From bf9c1da41031e5d43ffcfd1dc1c5b809c2cf871a Mon Sep 17 00:00:00 2001
From: Adrian Mariano <avm4@cornell.edu>
Date: Wed, 22 May 2024 20:26:52 -0400
Subject: [PATCH 1/3] arc endpoint bugfix

---
 drawing.scad | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/drawing.scad b/drawing.scad
index 1a2b579..9b914b9 100644
--- a/drawing.scad
+++ b/drawing.scad
@@ -771,10 +771,12 @@ function arc(n, r, angle, d, cp, points, corner, width, thickness, start, wedge=
         assert(is_def(r) && r>0, "Arc radius invalid")
         let(
             n = is_def(n) ? n : max(3, ceil(segs(r)*abs(angle)/360)),
-            arcpoints = [for(i=[0:n-1]) let(theta = start + i*angle/(n-1)) r*[cos(theta),sin(theta)]+cp],
-            extra = wedge? [cp] : []
+            arcpoints = [for(i=[0:n-1]) let(theta = start + i*angle/(n-1)) r*[cos(theta),sin(theta)]+cp]
         )
-        concat(extra,arcpoints)
+        [
+          if (wedge) cp,
+          each arcpoints
+        ]
   : is_def(corner)? 
         assert(is_path(corner,[2,3]) && len(corner)==3,str("Point list is invalid"))
         assert(is_undef(cp) && !any([long,cw,ccw]), "Cannot use cp, long, cw, or ccw with corner")
@@ -849,9 +851,17 @@ function arc(n, r, angle, d, cp, points, corner, width, thickness, start, wedge=
             theta_start = atan2(points[0].y-cp.y, points[0].x-cp.x),
             theta_end = atan2(points[1].y-cp.y, points[1].x-cp.x),
             angle = posmod(theta_end-theta_start, 360),
-            arcpts = arc(n,cp=cp,r=r,start=theta_start,angle=angle,wedge=wedge)
+            // Specify endpoints exactly; skip those endpoints when producing arc points
+            arcpts = [ if (wedge) cp, 
+                       points[0],
+                       each arc(n,cp=cp,r=r,start=theta_start+angle/(n+1),angle=angle-2*angle/(n+1)),
+                       points[1]
+                     ]
+                                           
         )
-        dir ? arcpts : wedge?reverse_polygon(arcpts):reverse(arcpts);
+        dir ? arcpts
+            : wedge ? reverse_polygon(arcpts)
+                    : reverse(arcpts);
 
 
 module arc(n, r, angle, d, cp, points, corner, width, thickness, start, wedge=false, anchor=CENTER, spin=0)

From f3b35eab0a087fc396d7ce8dc257a640f8eae4e8 Mon Sep 17 00:00:00 2001
From: Adrian Mariano <avm4@cornell.edu>
Date: Wed, 22 May 2024 21:30:36 -0400
Subject: [PATCH 2/3] arc bugfix

---
 drawing.scad | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drawing.scad b/drawing.scad
index 9b914b9..6edae99 100644
--- a/drawing.scad
+++ b/drawing.scad
@@ -854,7 +854,7 @@ function arc(n, r, angle, d, cp, points, corner, width, thickness, start, wedge=
             // Specify endpoints exactly; skip those endpoints when producing arc points
             arcpts = [ if (wedge) cp, 
                        points[0],
-                       each arc(n,cp=cp,r=r,start=theta_start+angle/(n+1),angle=angle-2*angle/(n+1)),
+                       each arc(n-2,cp=cp,r=r,start=theta_start+angle/(n-1),angle=angle-2*angle/(n-1)),
                        points[1]
                      ]
                                            

From 04437cc6a00d448708f4fd40efd7a8de5c3008df Mon Sep 17 00:00:00 2001
From: Adrian Mariano <avm4@cornell.edu>
Date: Wed, 22 May 2024 21:51:01 -0400
Subject: [PATCH 3/3] bugfix

---
 drawing.scad | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drawing.scad b/drawing.scad
index 6edae99..1771188 100644
--- a/drawing.scad
+++ b/drawing.scad
@@ -852,15 +852,17 @@ function arc(n, r, angle, d, cp, points, corner, width, thickness, start, wedge=
             theta_end = atan2(points[1].y-cp.y, points[1].x-cp.x),
             angle = posmod(theta_end-theta_start, 360),
             // Specify endpoints exactly; skip those endpoints when producing arc points
+            // Generating the whole arc and clipping ends is the easiest way to ensure that we
+            // generate the proper number of points.  
             arcpts = [ if (wedge) cp, 
                        points[0],
-                       each arc(n-2,cp=cp,r=r,start=theta_start+angle/(n-1),angle=angle-2*angle/(n-1)),
+                       each select(arc(n,cp=cp,r=r,start=theta_start,angle=angle),1,-2),
                        points[1]
                      ]
                                            
         )
         dir ? arcpts
-            : wedge ? reverse_polygon(arcpts)
+            : wedge ? reverse_polygon(arcpts)   // Keep the centerpoint at position 0 in the list
                     : reverse(arcpts);