defer dc screen grab until blit

include/wx/qt/dc.h

@@ -111,6 +111,8 @@ public:
     virtual void* GetHandle() const { return (void*) m_qtPainter; }
 
 protected:
+    virtual QImage *GetQImage() { return m_qtImage; }
+    
     QPainter *m_qtPainter;
     QImage *m_qtImage;
 

include/wx/qt/dcclient.h

@@ -20,9 +20,6 @@ public:
 
 protected:
     wxWindow *m_window;
-
-private:
-
 };
 
 

include/wx/qt/dcmemory.h

@@ -24,8 +24,6 @@ public:
     virtual const wxBitmap& GetSelectedBitmap() const;
     virtual wxBitmap& GetSelectedBitmap();
 
-protected:
-
 private:
     wxBitmap m_selected;
 };

include/wx/qt/dcscreen.h

@@ -17,9 +17,11 @@ public:
 
     ~wxScreenDCImpl();
 
+protected:
     virtual void DoGetSize(int *width, int *height) const wxOVERRIDE;
+    virtual bool DoGetPixel(wxCoord x, wxCoord y, wxColour *col) const;
 
-private:
+    QImage *GetQImage();
 
     wxDECLARE_ABSTRACT_CLASS(wxScreenDCImpl);
 };

src/qt/dc.cpp

@@ -745,7 +745,7 @@ bool wxQtDCImpl::DoBlit(wxCoord xdest, wxCoord ydest,
 {
     wxQtDCImpl *implSource = (wxQtDCImpl*)source->GetImpl();
     
-    QImage *qtSource = implSource->m_qtImage;
+    QImage *qtSource = implSource->GetQImage();
     
     // Not a CHECK on purpose
     if ( !qtSource )

src/qt/dcclient.cpp

@@ -31,6 +31,7 @@ wxWindowDCImpl::wxWindowDCImpl( wxDC *owner )
     : wxQtDCImpl( owner )
 {
     m_window = NULL;
+    m_qtImage = NULL;
     m_ok = false;
     m_qtPainter = new QPainter();
 }
@@ -39,6 +40,7 @@ wxWindowDCImpl::wxWindowDCImpl( wxDC *owner, wxWindow *win )
     : wxQtDCImpl( owner )
 {
     m_window = win;
+    m_qtImage = NULL;
     m_qtPainter = m_window->QtGetPainter();
     // if we're not inside a Paint event, painter will invalid
     m_ok = m_qtPainter != NULL;

src/qt/dcmemory.cpp

@@ -35,6 +35,7 @@ wxMemoryDCImpl::wxMemoryDCImpl( wxMemoryDC *owner, wxDC *WXUNUSED(dc) )
 {
     m_qtImage = NULL;
     m_ok = false;
+    m_qtPainter = new QPainter();
 }
 
 wxMemoryDCImpl::~wxMemoryDCImpl()

src/qt/dcscreen.cpp

@@ -21,7 +21,7 @@ wxIMPLEMENT_ABSTRACT_CLASS(wxScreenDCImpl, wxWindowDCImpl);
 wxScreenDCImpl::wxScreenDCImpl( wxScreenDC *owner )
     : wxWindowDCImpl( owner )
 {
-    m_qtImage = new QImage(QApplication::primaryScreen()->grabWindow(QApplication::desktop()->winId()).toImage());
+    m_qtImage = NULL;
 }
 
 wxScreenDCImpl::~wxScreenDCImpl( )
@@ -33,3 +33,20 @@ void wxScreenDCImpl::DoGetSize(int *width, int *height) const
 {
     wxDisplaySize(width, height);
 }
+
+bool wxScreenDCImpl::DoGetPixel(wxCoord x, wxCoord y, wxColour *col) const
+{
+//    const_cast<wxScreenDCImpl*>(this)->GetQImage();
+//    return wxQtDCImpl::DoGetPixel(x, y, col);
+    x = y = 0;
+    col = 0;
+    return false;
+}
+
+// defered allocation for blit
+QImage *wxScreenDCImpl::GetQImage()
+{
+    if(!m_qtImage)
+        m_qtImage = new QImage(QApplication::primaryScreen()->grabWindow(QApplication::desktop()->winId()).toImage());
+    return m_qtImage;
+}