From 3fcc5cdfc6a80c2743a019e9a661fbff487e513a Mon Sep 17 00:00:00 2001
From: stefan schippers <stefan.schippers@gmail.com>
Date: Thu, 30 Oct 2025 01:12:11 +0100
Subject: [PATCH] fix find_closest_arc() and arc_bbox() if arc was saved with
 negative "b" angle

---
 src/draw.c    | 15 +++++++++++++--
 src/findnet.c | 18 ++++++++++++++----
 2 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/src/draw.c b/src/draw.c
index b92d4906..4b86c21f 100644
--- a/src/draw.c
+++ b/src/draw.c
@@ -1934,8 +1934,19 @@ void arc_bbox(double x, double y, double r, double a, double b,
     *by2 = y+r;
     return;
   }
-  a = fmod(a, 360.);
-  if(a<0) a+=360.;
+
+  if(b < 0.) {
+    double aa = a;
+    a = fmod(aa + b, 360.);
+    if(a < 0)  a +=  360.;
+    b = fmod(aa, 360.);
+    if(b < 0) b += 360.;
+  } else {
+    b = fmod(a + b, 360.);
+    if(b < 0)  b += 360.;
+    a = fmod(a, 360.);
+    if(a < 0) a += 360.;
+  }
   aa = (int)(ceil(a/90.))*90;
   bb = (int)(floor((a+b)/90.))*90;
 
diff --git a/src/findnet.c b/src/findnet.c
index 9266f236..2ff10292 100644
--- a/src/findnet.c
+++ b/src/findnet.c
@@ -351,9 +351,19 @@ static void find_closest_arc(double mx, double my, int override_lock)
     dist *= dist; /* square d */
     angle = fmod(atan2(xctx->arc[c][i].y-my, mx-xctx->arc[c][i].x)*180./XSCH_PI, 360.);
     if(angle<0.) angle +=360.;
-    angle1 = xctx->arc[c][i].a;
-    angle2 = fmod(xctx->arc[c][i].a + xctx->arc[c][i].b, 360.);
-
+      angle1 = xctx->arc[c][i].a;
+      angle2 = fmod(xctx->arc[c][i].a + xctx->arc[c][i].b, 360.);
+    if(xctx->arc[c][i].b < 0) {
+      angle1 = fmod(xctx->arc[c][i].a + xctx->arc[c][i].b, 360.);
+      if(angle1 < 0.) angle1 += 360.;
+      angle2 = fmod(xctx->arc[c][i].a, 360.);
+      if(angle2 < 0.) angle2 += 360.;
+    } else {
+      angle1 = fmod(xctx->arc[c][i].a, 360.);
+      if(angle1 < 0.) angle1 += 360.;
+      angle2 = fmod(xctx->arc[c][i].a + xctx->arc[c][i].b, 360.);
+      if(angle2 < 0.) angle2 += 360.;
+    }
     match=0;
     if(dist < d) {
       if(xctx->arc[c][i].b==360.) match=1;
@@ -367,7 +377,7 @@ static void find_closest_arc(double mx, double my, int override_lock)
         }
       }
     }
-    dbg(1, "find_closest_arc(): dist = %g, angle = %g\n", dist, angle);
+    dbg(1, "find_closest_arc(): dist = %g, angle = %g, angle1=%g, angle2=%g\n", dist, angle, angle1, angle2);
     dbg(1, "find_closest_arc(): center=%g, %g: mouse: %g:%g\n",
                              xctx->arc[c][i].x, xctx->arc[c][i].y, mx, my);
     if(match ) {