include/wx/msw/private/metrics.h

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // Name:        wx/msw/private/metrics.h
   3 // Purpose:     various helper functions to retrieve system metrics
   4 // Author:      Vadim Zeitlin
   5 // Created:     2008-09-05
   6 // Copyright:   (c) 2008 Vadim Zeitlin <vadim@wxwidgets.org>
   7 // Licence:     wxWindows licence
   8 ///////////////////////////////////////////////////////////////////////////////
   9
  10 #ifndef _WX_MSW_PRIVATE_METRICS_H_
  11 #define _WX_MSW_PRIVATE_METRICS_H_
  12
  13 namespace wxMSWImpl
  14 {
  15
  16 // return NONCLIENTMETRICS as retrieved by SystemParametersInfo()
  17 //
  18 // currently this is not cached as the values may change when system settings
  19 // do and we don't react to this to invalidate the cache but it could be done
  20 // in the future
  21 //
  22 // MT-safety: this function is only meant to be called from the main thread
  23 inline const NONCLIENTMETRICS& GetNonClientMetrics()
  24 {
  25     static WinStruct<NONCLIENTMETRICS> nm;
  26     if ( !::SystemParametersInfo(SPI_GETNONCLIENTMETRICS, 0, &nm, 0) )
  27     {
  28 #if WINVER >= 0x0600
  29         // a new field has been added to NONCLIENTMETRICS under Vista, so
  30         // the call to SystemParametersInfo() fails if we use the struct
  31         // size incorporating this new value on an older system -- retry
  32         // without it
  33         nm.cbSize -= sizeof(int);
  34         if ( !::SystemParametersInfo(SPI_GETNONCLIENTMETRICS, 0, &nm, 0) )
  35 #endif // WINVER >= 0x0600
  36         {
  37             // maybe we should initialize the struct with some defaults?
  38             wxLogLastError(wxT("SystemParametersInfo(SPI_GETNONCLIENTMETRICS)"));
  39         }
  40     }
  41
  42     return nm;
  43 }
  44
  45 } // namespace wxMSWImpl
  46
  47 #endif // _WX_MSW_PRIVATE_METRICS_H_
  48