Fix issues in DXF import and GFX import dialog

Fixes: lp:1812840
https://bugs.launchpad.net/kicad/+bug/1812840

pcbnew/import_gfx/dialog_import_gfx.cpp

@@ -476,8 +476,11 @@ bool InvokeDialogImportGfxModule( PCB_BASE_FRAME* aCaller, MODULE* aModule )
 
 void DIALOG_IMPORT_GFX::originOptionOnUpdateUI( wxUpdateUIEvent& event )
 {
-    m_rbInteractivePlacement->SetValue( m_placementInteractive );
-    m_rbAbsolutePlacement->SetValue( not m_placementInteractive );
+    if( m_rbInteractivePlacement->GetValue() != m_placementInteractive )
+        m_rbInteractivePlacement->SetValue( m_placementInteractive );
+
+    if( m_rbAbsolutePlacement->GetValue() == m_placementInteractive )
+        m_rbAbsolutePlacement->SetValue( not m_placementInteractive );
 
     m_DxfPcbPositionUnits->Enable( not m_placementInteractive );
     m_DxfPcbXCoord->Enable( not m_placementInteractive );

pcbnew/import_gfx/dxf_import_plugin.cpp

@@ -321,12 +321,12 @@ void DXF_IMPORT_PLUGIN::addArc( const DL_ArcData& aData )
     double arcStarty = 0;
 
     // aData.anglex is in degrees. Our internal units are 0.1 degree
-    // so convert DXF angles to our units
+    // so convert DXF angles (in degrees) to our units
     #define DXF2ANGLEUI 10
     double  startangle = aData.angle1 * DXF2ANGLEUI;
     double  endangle = aData.angle2 * DXF2ANGLEUI;
 
-    RotatePoint( &arcStartx, &arcStarty, -RAD2DECIDEG( startangle ) );
+    RotatePoint( &arcStartx, &arcStarty, -startangle );
     VECTOR2D arcStart( mapX( arcStartx + aData.cx ), mapY( arcStarty + aData.cy ) );
 
     // calculate arc angle (arcs are CCW, and should be < 0 in Pcbnew)