From a0f924191e8ca383c2500aa0a72fd7693e534099 Mon Sep 17 00:00:00 2001
From: Stefan Csomor <csomor@advancedconcepts.ch>
Date: Sat, 9 Sep 2017 19:32:18 +0200
Subject: [PATCH] Fixing vertical mirrored drawing for overlay on macos

---
 src/osx/cocoa/overlay.mm | 34 ++++++++++++++++++----------------
 1 file changed, 18 insertions(+), 16 deletions(-)

diff --git a/src/osx/cocoa/overlay.mm b/src/osx/cocoa/overlay.mm
index 4e7697edc2..05e4695978 100644
--- a/src/osx/cocoa/overlay.mm
+++ b/src/osx/cocoa/overlay.mm
@@ -114,21 +114,6 @@ void wxOverlayImpl::Init( wxDC* dc, int x , int y , int width , int height )
     wxASSERT_MSG(m_overlayWindow != NULL, _("Couldn't create the overlay window"));
     m_overlayContext = (CGContextRef) [[m_overlayWindow graphicsContext] graphicsPort];
     wxASSERT_MSG(  m_overlayContext != NULL , _("Couldn't init the context on the overlay window") );
-    
-    int ySize = 0;
-    if ( m_window )
-    {
-        ySize = m_height;
-    }
-    else
-    {
-        CGRect cgbounds ;
-        cgbounds = CGDisplayBounds(CGMainDisplayID());
-        ySize = cgbounds.size.height;
-    }
-
-    CGContextTranslateCTM(m_overlayContext, 0, ySize);
-    CGContextScaleCTM(m_overlayContext, 1, -1);
 }
 
 void wxOverlayImpl::BeginDrawing( wxDC* dc)
@@ -137,7 +122,24 @@ void wxOverlayImpl::BeginDrawing( wxDC* dc)
     wxGCDCImpl *win_impl = wxDynamicCast(impl,wxGCDCImpl);
     if (win_impl)
     {
-        win_impl->SetGraphicsContext( wxGraphicsContext::CreateFromNative( m_overlayContext ) );
+        int ySize = 0;
+        if ( m_window )
+        {
+            ySize = m_height;
+        }
+        else
+        {
+            CGRect cgbounds ;
+            cgbounds = CGDisplayBounds(CGMainDisplayID());
+            ySize = cgbounds.size.height;
+        }
+
+        wxGraphicsContext* ctx = wxGraphicsContext::CreateFromNative( m_overlayContext );
+        ctx->Translate(0, ySize);
+        ctx->Scale(1,-1);
+        
+        win_impl->SetGraphicsContext( ctx );
+        
         if (m_window)
             dc->SetDeviceOrigin(dc->LogicalToDeviceX(-m_x), dc->LogicalToDeviceY(-m_y));
         dc->SetClippingRegion(m_x, m_y, m_width, m_height);