X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/c4a34cf8c5b5261f8726fdbfe0b2464dd35df268..9e1fc0e42822fdf1159582f1b73cde0c7d15bc92:/include/wx/dcbuffer.h?ds=sidebyside

diff --git a/include/wx/dcbuffer.h b/include/wx/dcbuffer.h
index 6e26da6f97..ef5383bbdf 100644
--- a/include/wx/dcbuffer.h
+++ b/include/wx/dcbuffer.h
@@ -50,10 +50,9 @@ public:
 
     // Construct a wxBufferedDC using a user supplied buffer.
     wxBufferedDC(wxDC *dc,
-                 const wxBitmap& buffer = wxNullBitmap,
+                 wxBitmap& buffer = wxNullBitmap,
                  int style = wxBUFFER_CLIENT_AREA)
-        : m_dc(NULL),
-          m_buffer(NULL)
+        : m_dc(NULL), m_buffer(NULL)
     {
         Init(dc, buffer, style);
     }
@@ -62,9 +61,7 @@ public:
     // (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(NULL),
-          m_buffer(NULL)
-
+        : m_dc(NULL), m_buffer(NULL)
     {
         Init(dc, area, style);
     }
@@ -78,7 +75,7 @@ public:
 
     // These reimplement the actions of the ctors for two stage creation
     void Init(wxDC *dc,
-              const wxBitmap& buffer = wxNullBitmap,
+              wxBitmap& buffer = wxNullBitmap,
               int style = wxBUFFER_CLIENT_AREA)
     {
         InitCommon(dc, style);
@@ -103,7 +100,8 @@ public:
     // blitting to) is destroyed.
     void UnMask()
     {
-        wxCHECK_RET( m_dc, _T("No underlying DC in wxBufferedDC") );
+        wxCHECK_RET( m_dc, _T("no underlying wxDC?") );
+        wxASSERT_MSG( m_buffer && m_buffer->IsOk(), _T("invalid backing store") );
 
         wxCoord x = 0,
                 y = 0;
@@ -124,14 +122,14 @@ private:
     // common part of Init()s
     void InitCommon(wxDC *dc, int style)
     {
-        wxASSERT_MSG( !m_dc && !m_buffer, _T("wxBufferedDC already initialised") );
-        wxCHECK_RET( dc, _T("can't associate NULL DC with wxBufferedDC") );
+        wxASSERT_MSG( !m_dc, _T("wxBufferedDC already initialised") );
 
         m_dc = dc;
         m_style = style;
 
         // inherit the same layout direction as the original DC
-        SetLayoutDirection(dc->GetLayoutDirection());
+        if (dc && dc->IsOk())
+            SetLayoutDirection(dc->GetLayoutDirection());
     }
 
     // check that the bitmap is valid and use it
@@ -144,8 +142,8 @@ 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;
@@ -165,14 +163,14 @@ class WXDLLEXPORT wxBufferedPaintDC : public wxBufferedDC
 {
 public:
     // If no bitmap is supplied by the user, a temporary one will be created.
-    wxBufferedPaintDC(wxWindow *window, const wxBitmap& buffer, int style = wxBUFFER_CLIENT_AREA)
+    wxBufferedPaintDC(wxWindow *window, wxBitmap& buffer, int style = wxBUFFER_CLIENT_AREA)
         : m_paintdc(window)
     {
         // If we're buffering the virtual window, scale the paint DC as well
         if (style & wxBUFFER_VIRTUAL_AREA)
             window->PrepareDC( m_paintdc );
 
-        if( buffer != wxNullBitmap )
+        if( buffer.IsOk() )
             Init(&m_paintdc, buffer, style);
         else
             Init(&m_paintdc, window->GetClientSize(), style);