Fixed a minor bug in RectClip (#597)

AngusJohnson · AngusJohnson · commit 6222af46c73a · 2023-08-06T12:56:30.000+10:00
Fixed a minor bug in merging solution polygons (#606)
diff --git a/CPP/Clipper2Lib/src/clipper.engine.cpp b/CPP/Clipper2Lib/src/clipper.engine.cpp
@@ -2499,7 +2499,6 @@ namespace Clipper2Lib {
 #endif
       AddTrialHorzJoin(op);
     }
-    OutRec* currHorzOutrec = horz.outrec;
 
     while (true) // loop through consec. horizontal edges
     {
@@ -2579,9 +2578,8 @@ namespace Clipper2Lib {
           e = horz.prev_in_ael;
         }
 
-        if (horz.outrec && horz.outrec != currHorzOutrec)
+        if (horz.outrec)
         {
-          currHorzOutrec = horz.outrec;
           //nb: The outrec containining the op returned by IntersectEdges
           //above may no longer be associated with horzEdge.
           AddTrialHorzJoin(GetLastOp(horz));
diff --git a/CPP/Clipper2Lib/src/clipper.rectclip.cpp b/CPP/Clipper2Lib/src/clipper.rectclip.cpp
@@ -1,6 +1,6 @@
 /*******************************************************************************
 * Author    :  Angus Johnson                                                   *
-* Date      :  16 July 2023                                                    *
+* Date      :  6 August 2023                                                   *
 * Website   :  http://www.angusj.com                                           *
 * Copyright :  Angus Johnson 2010-2023                                         *
 * Purpose   :  FAST rectangular clipping                                       *
@@ -474,7 +474,7 @@ namespace Clipper2Lib {
         // intersect pt but we'll also need the first intersect pt (ip2)
         loc = prev;
         GetIntersection(rect_as_path_, prev_pt, path[i], loc, ip2);
-        if (crossing_prev != Location::Inside)
+        if (crossing_prev != Location::Inside && crossing_prev != loc) //579
           AddCorner(crossing_prev, loc);
 
         if (first_cross_ == Location::Inside)
diff --git a/CPP/Tests/TestRectClip.cpp b/CPP/Tests/TestRectClip.cpp
@@ -55,4 +55,15 @@ TEST(Clipper2Tests, TestRectClip)
   EXPECT_EQ(solBounds.Width(), rect.Width());
   EXPECT_EQ(solBounds.Height(), rect.Height());
 
+}
+
+TEST(Clipper2Tests, TestRectClip2) //#597
+{
+  Clipper2Lib::Rect64 rect(54690, 0, 65628, 6000);
+  Clipper2Lib::Paths64 subject {{{700000, 6000}, { 0, 6000 }, { 0, 5925 }, { 700000, 5925 }}};
+
+  Clipper2Lib::Paths64 solution = Clipper2Lib::RectClip(rect, subject);
+
+  //std::cout << solution << std::endl;
+  EXPECT_TRUE(solution.size() == 1 && solution[0].size() == 4);
 }
diff --git a/CSharp/Clipper2Lib/Clipper.Engine.cs b/CSharp/Clipper2Lib/Clipper.Engine.cs
@@ -1,6 +1,6 @@
 ﻿/*******************************************************************************
 * Author    :  Angus Johnson                                                   *
-* Date      :  26 July 2023                                                    *
+* Date      :  6 August 2023                                                   *
 * Website   :  http://www.angusj.com                                           *
 * Copyright :  Angus Johnson 2010-2023                                         *
 * Purpose   :  This is the main polygon clipping module                        *
@@ -2173,7 +2173,6 @@ private void DoHorizontal(Active horz)
 #endif
         AddToHorzSegList(op);
       }
-      OutRec? currOutrec = horz.outrec!;
 
       for (; ; )
       {
@@ -2248,11 +2247,8 @@ private void DoHorizontal(Active horz)
             ae = horz.prevInAEL;
           }
 
-          if (IsHotEdge(horz) && (horz.outrec != currOutrec))
-          {
-            currOutrec = horz.outrec;
+          if (IsHotEdge(horz))
             AddToHorzSegList(GetLastOp(horz));
-          }
 
         } // we've reached the end of this horizontal
 
diff --git a/CSharp/Clipper2Lib/Clipper.RectClip.cs b/CSharp/Clipper2Lib/Clipper.RectClip.cs
@@ -1,6 +1,6 @@
 ﻿/*******************************************************************************
 * Author    :  Angus Johnson                                                   *
-* Date      :  30 May 2023                                                     *
+* Date      :  6 August 2023                                                   *
 * Website   :  http://www.angusj.com                                           *
 * Copyright :  Angus Johnson 2010-2023                                         *
 * Purpose   :  FAST rectangular clipping                                       *
@@ -544,7 +544,7 @@ private void ExecuteInternal(Path64 path)
           loc = prev;
           GetIntersection(rectPath_, 
             prevPt, path[i], ref loc, out Point64 ip2);
-          if (prevCrossLoc != Location.inside)
+          if (prevCrossLoc != Location.inside && prevCrossLoc != loc) //#597
             AddCorner(prevCrossLoc, loc);
 
           if (firstCross == Location.inside)
diff --git a/Delphi/Clipper2Lib/Clipper.Engine.pas b/Delphi/Clipper2Lib/Clipper.Engine.pas
@@ -2,7 +2,7 @@
 
 (*******************************************************************************
 * Author    :  Angus Johnson                                                   *
-* Date      :  26 July 2023                                                    *
+* Date      :  6 August 2023                                                   *
 * Website   :  http://www.angusj.com                                           *
 * Copyright :  Angus Johnson 2010-2023                                         *
 * Purpose   :  This is the main polygon clipping module                        *
@@ -3401,7 +3401,6 @@ procedure TClipperBase.DoHorizontal(horzEdge: PActive);
   e: PActive;
   pt: TPoint64;
   op: POutPt;
-  currOr: POutRec;
   isLeftToRight, horzIsOpen: Boolean;
 begin
 (*******************************************************************************
@@ -3443,7 +3442,6 @@ procedure TClipperBase.DoHorizontal(horzEdge: PActive);
   {$ENDIF}
     FHorzSegList.Add(op);
   end;
-  currOr := horzEdge.outrec;
 
   while true do // loop through consec. horizontal edges
   begin
@@ -3520,9 +3518,8 @@ procedure TClipperBase.DoHorizontal(horzEdge: PActive);
         horzEdge.currX := e.currX;
         e := horzEdge.prevInAEL;
       end;
-      if IsHotEdge(horzEdge) and (horzEdge.outrec <> currOr) then
+      if IsHotEdge(horzEdge) then
       begin
-        currOr := horzEdge.outrec;
         //nb: The outrec containining the op returned by IntersectEdges
         //above may no longer be associated with horzEdge.
         FHorzSegList.Add(GetLastOp(horzEdge));
diff --git a/Delphi/Clipper2Lib/Clipper.RectClip.pas b/Delphi/Clipper2Lib/Clipper.RectClip.pas
@@ -2,7 +2,7 @@
 
 (*******************************************************************************
 * Author    :  Angus Johnson                                                   *
-* Date      :  30 May 2023                                                     *
+* Date      :  6 August 2023                                                   *
 * Website   :  http://www.angusj.com                                           *
 * Copyright :  Angus Johnson 2010-2023                                         *
 * Purpose   :  FAST rectangular clipping                                       *
@@ -700,7 +700,7 @@ procedure TRectClip64.ExecuteInternal(const path: TPath64);
       // intersect pt but we'll also need the first intersect pt (ip2)
       loc := prevLoc;
       GetIntersection(fRectPath, prevPt, path[i], loc, ip2);
-      if (prevCrossLoc <> locInside) then
+      if (prevCrossLoc <> locInside) and (prevCrossLoc <> loc) then //#579
         AddCorner(prevCrossLoc, loc);
 
       if (firstCrossLoc = locInside) then

Original file line number	Diff line number	Diff line change
`@@ -2499,7 +2499,6 @@ namespace Clipper2Lib {`
`2499`	`2499`	`#endif`
`2500`	`2500`	`AddTrialHorzJoin(op);`
`2501`	`2501`	`}`
`2502`		`- OutRec* currHorzOutrec = horz.outrec;`
`2503`	`2502`
`2504`	`2503`	`while (true) // loop through consec. horizontal edges`
`2505`	`2504`	`{`
`@@ -2579,9 +2578,8 @@ namespace Clipper2Lib {`
`2579`	`2578`	`e = horz.prev_in_ael;`
`2580`	`2579`	`}`
`2581`	`2580`
`2582`		`- if (horz.outrec && horz.outrec != currHorzOutrec)`
	`2581`	`+ if (horz.outrec)`
`2583`	`2582`	`{`
`2584`		`- currHorzOutrec = horz.outrec;`
`2585`	`2583`	`//nb: The outrec containining the op returned by IntersectEdges`
`2586`	`2584`	`//above may no longer be associated with horzEdge.`
`2587`	`2585`	`AddTrialHorzJoin(GetLastOp(horz));`