Render statusbar natively on macOS

Instead of trying to mimic native statusbar background rendering in our
own code, use NSWindow setContentBorderThickness:forEdge: to extend the
border that is drawn by the system. This is the canonical way of doing
statusbars ("bottom bar") in AppKit.

The text is still drawn generically, but that's a much smaller issue
than trying to match the border gradient.

include/wx/osx/cocoa/private.h

@@ -329,6 +329,8 @@ public :
 
     virtual void SetRepresentedFilename(const wxString& filename) wxOVERRIDE;
 
+    virtual void SetBottomBorderThickness(int thickness) wxOVERRIDE;
+
     wxNonOwnedWindow*   GetWXPeer() { return m_wxPeer; }
 
     CGWindowLevel   GetWindowLevel() const wxOVERRIDE { return m_macWindowLevel; }

include/wx/osx/core/private.h

@@ -984,6 +984,8 @@ public :
 
     virtual void SetRepresentedFilename(const wxString& WXUNUSED(filename)) { }
 
+    virtual void SetBottomBorderThickness(int WXUNUSED(thickness)) { }
+
 #if wxOSX_USE_IPHONE
     virtual CGFloat GetWindowLevel() const { return 0.0; }
 #else

include/wx/osx/frame.h

@@ -71,6 +71,8 @@ public:
                                            long style = wxSTB_DEFAULT_STYLE,
                                            wxWindowID id = 0,
                                            const wxString& name = wxASCII_STR(wxStatusLineNameStr)) wxOVERRIDE;
+
+    virtual void SetStatusBar(wxStatusBar *statbar) wxOVERRIDE;
 #endif // wxUSE_STATUSBAR
 
     void PositionBars();

include/wx/osx/statusbr.h

@@ -38,9 +38,7 @@ protected:
     virtual void InitColours() wxOVERRIDE;
 
 private:
-    wxColour m_textActive, m_textInactive,
+    wxColour m_textActive, m_textInactive;
-             m_bgActiveFrom, m_bgActiveTo,
-             m_borderActive, m_borderInactive;
 
     wxDECLARE_DYNAMIC_CLASS(wxStatusBarMac);
     wxDECLARE_EVENT_TABLE();

src/osx/carbon/frame.cpp

@@ -112,6 +112,12 @@ wxStatusBar *wxFrame::OnCreateStatusBar(int number, long style, wxWindowID id,
     return statusBar;
 }
 
+void wxFrame::SetStatusBar(wxStatusBar *statbar)
+{
+    wxFrameBase::SetStatusBar(statbar);
+    m_nowpeer->SetBottomBorderThickness(statbar ? WX_MAC_STATUSBAR_HEIGHT : 0);
+}
+
 void wxFrame::PositionStatusBar()
 {
     if (m_frameStatusBar && m_frameStatusBar->IsShown() )

src/osx/carbon/statbrma.cpp

@@ -78,42 +78,22 @@ void wxStatusBarMac::InitColours()
 {
     if ( WX_IS_MACOS_AVAILABLE(10, 14) )
     {
-        // FIXME: None of this is correct and is only very loose
-        //        approximation. 10.14's dark mode uses dynamic colors that
-        //        use desktop tinting. The only correct way to render the
-        //        statusbar is to use windowBackgroundColor in a NSBox.
-        wxColour bg = wxSystemSettings::GetColour(wxSYS_COLOUR_APPWORKSPACE);
-        m_textActive = wxSystemSettings::GetColour(wxSYS_COLOUR_BTNTEXT);
-        m_textInactive = wxSystemSettings::GetColour(wxSYS_COLOUR_GRAYTEXT);
-
         if ( wxSystemSettings::GetAppearance().IsDark() )
         {
-            // dark mode appearance
+            m_textActive = wxColour(0xA9, 0xA9, 0xA9);
-            m_textActive = wxColour(0xB0, 0xB0, 0xB0);
+            m_textInactive = wxColour(0x67, 0x67, 0x67);
-            m_bgActiveFrom = wxColour(0x32, 0x32, 0x34);
-            m_bgActiveTo = wxColour(0x29, 0x29, 0x2A);
-            m_borderActive = wxColour(0x00, 0x00, 0x00);
-            m_borderInactive = wxColour(0x00, 0x00, 0x00);
         }
         else
         {
-            m_bgActiveFrom = wxColour(0xE9, 0xE7, 0xEA);
+            m_textActive = wxColour(0x4B, 0x4B, 0x4B);
-            m_bgActiveTo = wxColour(0xCD, 0xCB, 0xCE);
+            m_textInactive = wxColour(0xB1, 0xB1, 0xB1);
-            m_borderActive = wxColour(0xBA, 0xB8, 0xBB);
-            m_borderInactive = wxColour(0xC3, 0xC3, 0xC3);
         }
-        SetBackgroundColour(bg); // inactive bg
     }
-    else
+    else // 10.10 Yosemite to 10.13:
     {
-        // 10.10 Yosemite to 10.13 :
+
         m_textActive = wxColour(0x40, 0x40, 0x40);
         m_textInactive = wxColour(0x4B, 0x4B, 0x4B);
-        m_bgActiveFrom = wxColour(0xE9, 0xE7, 0xEA);
-        m_bgActiveTo = wxColour(0xCD, 0xCB, 0xCE);
-        m_borderActive = wxColour(0xBA, 0xB8, 0xBB);
-        m_borderInactive = wxColour(0xC3, 0xC3, 0xC3);
-        SetBackgroundColour(wxColour(0xF4, 0xF4, 0xF4)); // inactive bg
     }
 }
 
@@ -165,10 +145,6 @@ void wxStatusBarMac::DoUpdateStatusText(int number)
 void wxStatusBarMac::OnPaint(wxPaintEvent& WXUNUSED(event))
 {
     wxPaintDC dc(this);
-    dc.Clear();
-
-    int w, h;
-    GetSize( &w, &h );
 
     // Notice that wxOSXGetKeyWindow (aka [NSApp keyWindow] used below is
     // subtly different from IsActive() (aka [NSWindow iskeyWindow]): the
@@ -188,22 +164,9 @@ void wxStatusBarMac::OnPaint(wxPaintEvent& WXUNUSED(event))
             break;
     }
 
-    if ( tlw == keyWindow )
+    // Don't paint any background, that's handled by the OS. Only draw text:
-    {
-        dc.GradientFillLinear(dc.GetSize(), m_bgActiveFrom, m_bgActiveTo, wxBOTTOM);
 
-        // Finder statusbar border color
+    dc.SetTextForeground(tlw == keyWindow ? m_textActive : m_textInactive);
-        dc.SetPen(wxPen(m_borderActive, 2, wxPENSTYLE_SOLID));
-        dc.SetTextForeground(m_textActive);
-    }
-    else
-    {
-        // Finder statusbar border color
-        dc.SetPen(wxPen(m_borderInactive, 2, wxPENSTYLE_SOLID));
-        dc.SetTextForeground(m_textInactive);
-    }
-
-    dc.DrawLine(0, 0, w, 0);
 
     if ( GetFont().IsOk() )
         dc.SetFont(GetFont());

src/osx/cocoa/nonownedwnd.mm

@@ -1288,6 +1288,12 @@ void wxNonOwnedWindowCocoaImpl::SetRepresentedFilename(const wxString& filename)
     [m_macWindow setRepresentedFilename:wxCFStringRef(filename).AsNSString()];
 }
 
+void wxNonOwnedWindowCocoaImpl::SetBottomBorderThickness(int thickness)
+{
+    [m_macWindow setAutorecalculatesContentBorderThickness:(thickness ? NO : YES) forEdge:NSMinYEdge];
+    [m_macWindow setContentBorderThickness:thickness forEdge:NSMinYEdge];
+}
+
 void wxNonOwnedWindowCocoaImpl::RestoreWindowLevel()
 {
     if ( [m_macWindow level] != m_macWindowLevel )