[Qt4 demo] do not crash when changing the zoom with no document

1 files changed, 3 insertions, 0 deletions

diff --git a/qt4/demos/pageview.cpp b/qt4/demos/pageview.cpp
index 3c22ab44..d7749985 100644
--- a/qt4/demos/pageview.cpp
+++ b/qt4/demos/pageview.cpp
@@ -67,6 +67,9 @@ void PageView::pageChanged(int page)
 void PageView::slotZoomChanged(qreal value)
 {
     m_zoom = value;
+    if (!document()) {
+        return;
+    }
     reloadPage();
 }