diff --git a/toonz/sources/toonzqt/schematicviewer.cpp b/toonz/sources/toonzqt/schematicviewer.cpp
index c322e0e..5e3deb1 100644
--- a/toonz/sources/toonzqt/schematicviewer.cpp
+++ b/toonz/sources/toonzqt/schematicviewer.cpp
@@ -426,14 +426,16 @@ void SchematicSceneViewer::zoomQt(bool zoomin, bool resetZoom) {
 */
 void SchematicSceneViewer::changeScale(const QPoint &winPos,
                                        qreal scaleFactor) {
+  int devPixRatio =
+      m_touchDevice == QTouchDevice::TouchScreen ? 1 : getDevPixRatio();
   QPointF startScenePos = m_touchDevice == QTouchDevice::TouchScreen
                               ? mapToScene(winPos)
-                              : winPos * getDevPixRatio();
+                              : winPos * devPixRatio;
   QMatrix scale = QMatrix().scale(scaleFactor, scaleFactor);
   setMatrix(scale, true);
   QPointF endScenePos = m_touchDevice == QTouchDevice::TouchScreen
                             ? mapToScene(winPos)
-                            : winPos * getDevPixRatio();
+                            : winPos * devPixRatio;
   QPointF delta = endScenePos - startScenePos;
   translate(delta.x(), delta.y());
 }