From 191f724631e50b50f94b8ae227752fb07ed7fac3 Mon Sep 17 00:00:00 2001
From: Leland Lucius <github@homerow.net>
Date: Wed, 29 Apr 2020 08:48:16 -0500
Subject: [PATCH] Bug 2406 - Mac: (Catalina) No transparency in docking-icon.

Backported upstream fix for:

https://trac.wxwidgets.org/ticket/18257
---
 src/osx/cocoa/nonownedwnd.mm |  6 ------
 src/osx/cocoa/window.mm      | 13 ++++++++++++-
 src/osx/nonownedwnd_osx.cpp  |  9 ++++++++-
 3 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/src/osx/cocoa/nonownedwnd.mm b/src/osx/cocoa/nonownedwnd.mm
index 9291601699..76d8b30157 100644
--- a/src/osx/cocoa/nonownedwnd.mm
+++ b/src/osx/cocoa/nonownedwnd.mm
@@ -739,12 +739,6 @@ long style, long extraStyle, const wxString& WXUNUSED(name) )
 
     [m_macWindow setDelegate:controller];
 
-    if ( ( style & wxFRAME_SHAPED) )
-    {
-        [m_macWindow setOpaque:NO];
-        [m_macWindow setAlphaValue:1.0];
-    }
-    
     if ( !(style & wxFRAME_TOOL_WINDOW) )
         [m_macWindow setHidesOnDeactivate:NO];
 }
diff --git a/src/osx/cocoa/window.mm b/src/osx/cocoa/window.mm
index a298a1abc5..f181021128 100644
--- a/src/osx/cocoa/window.mm
+++ b/src/osx/cocoa/window.mm
@@ -4984,7 +4984,15 @@ void wxWidgetCocoaImpl::SetBackgroundColour( const wxColour &col )
 
     if ( [targetView respondsToSelector:@selector(setBackgroundColor:) ] )
     {
-        [targetView setBackgroundColor: col.OSXGetNSColor()];
+        wxWindow* peer = GetWXPeer();
+        if ( peer->GetBackgroundStyle() != wxBG_STYLE_TRANSPARENT )
+        {
+            wxTopLevelWindow* toplevel = wxDynamicCast(peer,wxTopLevelWindow);
+
+            if ( toplevel == NULL || toplevel->GetShape().IsEmpty() )
+                [targetView setBackgroundColor:
+                        col.IsOk() ? col.OSXGetNSColor() : nil];
+        }
     }
 }
 
@@ -4995,6 +5003,9 @@ bool wxWidgetCocoaImpl::SetBackgroundStyle( wxBackgroundStyle style )
     if ( [m_osxView respondsToSelector:@selector(setOpaque:) ] )
     {
         [m_osxView setOpaque: opaque];
+
+        if ( style == wxBG_STYLE_TRANSPARENT )
+            [m_osxView setBackgroundColor:[NSColor clearColor]];
     }
     
     return true ;
diff --git a/src/osx/nonownedwnd_osx.cpp b/src/osx/nonownedwnd_osx.cpp
index d14c023855..7e9ca9c84f 100644
--- a/src/osx/nonownedwnd_osx.cpp
+++ b/src/osx/nonownedwnd_osx.cpp
@@ -256,7 +256,10 @@ bool wxNonOwnedWindow::SetBackgroundColour(const wxColour& c )
     if ( !wxWindow::SetBackgroundColour(c) && m_hasBgCol )
         return false ;
 
-    if ( GetBackgroundStyle() != wxBG_STYLE_CUSTOM )
+    // only set the native background color if the toplevel window's
+    // background is not supposed to be transparent, otherwise the
+    // transparency is lost
+    if ( GetBackgroundStyle() != wxBG_STYLE_PAINT && GetBackgroundStyle() != wxBG_STYLE_TRANSPARENT)
     {
         if ( m_nowpeer )
             return m_nowpeer->SetBackgroundColour(c);
@@ -511,6 +514,10 @@ bool wxNonOwnedWindow::DoSetRegionShape(const wxRegion& region)
 {
     m_shape = region;
 
+    // set the native content view to transparency, this is an implementation detail
+    // no reflected in the wx BackgroundStyle
+    GetPeer()->SetBackgroundStyle(wxBG_STYLE_TRANSPARENT);
+
     return m_nowpeer->SetShape(region);
 }