int logPPIScreenX = ::GetDeviceCaps(dc, LOGPIXELSX);
int logPPIScreenY = ::GetDeviceCaps(dc, LOGPIXELSY);
m_previewPrintout->SetPPIScreen(logPPIScreenX, logPPIScreenY);
int logPPIScreenX = ::GetDeviceCaps(dc, LOGPIXELSX);
int logPPIScreenY = ::GetDeviceCaps(dc, LOGPIXELSY);
m_previewPrintout->SetPPIScreen(logPPIScreenX, logPPIScreenY);