diff --git a/DSView/pv/view/view.cpp b/DSView/pv/view/view.cpp
index ef1e2f69..dfb54480 100644
--- a/DSView/pv/view/view.cpp
+++ b/DSView/pv/view/view.cpp
@@ -226,10 +226,7 @@ void View::zoom(double steps, int offset)
             }
         }
         _offset = cursor_offset - _scale * offset;
-        const double MinOffset = -(_scale * (get_view_width() * (1 - MaxViewRate)));
-        const double MaxOffset = _session.get_device()->get_sample_time() -
-                _scale * (get_view_width() * MaxViewRate);
-        _offset = max(min(_offset, MaxOffset), MinOffset);
+        _offset = max(min(_offset, get_max_offset()), get_min_offset());
 
         if (_scale != _preScale || _offset != _preOffset) {
             _header->update();
@@ -248,11 +245,7 @@ void View::set_scale_offset(double scale, double offset)
         _preOffset = _offset;
 
         _scale = max(min(scale, _maxscale), _minscale);
-
-        const double MinOffset = -(_scale * (get_view_width() * (1 - MaxViewRate)));
-        const double MaxOffset = _session.get_device()->get_sample_time()
-                - _scale * (get_view_width() * MaxViewRate);
-        _offset = max(min(offset, MaxOffset), MinOffset);
+        _offset = max(min(offset, get_max_offset()), get_min_offset());
 
         if (_scale != _preScale || _offset != _preOffset) {
             update_scroll();
@@ -604,10 +597,6 @@ void View::h_scroll_value_changed(int value)
 
     _preOffset = _offset;
 
-    const double MinOffset = -(_scale * (get_view_width() * (1 - MaxViewRate)));
-    const double MaxOffset = _session.get_device()->get_sample_time()
-            - _scale * (get_view_width() * MaxViewRate);
-
 	const int range = horizontalScrollBar()->maximum();
 	if (range < MaxScrollValue)
 		_offset = _scale * value;
@@ -617,7 +606,7 @@ void View::h_scroll_value_changed(int value)
 		_offset = _scale * length * value / MaxScrollValue;
 	}
 
-    _offset = max(min(_offset, MaxOffset), MinOffset);
+    _offset = max(min(_offset, get_max_offset()), get_min_offset());
 
     if (_offset != _preOffset) {
         _ruler->update();
@@ -796,5 +785,16 @@ int View::get_view_width()
     return view_width;
 }
 
+double View::get_min_offset()
+{
+    return -(_scale * (get_view_width() * (1 - MaxViewRate)));
+}
+
+double View::get_max_offset()
+{
+    return _session.get_device()->get_sample_time()
+            - _scale * (get_view_width() * MaxViewRate);
+}
+
 } // namespace view
 } // namespace pv
diff --git a/DSView/pv/view/view.h b/DSView/pv/view/view.h
index 81bffcb2..460de3b8 100644
--- a/DSView/pv/view/view.h
+++ b/DSView/pv/view/view.h
@@ -95,6 +95,9 @@ public:
 	double offset() const;
 	int v_offset() const;
 
+    double get_min_offset();
+    double get_max_offset();
+
 	void zoom(double steps);
 	void zoom(double steps, int offset);
 
diff --git a/DSView/pv/view/viewport.cpp b/DSView/pv/view/viewport.cpp
index d8d8351f..ba36d329 100644
--- a/DSView/pv/view/viewport.cpp
+++ b/DSView/pv/view/viewport.cpp
@@ -46,6 +46,9 @@ using namespace std;
 namespace pv {
 namespace view {
 
+const double Viewport::DragDamping = 1.05;
+const double Viewport::MinorDragRateUp = 10;
+
 Viewport::Viewport(View &parent) :
 	QWidget(&parent),
         _view(parent),
@@ -74,10 +77,16 @@ Viewport::Viewport(View &parent) :
     triggered = false;
     timer_cnt = 0;
 
+    // drag inertial
+    _drag_strength = 0;
+    _drag_timer.setSingleShot(true);
+
     connect(&_view, SIGNAL(traces_moved()),
         this, SLOT(on_traces_moved()));
     connect(&trigger_timer, SIGNAL(timeout()),
             this, SLOT(on_trigger_timer()));
+    connect(&_drag_timer, SIGNAL(timeout()),
+            this, SLOT(on_drag_timer()));
 
     connect(&_view.session(), &SigSession::receive_data,
             this, &Viewport::set_receive_len);
@@ -355,6 +364,8 @@ void Viewport::mousePressEvent(QMouseEvent *event)
 	_mouse_down_point = event->pos();
 	_mouse_down_offset = _view.offset();
     _measure_shown = false;
+    _drag_strength = 0;
+    _time.start();
 
     if (event->buttons() & Qt::LeftButton) {
         if (_view.cursors_shown()) {
@@ -392,7 +403,6 @@ void Viewport::mousePressEvent(QMouseEvent *event)
 void Viewport::mouseMoveEvent(QMouseEvent *event)
 {
 	assert(event);
-    _mouse_point = event->pos();
     _hover_hit = false;
     if (event->buttons() & Qt::RightButton) {
         _zoom_rect = QRectF(_mouse_down_point, event->pos());
@@ -403,12 +413,13 @@ void Viewport::mouseMoveEvent(QMouseEvent *event)
         if (_drag_sig) {
             boost::shared_ptr<view::DsoSignal> dsoSig;
             if (dsoSig = dynamic_pointer_cast<view::DsoSignal>(_drag_sig))
-                dsoSig->set_trig_vpos(_mouse_point.y());
+                dsoSig->set_trig_vpos(event->pos().y());
         } else {
             _view.set_scale_offset(_view.scale(),
                 _mouse_down_offset +
                 (_mouse_down_point - event->pos()).x() *
                 _view.scale());
+            _drag_strength = (_mouse_down_point - event->pos()).x();
             measure();
         }
     }
@@ -428,6 +439,7 @@ void Viewport::mouseMoveEvent(QMouseEvent *event)
         measure();
     }
 
+    _mouse_point = event->pos();
     update();
 }
 
@@ -454,6 +466,18 @@ void Viewport::mouseReleaseEvent(QMouseEvent *event)
         _hover_hit = false;
     }
 
+    const double strength = _drag_strength*DragTimerInterval*1.0/_time.elapsed();
+    if (_drag_strength < MinorDragOffsetUp && abs(strength) > MinorDragRateUp) {
+        _drag_strength = _drag_strength;
+        _drag_timer.start(DragTimerInterval);
+    } else if (abs(strength) > 0.5*DragTimerInterval) {
+        _drag_strength = strength * 5;
+        _drag_timer.start(DragTimerInterval);
+    } else {
+        _drag_strength = 0;
+        _drag_timer.stop();
+    }
+
     update();
 }
 
@@ -520,7 +544,8 @@ void Viewport::set_receive_len(quint64 length)
 
 void Viewport::measure()
 {
-   if (_view.session().get_capture_state() == SigSession::Running)
+   if (_view.session().get_capture_state() == SigSession::Running ||
+       _drag_strength != 0)
        return;
    _measure_shown = false;
    const uint64_t sample_rate = _view.session().get_device()->get_sample_rate();
@@ -723,5 +748,22 @@ void Viewport::on_trigger_timer()
     update();
 }
 
+void Viewport::on_drag_timer()
+{
+    const double offset = _view.offset();
+    const double scale = _view.scale();
+    if (_view.session().get_capture_state() == SigSession::Stopped &&
+        _drag_strength != 0 &&
+        offset < _view.get_max_offset() &&
+        offset > _view.get_min_offset()) {
+        _view.set_scale_offset(scale, offset + _drag_strength * scale);
+        _drag_strength /= DragDamping;
+        if (_drag_strength != 0)
+            _drag_timer.start(DragTimerInterval);
+    } else {
+        _drag_timer.stop();
+    }
+}
+
 } // namespace view
 } // namespace pv
diff --git a/DSView/pv/view/viewport.h b/DSView/pv/view/viewport.h
index 4899577b..fb959d2f 100644
--- a/DSView/pv/view/viewport.h
+++ b/DSView/pv/view/viewport.h
@@ -27,6 +27,7 @@
 #include <boost/shared_ptr.hpp>
 #include <boost/weak_ptr.hpp>
 
+#include <QTime>
 #include <QTimer>
 #include <QWidget>
 #include <stdint.h>
@@ -48,6 +49,10 @@ class Viewport : public QWidget
 public:
     static const int HitCursorMargin = 10;
     static const double HitCursorTimeMargin;
+    static const int DragTimerInterval = 100;
+    static const int MinorDragOffsetUp = 100;
+    static const double MinorDragRateUp;
+    static const double DragDamping;
 
 public:
 	explicit Viewport(View &parent);
@@ -83,6 +88,7 @@ private:
 private slots:
     void on_traces_moved();
     void on_trigger_timer();
+    void on_drag_timer();
     void set_receive_len(quint64 length);
 
 signals:
@@ -127,6 +133,10 @@ private:
 
     uint64_t _hover_index;
     bool _hover_hit;
+
+    QTime _time;
+    QTimer _drag_timer;
+    int _drag_strength;
 };
 
 } // namespace view