Fixed initialisation order warning

[wxWidgets.git] / include / wx / dcbuffer.h

diff --git a/include/wx/dcbuffer.h b/include/wx/dcbuffer.h
index 784d88766e49b0fba02092d26e07cc74f20d4f63..1b12cc6f055f47b01df3bb03cd50c75a2a850fcd 100644 (file)
--- a/include/wx/dcbuffer.h
+++ b/include/wx/dcbuffer.h
@@ -41,62 +41,53 @@ class WXDLLEXPORT wxBufferedDC : public wxMemoryDC
 {
 public:
     // Default ctor, must subsequently call Init for two stage construction.
-    wxBufferedDC() : m_dc( 0 ), m_buffer(NULL), m_style(0)
+    wxBufferedDC()
+        : m_dc(NULL),
+          m_style(0)
     {
     }
 
     // Construct a wxBufferedDC using a user supplied buffer.
     wxBufferedDC(wxDC *dc,
-                 const wxBitmap &buffer = wxNullBitmap,
+                 const wxBitmap& buffer = wxNullBitmap,
                  int style = wxBUFFER_CLIENT_AREA)
-        : m_dc( dc ),
-          m_buffer( &buffer ),
-          m_style(style)
+        : m_dc(NULL)
     {
-        UseBuffer();
+        Init(dc, buffer, style);
     }
 
     // Construct a wxBufferedDC with an internal buffer of 'area'
     // (where area is usually something like the size of the window
     // being buffered)
-    wxBufferedDC(wxDC *dc, const wxSize &area, int style = wxBUFFER_CLIENT_AREA)
-        : m_dc( dc ),
-          m_buffer(NULL),
-          m_style(style)
-
+    wxBufferedDC(wxDC *dc, const wxSize& area, int style = wxBUFFER_CLIENT_AREA)
+        : m_dc(NULL)
     {
-        UseBuffer(area.x, area.y);
+        Init(dc, area, style);
     }
 
-    // default copy ctor ok.
-
     // The usually desired  action in the dtor is to blit the buffer.
     virtual ~wxBufferedDC()
     {
-        if ( m_dc ) UnMask();
+        if ( m_dc )
+            UnMask();
     }
 
-    // These reimplement the actions of the ctors for two stage creation, but
-    // are not used by the ctors themselves to save a few cpu cycles.
+    // These reimplement the actions of the ctors for two stage creation
     void Init(wxDC *dc,
-              const wxBitmap &buffer=wxNullBitmap,
+              const wxBitmap& buffer = wxNullBitmap,
               int style = wxBUFFER_CLIENT_AREA)
     {
-        wxASSERT_MSG( m_dc == 0 && m_buffer == NULL,
-                      _T("wxBufferedDC already initialised") );
-        m_dc = dc;
-        m_buffer = &buffer;
-        m_style = style;
+        InitCommon(dc, style);
+
+        m_buffer = buffer;
+
         UseBuffer();
     }
 
     void Init(wxDC *dc, const wxSize &area, int style = wxBUFFER_CLIENT_AREA)
     {
-        wxASSERT_MSG( m_dc == 0 && m_buffer == NULL,
-                      _T("wxBufferedDC already initialised") );
-        m_dc = dc;
-        m_buffer = NULL;
-        m_style = style;
+        InitCommon(dc, style);
+
         UseBuffer(area.x, area.y);
     }
 
@@ -108,17 +99,17 @@ public:
     // blitting to) is destroyed.
     void UnMask()
     {
-        wxASSERT_MSG( m_dc != 0,
-                      _T("No underlying DC associated with wxBufferedDC (anymore)") );
+        wxCHECK_RET( m_dc, _T("no underlying wxDC?") );
+        wxASSERT_MSG( m_buffer.IsOk(), _T("invalid backing store") );
 
-        wxCoord x=0, y=0;
+        wxCoord x = 0,
+                y = 0;
 
-        if (m_style & wxBUFFER_CLIENT_AREA)
+        if ( m_style & wxBUFFER_CLIENT_AREA )
             GetDeviceOrigin(&x, &y);
 
-        m_dc->Blit( 0, 0,
-                    m_buffer->GetWidth(), m_buffer->GetHeight(), this,
-                    -x, -y );
+        m_dc->Blit(0, 0, m_buffer.GetWidth(), m_buffer.GetHeight(),
+                   this, -x, -y );
         m_dc = NULL;
     }
 
@@ -127,6 +118,19 @@ public:
     int GetStyle() const { return m_style; }
 
 private:
+    // common part of Init()s
+    void InitCommon(wxDC *dc, int style)
+    {
+        wxASSERT_MSG( !m_dc, _T("wxBufferedDC already initialised") );
+
+        m_dc = dc;
+        m_style = style;
+
+        // inherit the same layout direction as the original DC
+        if (dc && dc->IsOk())
+            SetLayoutDirection(dc->GetLayoutDirection());
+    }
+
     // check that the bitmap is valid and use it
     void UseBuffer(wxCoord w = -1, wxCoord h = -1);
 
@@ -137,8 +141,8 @@ private:
     //     could probably be a reference.
     wxDC *m_dc;
 
-    // the buffer (selected in this DC)
-    const wxBitmap *m_buffer;
+    // the buffer (selected in this DC), initially invalid
+    wxBitmap m_buffer;
 
     // the buffering style
     int m_style;
@@ -258,6 +262,5 @@ inline wxDC* wxAutoBufferedPaintDCFactory(wxWindow* window)
     else
         return new wxBufferedPaintDC(window);
 }
-            
 
 #endif  // _WX_DCBUFFER_H_