src/dfb/dcscreen.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        src/dfb/dcscreen.cpp
   3 // Purpose:     wxScreenDC implementation
   4 // Author:      Vaclav Slavik
   5 // Created:     2006-08-16
   6 // RCS-ID:      $Id$
   7 // Copyright:   (c) 2006 REA Elektronik GmbH
   8 // Licence:     wxWindows licence
   9 /////////////////////////////////////////////////////////////////////////////
  10
  11 // ===========================================================================
  12 // declarations
  13 // ===========================================================================
  14
  15 // ---------------------------------------------------------------------------
  16 // headers
  17 // ---------------------------------------------------------------------------
  18
  19 // For compilers that support precompilation, includes "wx.h".
  20 #include "wx/wxprec.h"
  21
  22 #include "wx/dcscreen.h"
  23 #include "wx/dfb/dcscreen.h"
  24 #include "wx/dfb/private.h"
  25
  26 // ===========================================================================
  27 // implementation
  28 // ===========================================================================
  29
  30 //-----------------------------------------------------------------------------
  31 // wxScreenDC
  32 //-----------------------------------------------------------------------------
  33
  34 // FIXME: Currently, wxScreenDC doesn't work at all in non-exclusive mode
  35 //        (DFSCL_NORMAL). In this mode, requesting primary surface results
  36 //        in one of the following actions, depending on directfbrc
  37 //        configuration:
  38 //
  39 //        (1) if force-desktop, a surface is created and used as *background*
  40 //            for the windows managed by DFB WM
  41 //
  42 //        (2) otherwise, a dummy surface of the right size and format is
  43 //            created, but isn't shown on the screen
  44 //
  45 //        (3) furthermore, if autoflip-window option is not used and primary
  46 //            surface is requested as single-buffered (which is needed to
  47 //            implement wxScreenDC semantics), a warning is issued in addition
  48 //            to 2); if autoflip-window is used, then a helper thread is
  49 //            created and does periodic flipping, which is even worse
  50 //
  51 //        2) and 3) are obviously unsatisfactory. 1) isn't suitable either,
  52 //        because wxScreenDC has to render *on top* of windows.
  53 //
  54 //        In conclusion, wxScreenDC as currently implemented is only usable
  55 //        for measuring things (e.g. font sizes). For this task, however, it
  56 //        is quite expensive to create in DFSCL_NORMAL mode, because it
  57 //        involves creation of a new surface as big as the screen.
  58 //
  59 //        The surface, as obtained from GetPrimarySurface(), is double-buffered
  60 //        for the sole purpose of silencing the warning from 3) above.
  61
  62 IMPLEMENT_ABSTRACT_CLASS(wxScreenDCImpl, wxDFBDCImpl)
  63
  64 wxScreenDCImpl::wxScreenDCImpl(wxScreenDC *owner)
  65               : wxDFBDCImpl(owner)
  66 {
  67     DFBInit(wxIDirectFB::Get()->GetPrimarySurface());
  68 }