5 files changed, 21 insertions, 5 deletions
diff --git a/indra/llwindow/llwindowcallbacks.cpp b/indra/llwindow/llwindowcallbacks.cpp
index c160382c17..195f68e08b 100644
--- a/indra/llwindow/llwindowcallbacks.cpp
+++ b/indra/llwindow/llwindowcallbacks.cpp
@@ -194,6 +194,11 @@ bool LLWindowCallbacks::handleDPIChanged(LLWindow *window, F32 ui_scale_factor,
     return false;
 }
 
+bool LLWindowCallbacks::handleDisplayChanged()
+{
+    return false;
+}
+
 bool LLWindowCallbacks::handleWindowDidChangeScreen(LLWindow *window)
 {
     return false;
diff --git a/indra/llwindow/llwindowcallbacks.h b/indra/llwindow/llwindowcallbacks.h
index 63b585231f..d812f93524 100644
--- a/indra/llwindow/llwindowcallbacks.h
+++ b/indra/llwindow/llwindowcallbacks.h
@@ -69,6 +69,7 @@ public:
     virtual bool handleTimerEvent(LLWindow *window);
     virtual bool handleDeviceChange(LLWindow *window);
     virtual bool handleDPIChanged(LLWindow *window, F32 ui_scale_factor, S32 window_width, S32 window_height);
+    virtual bool handleDisplayChanged();
     virtual bool handleWindowDidChangeScreen(LLWindow *window);
 
     enum DragNDropAction {
diff --git a/indra/llwindow/llwindowwin32.cpp b/indra/llwindow/llwindowwin32.cpp
index 5defa662fa..832cf254d1 100644
--- a/indra/llwindow/llwindowwin32.cpp
+++ b/indra/llwindow/llwindowwin32.cpp
@@ -81,10 +81,6 @@ const S32   BITS_PER_PIXEL = 32;
 const S32   MAX_NUM_RESOLUTIONS = 32;
 const F32   ICON_FLASH_TIME = 0.5f;
 
-#ifndef WM_DPICHANGED
-#define WM_DPICHANGED 0x02E0
-#endif
-
 #ifndef USER_DEFAULT_SCREEN_DPI
 #define USER_DEFAULT_SCREEN_DPI 96 // Win7
 #endif
@@ -2969,6 +2965,11 @@ LRESULT CALLBACK LLWindowWin32::mainWindowProc(HWND h_wnd, UINT u_msg, WPARAM w_
             return 0;
         }
 
+        case WM_DISPLAYCHANGE:
+        {
+            WINDOW_IMP_POST(window_imp->mCallbacks->handleDisplayChanged());
+        }
+
         case WM_SETFOCUS:
         {
             LL_PROFILE_ZONE_NAMED_CATEGORY_WIN32("mwp - WM_SETFOCUS");
diff --git a/indra/newview/llviewerwindow.cpp b/indra/newview/llviewerwindow.cpp
index 8915e68298..5a7d507b74 100644
--- a/indra/newview/llviewerwindow.cpp
+++ b/indra/newview/llviewerwindow.cpp
@@ -1746,11 +1746,11 @@ bool LLViewerWindow::handleDeviceChange(LLWindow *window)
 
 bool LLViewerWindow::handleDPIChanged(LLWindow *window, F32 ui_scale_factor, S32 window_width, S32 window_height)
 {
+    LLFontGL::sResolutionGeneration++;
     if (ui_scale_factor >= MIN_UI_SCALE && ui_scale_factor <= MAX_UI_SCALE)
     {
         LLViewerWindow::reshape(window_width, window_height);
         mResDirty = true;
-        LLFontGL::sResolutionGeneration++;
         return true;
     }
     else
@@ -1760,6 +1760,12 @@ bool LLViewerWindow::handleDPIChanged(LLWindow *window, F32 ui_scale_factor, S32
     }
 }
 
+bool LLViewerWindow::handleDisplayChanged()
+{
+    LLFontGL::sResolutionGeneration++;
+    return false;
+}
+
 bool LLViewerWindow::handleWindowDidChangeScreen(LLWindow *window)
 {
     LLCoordScreen window_rect;
@@ -1928,6 +1934,7 @@ LLViewerWindow::LLViewerWindow(const Params& p)
     mDisplayScale.setVec(llmax(1.f / mWindow->getPixelAspectRatio(), 1.f), llmax(mWindow->getPixelAspectRatio(), 1.f));
     mDisplayScale *= ui_scale_factor;
     LLUI::setScaleFactor(mDisplayScale);
+    LLFontGL::sResolutionGeneration++;
 
     {
         LLCoordWindow size;
@@ -2495,6 +2502,7 @@ void LLViewerWindow::reshape(S32 width, S32 height)
 
         bool display_scale_changed = mDisplayScale != LLUI::getScaleFactor();
         LLUI::setScaleFactor(mDisplayScale);
+        LLFontGL::sResolutionGeneration++;
 
         // update our window rectangle
         mWindowRectScaled.mRight = mWindowRectScaled.mLeft + ll_round((F32)width / mDisplayScale.mV[VX]);
diff --git a/indra/newview/llviewerwindow.h b/indra/newview/llviewerwindow.h
index 1b995ea650..fbc2c58fbf 100644
--- a/indra/newview/llviewerwindow.h
+++ b/indra/newview/llviewerwindow.h
@@ -225,6 +225,7 @@ public:
     /*virtual*/ bool handleTimerEvent(LLWindow *window);
     /*virtual*/ bool handleDeviceChange(LLWindow *window);
     /*virtual*/ bool handleDPIChanged(LLWindow *window, F32 ui_scale_factor, S32 window_width, S32 window_height);
+    /*virtual*/ bool handleDisplayChanged();
     /*virtual*/ bool handleWindowDidChangeScreen(LLWindow *window);
 
     /*virtual*/ void handlePingWatchdog(LLWindow *window, const char * msg);