# HG changeset patch
# User Sebastien Jodogne <s.jodogne@gmail.com>
# Date 1670003051 -3600
# Node ID abd4ee1648de906e43c790e985419e5b906ec152
# Parent  25d269c7b7535591e8accaf78461bd8f6fb3bca8
Fix measurement of arcs

diff -r 25d269c7b753 -r abd4ee1648de Applications/StoneWebViewer/NEWS
--- a/Applications/StoneWebViewer/NEWS	Fri Dec 02 18:06:33 2022 +0100
+++ b/Applications/StoneWebViewer/NEWS	Fri Dec 02 18:44:11 2022 +0100
@@ -2,6 +2,7 @@
 ===============================
 
 * Annotations are grouped into one submenu for narrow screens
+* Fix measurement of arcs
 
 
 Version 2.4 (2022-11-02)
diff -r 25d269c7b753 -r abd4ee1648de OrthancStone/Sources/Scene2D/AnnotationsSceneLayer.cpp
--- a/OrthancStone/Sources/Scene2D/AnnotationsSceneLayer.cpp	Fri Dec 02 18:06:33 2022 +0100
+++ b/OrthancStone/Sources/Scene2D/AnnotationsSceneLayer.cpp	Fri Dec 02 18:44:11 2022 +0100
@@ -653,21 +653,34 @@
       const double yc = middle_.GetY();
       const double x2 = end_.GetX();
       const double y2 = end_.GetY();
-        
-      startAngle = atan2(y1 - yc, x1 - xc);
-      endAngle = atan2(y2 - yc, x2 - xc);
-
-      fullAngle = endAngle - startAngle;
-        
-      while (fullAngle < -PI)
+
+      double referenceAngle = atan2(y1 - yc, x1 - xc);
+      double secondAngle = atan2(y2 - yc, x2 - xc);
+
+      secondAngle -= referenceAngle;
+
+      while (secondAngle >= PI)
+      {
+        secondAngle -= 2.0 * PI;
+      }
+
+      while (secondAngle <= -PI)
       {
-        fullAngle += 2.0 * PI;
+        secondAngle += 2.0 * PI;
+      }
+
+      if (secondAngle < 0)
+      {
+        startAngle = referenceAngle + secondAngle;
+        endAngle = referenceAngle;
       }
-        
-      while (fullAngle >= PI)
+      else
       {
-        fullAngle -= 2.0 * PI;
+        startAngle = referenceAngle;
+        endAngle = referenceAngle + secondAngle;
       }
+      
+      fullAngle = endAngle - startAngle;
     }
       
   public: