From 4e5dd6952e5f2351bb03ad63fab4e74ea6b19da9 Mon Sep 17 00:00:00 2001
From: Jeff Young <jeff@rokeby.ie>
Date: Sun, 1 Nov 2020 15:25:42 +0000
Subject: [PATCH] Fix arc flipping behaviour.

Also fixes flipping of a dragged selection to be around the anchor
point.

Fixes https://gitlab.com/kicad/code/kicad/issues/6217
---
 pcbnew/pcb_shape.cpp       | 11 ++++++++++-
 pcbnew/tools/edit_tool.cpp | 11 ++++++++---
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/pcbnew/pcb_shape.cpp b/pcbnew/pcb_shape.cpp
index c6b758860d..34b57a2f39 100644
--- a/pcbnew/pcb_shape.cpp
+++ b/pcbnew/pcb_shape.cpp
@@ -4,7 +4,7 @@
  * Copyright (C) 2018 Jean-Pierre Charras, jp.charras at wanadoo.fr
  * Copyright (C) 2012 SoftPLC Corporation, Dick Hollenbeck <dick@softplc.com>
  * Copyright (C) 2011 Wayne Stambaugh <stambaughw@verizon.net>
- * Copyright (C) 1992-2019 KiCad Developers, see AUTHORS.txt for contributors.
+ * Copyright (C) 1992-2020 KiCad Developers, see AUTHORS.txt for contributors.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -165,6 +165,10 @@ void PCB_SHAPE::Scale( double aScale )
         scalePt( m_BezierC2 );
         break;
 
+    case S_ARC:
+        scalePt( m_ThirdPoint );
+        break;
+
     case S_CIRCLE:          //  ring or circle
         m_End.x = m_Start.x + KiROUND( radius * aScale );
         m_End.y = m_Start.y;
@@ -261,6 +265,11 @@ void PCB_SHAPE::Flip( const wxPoint& aCentre, bool aFlipLeftRight )
     switch ( m_Shape )
     {
     case S_ARC:
+        if( aFlipLeftRight )
+            m_ThirdPoint.x   = aCentre.x - ( m_ThirdPoint.x - aCentre.x );
+        else
+            m_ThirdPoint.y   = aCentre.y - ( m_ThirdPoint.y - aCentre.y );
+
         m_Angle = -m_Angle;
         break;
 
diff --git a/pcbnew/tools/edit_tool.cpp b/pcbnew/tools/edit_tool.cpp
index 0f9ded1dc9..86feb53f6b 100644
--- a/pcbnew/tools/edit_tool.cpp
+++ b/pcbnew/tools/edit_tool.cpp
@@ -1158,10 +1158,15 @@ int EDIT_TOOL::Flip( const TOOL_EVENT& aEvent )
     // Flip around the anchor for footprints, and the bounding box center for board items
     VECTOR2I modPoint = EditingModules() ? VECTOR2I( 0, 0 ) : selection.GetCenter();
 
-    // If only one item selected, flip around the item anchor point, instead
-    // of the bounding box center, to avoid moving the item anchor
+    // If only one item selected, flip around the selection or item anchor point (instead
+    // of the bounding box center) to avoid moving the item anchor
     if( selection.GetSize() == 1 )
-        modPoint = static_cast<BOARD_ITEM*>( selection.GetItem( 0 ) )->GetPosition();
+    {
+        if( selection.HasReferencePoint() )
+            modPoint = selection.GetReferencePoint();
+        else
+            modPoint = static_cast<BOARD_ITEM*>( selection.GetItem( 0 ) )->GetPosition();
+    }
 
     bool leftRight = frame()->Settings().m_FlipLeftRight;