text: /////////////////////////////////////////////////////////////////////////////
  // Name:        src/dfb/overlay.cpp
  // Purpose:     wxOverlay implementation for wxDFB
  // Author:      Vaclav Slavik
  // Created:     2006-10-20
  // Copyright:   (c) wxWidgets team
  // Licence:     wxWindows licence
  /////////////////////////////////////////////////////////////////////////////
  
  // ============================================================================
  // declarations
  // ============================================================================
  
  // ----------------------------------------------------------------------------
  // headers
  // ----------------------------------------------------------------------------
  
  // For compilers that support precompilation, includes "wx.h".
  #include "wx/wxprec.h"
  
  #ifdef __BORLANDC__
      #pragma hdrstop
  #endif
  
  #ifndef WX_PRECOMP
      #include "wx/window.h"
      #include "wx/dcclient.h"
  #endif
  
  #include "wx/private/overlay.h"
  #include "wx/dfb/dcclient.h"
  #include "wx/dfb/private.h"
  
  // ============================================================================
  // implementation
  // ============================================================================
  
  // ----------------------------------------------------------------------------
  // wxOverlay
  // ----------------------------------------------------------------------------
  
  wxOverlayImpl::wxOverlayImpl()
  {
      m_window = NULL;
      m_isEmpty = true;
  }
  
  wxOverlayImpl::~wxOverlayImpl()
  {
      Reset();
  }
  
  bool wxOverlayImpl::IsOk()
  {
      return m_window != NULL;
  }
  
  void wxOverlayImpl::Init(wxDC *dc, int x, int y, int width, int height)
  {
      wxCHECK_RET( dc, "NULL dc pointer" );
      wxASSERT_MSG( !IsOk() , _("You cannot Init an overlay twice") );
  
      wxDFBDCImpl * const dcimpl = wxDynamicCast(dc->GetImpl(), wxDFBDCImpl);
      wxCHECK_RET( dcimpl, "must have a DFB wxDC" );
  
      m_window = dc->GetWindow();
  
      m_rect = wxRect(x, y, width, height);
      if ( wxDynamicCast(dc, wxClientDC) )
          m_rect.Offset(m_window->GetClientAreaOrigin());
  
      // FIXME: create surface with transparency or key color (?)
      m_surface = dcimpl->GetDirectFBSurface()->CreateCompatible
                  (
                     m_rect.GetSize(),
                     wxIDirectFBSurface::CreateCompatible_NoBackBuffer
                  );
  
      m_window->AddOverlay(this);
  }
  
  void wxOverlayImpl::BeginDrawing(wxDC *dc)
  {
      wxCHECK_RET( dc, "NULL dc pointer" );
  
      wxWindowDCImpl * const
          dcimpl = static_cast<wxWindowDCImpl *>(dc->GetImpl());
  
      wxPoint origin(m_rect.GetPosition());
      if ( wxDynamicCast(dc, wxClientDC) )
          origin -= m_window->GetClientAreaOrigin();
  
      // drawing on overlay "hijacks" existing wxWindowDC rather then using
      // another DC, so we have to change the DC to draw on the overlay's surface.
      // Setting m_shouldFlip is done to avoid flipping and drawing of overlays
      // in ~wxWindowDC (we do it EndDrawing).
      dcimpl->DFBInit(m_surface);
      dcimpl->m_shouldFlip = false;
      dc->SetDeviceOrigin(-origin.x, -origin.y);
  
      m_isEmpty = false;
  }
  
  void wxOverlayImpl::EndDrawing(wxDC *WXUNUSED(dc))
  {
      m_window->RefreshWindowRect(m_rect);
  }
  
  void wxOverlayImpl::Clear(wxDC *WXUNUSED(dc))
  {
      wxASSERT_MSG( IsOk(),
                    "You cannot Clear an overlay that is not initialized" );
  
      m_isEmpty = true;
  }
  
  void wxOverlayImpl::Reset()
  {
      if ( m_window )
      {
          m_window->RemoveOverlay(this);
          m_window = NULL;
          m_surface.Reset();
      }
  }
  