Merge branch 'msw-display-refresh'

Fixes for display information refreshing under MSW.

See https://github.com/wxWidgets/wxWidgets/pull/1282

samples/display/display.cpp

@@ -81,6 +81,9 @@ public:
     void OnLeftClick(wxMouseEvent& event);
 
 private:
+    // Fill m_book with the information about all the displays.
+    void PopuplateWithDisplayInfo();
+
 #if wxUSE_DISPLAY
     // convert video mode to textual description
     wxString VideoModeToText(const wxVideoMode& mode);
@@ -233,6 +236,11 @@ MyFrame::MyFrame(const wxString& title, const wxPoint& pos, const wxSize& size,
 
     // create child controls
     m_book = new wxBookCtrl(this, wxID_ANY);
+    PopuplateWithDisplayInfo();
+}
+
+void MyFrame::PopuplateWithDisplayInfo()
+{
     const size_t countDpy = wxDisplay::GetCount();
     for ( size_t nDpy = 0; nDpy < countDpy; nDpy++ )
     {
@@ -426,16 +434,8 @@ void MyFrame::OnLeftClick(wxMouseEvent& event)
 
 void MyFrame::OnDisplayChanged(wxDisplayChangedEvent& event)
 {
-    // update the current mode text
-    for ( size_t n = 0; n < m_book->GetPageCount(); n++ )
-    {
-        wxStaticText *label = wxDynamicCast(m_book->GetPage(n)->
-                                                FindWindow(Display_CurrentMode),
-                                            wxStaticText);
-        if ( label )
-            label->SetLabel(VideoModeToText(wxDisplay(n).GetCurrentMode()));
-    }
-
+    m_book->DeleteAllPages();
+    PopuplateWithDisplayInfo();
 
     wxLogStatus(this, "Display resolution was changed.");
 

src/msw/display.cpp

@@ -198,10 +198,6 @@ public:
         DoRefreshMonitors();
     }
 
-    // Called when we receive WM_SETTINGCHANGE to refresh the list of monitor
-    // handles.
-    static void RefreshMonitors() { ms_factory->InvalidateCache(); }
-
     // Declare the second argument as int to avoid problems with older SDKs not
     // declaring MONITOR_DPI_TYPE enum.
     typedef HRESULT (WINAPI *GetDpiForMonitor_t)(HMONITOR, int, UINT*, UINT*);
@@ -221,15 +217,9 @@ private:
     // return wxNOT_FOUND if not found
     int FindDisplayFromHMONITOR(HMONITOR hmon) const;
 
-    // Update m_displays array, used by RefreshMonitors().
+    // Update m_displays array, used initially and by InvalidateCache().
     void DoRefreshMonitors();
 
-
-    // The unique factory being used (as we don't have direct access to the
-    // global factory pointer in the common code so we just duplicate this
-    // variable (also making it of correct type for us) here).
-    static wxDisplayFactoryMSW* ms_factory;
-
     // The pointer to GetDpiForMonitorPtr(), retrieved on demand, and the
     // related data, including the DLL containing the function that we must
     // keep loaded.
@@ -285,7 +275,6 @@ private:
     wxDECLARE_NO_COPY_CLASS(wxDisplayFactoryMSW);
 };
 
-wxDisplayFactoryMSW* wxDisplayFactoryMSW::ms_factory = NULL;
 wxDisplayFactoryMSW::GetDpiForMonitorData
     wxDisplayFactoryMSW::ms_getDpiForMonitorData;
 
@@ -535,7 +524,8 @@ bool wxDisplayMSW::ChangeMode(const wxVideoMode& mode)
 LRESULT APIENTRY
 wxDisplayWndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
 {
-    if ( msg == WM_SETTINGCHANGE || msg == WM_DISPLAYCHANGE )
+    if ( (msg == WM_SETTINGCHANGE && wParam == SPI_SETWORKAREA) ||
+            msg == WM_DISPLAYCHANGE )
     {
         wxDisplay::InvalidateCache();
 
@@ -547,12 +537,6 @@ wxDisplayWndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
 
 wxDisplayFactoryMSW::wxDisplayFactoryMSW()
 {
-    // This is not supposed to happen with the current code, the factory is
-    // implicitly a singleton.
-    wxASSERT_MSG( !ms_factory, wxS("Using more than one factory?") );
-
-    ms_factory = this;
-
     m_hiddenHwnd = NULL;
     m_hiddenClass = NULL;
 
@@ -592,8 +576,6 @@ wxDisplayFactoryMSW::~wxDisplayFactoryMSW()
         ms_getDpiForMonitorData.UnloadIfNecessary();
         ms_getDpiForMonitorData.m_initialized = false;
     }
-
-    ms_factory = NULL;
 }
 
 /* static */
@@ -613,10 +595,10 @@ void wxDisplayFactoryMSW::DoRefreshMonitors()
 {
     m_displays.clear();
 
-    // We need to pass a valid HDC here in order to get valid hdcMonitor in our
-    // callback.
-    ScreenHDC dc;
-    if ( !::EnumDisplayMonitors(dc, NULL, MultimonEnumProc, (LPARAM)this) )
+    // Note that we pass NULL as first parameter here because using screen HDC
+    // doesn't work reliably: notably, it doesn't enumerate any displays if
+    // this code is executed while a UAC prompt is shown or during log-off.
+    if ( !::EnumDisplayMonitors(NULL, NULL, MultimonEnumProc, (LPARAM)this) )
     {
         wxLogLastError(wxT("EnumDisplayMonitors"));
     }
@@ -626,13 +608,24 @@ void wxDisplayFactoryMSW::DoRefreshMonitors()
 BOOL CALLBACK
 wxDisplayFactoryMSW::MultimonEnumProc(
     HMONITOR hMonitor,              // handle to display monitor
-    HDC hdcMonitor,                 // handle to monitor-appropriate device context
+    HDC /* hdcMonitor */,           // handle to monitor-appropriate device context:
+                                    // not set due to our use of EnumDisplayMonitors(NULL, ...)
     LPRECT WXUNUSED(lprcMonitor),   // pointer to monitor intersection rectangle
     LPARAM dwData)                  // data passed from EnumDisplayMonitors (this)
 {
     wxDisplayFactoryMSW *const self = (wxDisplayFactoryMSW *)dwData;
 
-    self->m_displays.push_back(wxDisplayInfo(hMonitor, wxGetHDCDepth(hdcMonitor)));
+    WinStruct<MONITORINFOEX> monInfo;
+    if ( !::GetMonitorInfo(hMonitor, &monInfo) )
+    {
+        wxLogLastError(wxT("GetMonitorInfo"));
+    }
+
+    HDC hdcMonitor = ::CreateDC(NULL, monInfo.szDevice, NULL, NULL);
+    const int hdcDepth = wxGetHDCDepth(hdcMonitor);
+    ::DeleteDC(hdcMonitor);
+
+    self->m_displays.push_back(wxDisplayInfo(hMonitor, hdcDepth));
 
     // continue the enumeration
     return TRUE;