.Execute(
+    [](const Path64& path,
+      const PathD& path_norms, size_t curr_idx, size_t prev_idx) {
+        return double(curr_idx * curr_idx + 10); }
+  , solution);
+
+  SvgWriter svg;
+  std::string filename = "test5.svg";
+  SvgAddOpenSubject(svg, subject, FillRule::NonZero);
+  SvgAddSolution(svg, solution, FillRule::NonZero, false);
+  SvgSaveToFile(svg, filename, 400, 400);
+  System(filename);
 }
 
 
@@ -135,5 +160,6 @@ int main() {
   test2();
   test3();
   test4();
+  test5();
   return 0;
 }

CSharp/Clipper2Lib.Examples/InflateDemo/Main.cs

@@ -1,6 +1,6 @@
 /*******************************************************************************
 * Author    :  Angus Johnson                                                   *
-* Date      :  16 September 2022                                               *
+* Date      :  19 July 2023                                                    *
 * Website   :  http://www.angusj.com                                           *
 * Copyright :  Angus Johnson 2010-2022                                         *
 * License   :  http://www.boost.org/LICENSE_1_0.txt                            *
@@ -20,13 +20,14 @@ public static void Main()
     {
       DoSimpleShapes();
       DoRabbit();
+      DoVariableOffset();
     }
 
     public static void DoSimpleShapes()
     {
       //triangle offset - with large miter
       Paths64 p = new() { Clipper.MakePath(new int[] { 30, 150, 60, 350, 0, 350 }) };
-      Paths64 pp = new ();
+      Paths64 pp = new();
       pp.AddRange(p);
 
       for (int i = 0; i < 5; ++i)
@@ -42,18 +43,19 @@ public static void DoSimpleShapes()
       pp.AddRange(p);
       //nb: using the ClipperOffest class directly here to control 
       //different join types within the same offset operation
-      ClipperOffset co = new ();
+      ClipperOffset co = new();
       co.AddPaths(p, JoinType.Square, EndType.Joined);
       p = Clipper.TranslatePaths(p, 120, 100);
       pp.AddRange(p);
       co.AddPaths(p, JoinType.Round, EndType.Joined);
       co.Execute(20, p);
       pp.AddRange(p);
 
-      SvgWriter svg = new ();
+      string filename = "../../../inflate.svg";
+      SvgWriter svg = new();
       SvgUtils.AddSolution(svg, pp, false);
-      SvgUtils.SaveToFile(svg, "../../../inflate.svg", FillRule.EvenOdd, 800, 600, 20);
-      ClipperFileIO.OpenFileWithDefaultApp("../../../inflate.svg");
+      SvgUtils.SaveToFile(svg, filename, FillRule.EvenOdd, 800, 600, 20);
+      ClipperFileIO.OpenFileWithDefaultApp(filename);
     }
 
     public static void DoRabbit()
@@ -71,10 +73,11 @@ public static void DoRabbit()
         solution.AddRange(pd);
       }
 
+      string filename = "../../../rabbit.svg";
       SvgWriter svg = new ();
       SvgUtils.AddSolution(svg, solution, false);
-      SvgUtils.SaveToFile(svg, "../../../rabbit2.svg", FillRule.EvenOdd, 450, 720, 10);
-      ClipperFileIO.OpenFileWithDefaultApp("../../../rabbit2.svg");
+      SvgUtils.SaveToFile(svg, filename, FillRule.EvenOdd, 450, 720, 10);
+      ClipperFileIO.OpenFileWithDefaultApp(filename);
     }
 
     public static PathsD LoadPathsFromResource(string resourceName)
@@ -99,7 +102,25 @@ public static PathsD LoadPathsFromResource(string resourceName)
       }
       return result;
     }
-
+
+    public static void DoVariableOffset()
+    {
+      Paths64 p = new() { Clipper.MakePath(new int[] { 0,50, 20,50, 40,50, 60,50, 80,50, 100,50 }) };
+      Paths64 solution = new();
+      ClipperOffset co = new();
+      co.AddPaths(p, JoinType.Square, EndType.Butt);
+      co.Execute(
+        delegate (Path64 path, PathD path_norms, int currPt, int prevPt) 
+        { return currPt* currPt + 10; } , solution);
+
+      string filename = "../../../variable_offset.svg";
+      SvgWriter svg = new();
+      SvgUtils.AddOpenSubject(svg, p);
+      SvgUtils.AddSolution(svg, solution, true);
+      SvgUtils.SaveToFile(svg, filename, FillRule.EvenOdd, 500, 500, 60);
+      ClipperFileIO.OpenFileWithDefaultApp(filename);
+    }
+
   } //end Application
 
 } //namespace

CSharp/Clipper2Lib/Clipper.Engine.cs

@@ -1,6 +1,6 @@
 /*******************************************************************************
 * Author    :  Angus Johnson                                                   *
-* Date      :  16 July 2023                                                    *
+* Date      :  19 July 2023                                                    *
 * Website   :  http://www.angusj.com                                           *
 * Copyright :  Angus Johnson 2010-2023                                         *
 * Purpose   :  This is the main polygon clipping module                        *
@@ -3022,8 +3022,8 @@ private bool CheckSplitOwner(OutRec outrec, List<int>? splits)
     {
       foreach (int i in splits!)
       {
-        OutRec? split = _outrecList[i];
-        if (split == outrec || split == outrec.owner) continue;
+        OutRec? split = GetRealOutRec(_outrecList[i]);
+        if (split == null || split == outrec || split == outrec.owner) continue;
         if (split!.splits != null && CheckSplitOwner(outrec, split.splits)) return true;
         if (CheckBounds(split) && split.bounds.Contains(outrec.bounds) &&
             Path1InsidePath2(outrec.pts!, split.pts!))

Delphi/Clipper2Lib/Clipper.Engine.pas

@@ -2,7 +2,7 @@
 
 (*******************************************************************************
 * Author    :  Angus Johnson                                                   *
-* Date      :  16 July 2023                                                    *
+* Date      :  19 July 2023                                                    *
 * Website   :  http://www.angusj.com                                           *
 * Copyright :  Angus Johnson 2010-2023                                         *
 * Purpose   :  This is the main polygon clipping module                        *
@@ -3716,8 +3716,9 @@ function TClipperBase.CheckSplitOwner(outrec: POutRec; const splits: TOutRecArra
   Result := false;
   for i := 0 to High(splits) do
   begin
-    split := splits[i];
-    if (split = outrec) or (split = outrec.owner) then Continue
+    split := GetRealOutRec(splits[i]);
+    if not assigned(split) or (split = outrec) or (split = outrec.owner) then
+        Continue
     else if Assigned(split.splits) and
       CheckSplitOwner(outrec, split.splits) then
     begin