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