SL-10891 Reset UI scale factor on first run if OS's display scaling is not 100%

doc/contributions.txt

@@ -222,6 +222,7 @@ Ansariel Hiller
 	MAINT-8085
 	MAINT-8723
 	SL-10385
+	SL-10891
 Aralara Rajal
 Arare Chantilly
 	CHUIBUG-191

indra/newview/app_settings/settings.xml

@@ -16310,6 +16310,19 @@
       <key>Value</key>
       <integer>0</integer>
     </map>
+    <key>ResetUIScaleOnFirstRun</key>
+    <map>
+      <key>Comment</key>
+      <string>Resets the UI scale factor on first run due to changed display scaling behavior</string>
+      <key>Persist</key>
+      <integer>1</integer>
+      <key>Type</key>
+      <string>Boolean</string>
+      <key>Value</key>
+      <integer>1</integer>
+      <key>Backup</key>
+      <integer>0</integer>        
+    </map>
 </map>
 </llsd>
 

indra/newview/llviewerwindow.cpp

@@ -1763,6 +1763,16 @@ LLViewerWindow::LLViewerWindow(const Params& p)
 	LLCoordScreen scr;
     mWindow->getSize(&scr);
 
+    // Reset UI scale factor on first run if OS's display scaling is not 100%
+    if (gSavedSettings.getBOOL("FSResetUIScaleOnFirstRun"))
+    {
+        if (mWindow->getSystemUISize() != 1.f)
+        {
+            gSavedSettings.setF32("UIScaleFactor", 1.f);
+        }
+        gSavedSettings.setBOOL("ResetUIScaleOnFirstRun", FALSE);
+    }
+
 	// Get the real window rect the window was created with (since there are various OS-dependent reasons why
 	// the size of a window or fullscreen context may have been adjusted slightly...)
 	F32 ui_scale_factor = llclamp(gSavedSettings.getF32("UIScaleFactor"), MIN_UI_SCALE, MAX_UI_SCALE) * mWindow->getSystemUISize();