QWindowsTheme::themeHint(): Handle special value of SPI_GETWHEELSCROL…

…LLINES When the mouse wheel step is set to "Scroll one screen", querying SPI_GETWHEELSCROLLLINES returns the special value unsigned(-1). Return the default instead of converting it to int in that case since Qt does not implement it. Task-number: QTBUG-52384 Change-Id: I793e5c09103fe0c7c4a378aba97e9f63ae1c2f35 Reviewed-by: Giuseppe D'Angelo <[email protected]> Reviewed-by: Oliver Wolff <[email protected]>
boris-fx · Jul 26, 2016 · 8ea6e8d · 8ea6e8d
1 parent 1fcea11
commit 8ea6e8d
Showing 1 changed file with 7 additions and 2 deletions.
diff --git a/src/plugins/platforms/windows/qwindowstheme.cpp b/src/plugins/platforms/windows/qwindowstheme.cpp
@@ -401,8 +401,13 @@ QVariant QWindowsTheme::themeHint(ThemeHint hint) const
         return QVariant(booleanSystemParametersInfo(SPI_GETSNAPTODEFBUTTON, false));
     case ContextMenuOnMouseRelease:
         return QVariant(true);
-    case WheelScrollLines:
-        return QVariant(int(dWordSystemParametersInfo(SPI_GETWHEELSCROLLLINES, 3)));
+    case WheelScrollLines: {
+        int result = 3;
+        const DWORD scrollLines = dWordSystemParametersInfo(SPI_GETWHEELSCROLLLINES, DWORD(result));
+        if (scrollLines != DWORD(-1)) // Special value meaning "scroll one screen", unimplemented in Qt.
+            result = int(scrollLines);
+        return QVariant(result);
+    }
     default:
         break;
     }