implement wxDC::GetContentScaleFactor() for GTK3

include/wx/gtk/dc.h

@@ -19,6 +19,7 @@ class wxGTKCairoDCImpl: public wxGCDCImpl
 public:
     wxGTKCairoDCImpl(wxDC* owner);
     wxGTKCairoDCImpl(wxDC* owner, int);
+    wxGTKCairoDCImpl(wxDC* owner, double scaleFactor);
     wxGTKCairoDCImpl(wxDC* owner, wxWindow* window);
 
     virtual void DoDrawBitmap(const wxBitmap& bitmap, int x, int y, bool useMask) wxOVERRIDE;
@@ -103,7 +104,7 @@ class WXDLLIMPEXP_CORE wxGTKCairoDC: public wxDC
 {
     typedef wxDC base_type;
 public:
-    wxGTKCairoDC(cairo_t* cr);
+    wxGTKCairoDC(cairo_t* cr, wxWindow* window);
 
     wxDECLARE_NO_COPY_CLASS(wxGTKCairoDC);
 };

src/gtk/dataview.cpp

@@ -2492,17 +2492,19 @@ wxDC *wxDataViewCustomRenderer::GetDC()
 {
     if (m_dc == NULL)
     {
+        wxDataViewCtrl* ctrl = NULL;
+        wxDataViewColumn* column = GetOwner();
+        if (column)
+            ctrl = column->GetOwner();
 #ifdef __WXGTK3__
         wxASSERT(m_renderParams);
         cairo_t* cr = m_renderParams->cr;
         wxASSERT(cr && cairo_status(cr) == 0);
-        m_dc = new wxGTKCairoDC(cr);
+        m_dc = new wxGTKCairoDC(cr, ctrl);
 #else
-        if (GetOwner() == NULL)
+        if (ctrl == NULL)
             return NULL;
-        if (GetOwner()->GetOwner() == NULL)
+        m_dc = new wxDataViewCtrlDC(ctrl);
-            return NULL;
-        m_dc = new wxDataViewCtrlDC( GetOwner()->GetOwner() );
 #endif
     }
 

src/gtk/dc.cpp

@@ -34,6 +34,14 @@ wxGTKCairoDCImpl::wxGTKCairoDCImpl(wxDC* owner, int)
     m_height = 0;
 }
 
+wxGTKCairoDCImpl::wxGTKCairoDCImpl(wxDC* owner, double scaleFactor)
+    : base_type(owner, 0)
+{
+    m_width = 0;
+    m_height = 0;
+    m_contentScaleFactor = scaleFactor;
+}
+
 wxGTKCairoDCImpl::wxGTKCairoDCImpl(wxDC* owner, wxWindow* window)
     : base_type(owner, 0)
 {
@@ -43,6 +51,7 @@ wxGTKCairoDCImpl::wxGTKCairoDCImpl(wxDC* owner, wxWindow* window)
     m_textBackgroundColour = window->GetBackgroundColour();
     m_width = 0;
     m_height = 0;
+    m_contentScaleFactor = window->GetContentScaleFactor();
 }
 
 void wxGTKCairoDCImpl::DoDrawBitmap(const wxBitmap& bitmap, int x, int y, bool useMask)
@@ -345,6 +354,7 @@ void wxMemoryDCImpl::Setup()
     {
         m_width = int(m_bitmap.GetScaledWidth());
         m_height = int(m_bitmap.GetScaledHeight());
+        m_contentScaleFactor = m_bitmap.GetScaleFactor();
         cairo_t* cr = m_bitmap.CairoCreate();
         gc = wxGraphicsContext::CreateFromNative(cr);
         gc->EnableOffset(true);
@@ -353,8 +363,8 @@ void wxMemoryDCImpl::Setup()
 }
 //-----------------------------------------------------------------------------
 
-wxGTKCairoDC::wxGTKCairoDC(cairo_t* cr)
+wxGTKCairoDC::wxGTKCairoDC(cairo_t* cr, wxWindow* window)
-    : base_type(new wxGTKCairoDCImpl(this, 0))
+    : base_type(new wxGTKCairoDCImpl(this, window->GetContentScaleFactor()))
 {
     cairo_reference(cr);
     wxGraphicsContext* gc = wxGraphicsContext::CreateFromNative(cr);

src/gtk/minifram.cpp

@@ -56,7 +56,7 @@ static gboolean expose_event(GtkWidget* widget, GdkEventExpose* gdk_event, wxMin
     gtk_render_frame(sc, cr, 0, 0, win->m_width, win->m_height);
     gtk_style_context_restore(sc);
 
-    wxGTKCairoDC dc(cr);
+    wxGTKCairoDC dc(cr, win);
 #else
     if (gdk_event->count > 0 ||
         gdk_event->window != gtk_widget_get_window(widget))

src/gtk/window.cpp

@@ -4222,7 +4222,7 @@ void wxWindowGTK::GTKSendPaintEvents(const GdkRegion* region)
         case wxBG_STYLE_ERASE:
             {
 #ifdef __WXGTK3__
-                wxGTKCairoDC dc(cr);
+                wxGTKCairoDC dc(cr, static_cast<wxWindow*>(this));
 #else
                 wxWindowDC dc( (wxWindow*)this );
                 dc.SetDeviceClippingRegion( m_updateRegion );