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 // RCS-ID:      $Id$
   7 // Copyright:   (c) 2008 Vadim Zeitlin <vadim@wxwidgets.org>
   8 // Licence:     wxWindows licence
   9 ///////////////////////////////////////////////////////////////////////////////
  10
  11 #ifndef _WX_MSW_PRIVATE_METRICS_H_
  12 #define _WX_MSW_PRIVATE_METRICS_H_
  13
  14 namespace wxMSWImpl
  15 {
  16
  17 // return NONCLIENTMETRICS as retrieved by SystemParametersInfo()
  18 //
  19 // currently this is not cached as the values may change when system settings
  20 // do and we don't react to this to invalidate the cache but it could be done
  21 // in the future
  22 //
  23 // MT-safety: this function is only meant to be called from the main thread
  24 inline const NONCLIENTMETRICS& GetNonClientMetrics()
  25 {
  26     static WinStruct<NONCLIENTMETRICS> nm;
  27     if ( !::SystemParametersInfo(SPI_GETNONCLIENTMETRICS, 0, &nm, 0) )
  28     {
  29 #if WINVER >= 0x0600
  30         // a new field has been added to NONCLIENTMETRICS under Vista, so
  31         // the call to SystemParametersInfo() fails if we use the struct
  32         // size incorporating this new value on an older system -- retry
  33         // without it
  34         nm.cbSize -= sizeof(int);
  35         if ( !::SystemParametersInfo(SPI_GETNONCLIENTMETRICS, 0, &nm, 0) )
  36 #endif // WINVER >= 0x0600
  37         {
  38             // maybe we should initialize the struct with some defaults?
  39             wxLogLastError(_T("SystemParametersInfo(SPI_GETNONCLIENTMETRICS)"));
  40         }
  41     }
  42
  43     return nm;
  44 }
  45
  46 } // namespace wxMSWImpl
  47
  48 #endif // _WX_MSW_PRIVATE_METRICS_H_
  49