Use arc mid point for footprint library parity DRC testing.

The arc center is a pseudo coordinate which is calculated for drawing
purposes.  This mid point is fixed unless the arc is modified which
should result in more reliable arc parity footprint library DRC testing.

Also change EDA_SHAPE::Compare() to use the arc mid point.

Fixes https://gitlab.com/kicad/code/kicad/-/issues/15917

common/eda_shape.cpp

@@ -2147,7 +2147,7 @@ int EDA_SHAPE::Compare( const EDA_SHAPE* aOther ) const
 
     if( m_shape == SHAPE_T::ARC )
     {
-        TEST_PT( m_arcCenter, aOther->m_arcCenter );
+        TEST_PT( GetArcMid(), aOther->GetArcMid() );
     }
     else if( m_shape == SHAPE_T::BEZIER )
     {

pcbnew/drc/drc_test_provider_library_parity.cpp

@@ -161,7 +161,7 @@ bool primitiveNeedsUpdate( const std::shared_ptr<PCB_SHAPE>& a,
 
         // Arc center is calculated and so may have round-off errors when parents are
         // differentially rotated.
-        if( ( a->GetCenter() - b->GetCenter() ).EuclideanNorm() > pcbIUScale.mmToIU( 0.0005 ) )
+        if( ( a->GetArcMid() - b->GetArcMid() ).EuclideanNorm() > pcbIUScale.mmToIU( 0.0005 ) )
             return true;
 
         break;
@@ -448,7 +448,7 @@ bool shapeNeedsUpdate( const PCB_SHAPE& curr_shape, const PCB_SHAPE& ref_shape )
 
         // Arc center is calculated and so may have round-off errors when parents are
         // differentially rotated.
-        if( ( curr_shape.GetCenter() - ref_shape.GetCenter() ).EuclideanNorm() > pcbIUScale.mmToIU( 0.0005 ) )
+        if( ( curr_shape.GetArcMid() - ref_shape.GetArcMid() ).EuclideanNorm() > pcbIUScale.mmToIU( 0.0005 ) )
             return true;
 
         break;

qa/data/config/9.99/kicad_common.json

@@ -90,6 +90,6 @@
     "pdf_viewer_name": "",
     "text_editor": "/usr/bin/open -e",
     "use_system_pdf_viewer": true,
-    "working_dir": "/home/mike/Projects/src/kicad/qa/tests"
+    "working_dir": "/home/wayne/src/kicad/qa/tests"
   }
 }