diff --git a/DSView/pv/data/decoderstack.cpp b/DSView/pv/data/decoderstack.cpp
index 51b35c72..47fa6e44 100644
--- a/DSView/pv/data/decoderstack.cpp
+++ b/DSView/pv/data/decoderstack.cpp
@@ -531,8 +531,10 @@ void DecoderStack::decode_data(const uint64_t decode_start, const uint64_t decod
             if (!bCheckEnd){
                 bCheckEnd = true;
 
-                if (end_index >= _snapshot->get_mipmap_sample_count()){
-                    end_index = _snapshot->get_mipmap_sample_count() - 1;
+                uint64_t mipmap_sample_count = _snapshot->get_mipmap_sample_count();
+
+                if (end_index >= mipmap_sample_count){
+                    end_index = mipmap_sample_count - 1;
                     dsv_info("Reset the decode end sample, new:%llu, old:%llu", end_index, decode_end);
                 }
             }
diff --git a/DSView/pv/data/logicsnapshot.cpp b/DSView/pv/data/logicsnapshot.cpp
index caf320ef..08593677 100644
--- a/DSView/pv/data/logicsnapshot.cpp
+++ b/DSView/pv/data/logicsnapshot.cpp
@@ -506,12 +506,17 @@ void LogicSnapshot::calc_mipmap(unsigned int order, uint8_t index0, uint8_t inde
 
 const uint8_t *LogicSnapshot::get_samples(uint64_t start_sample, uint64_t &end_sample, int sig_index)
 { 
-    assert(start_sample < _ring_sample_count);
-    assert(start_sample <= end_sample);
+    std::lock_guard<std::mutex> lock(_mutex);
 
-    if (end_sample >= _ring_sample_count){
-        end_sample = _ring_sample_count - 1;
-    }
+    uint64_t sample_count = _ring_sample_count;
+
+    assert(start_sample < sample_count);
+
+    if (end_sample >= sample_count)
+        end_sample = sample_count - 1;
+
+    assert(end_sample <= sample_count);
+    assert(start_sample <= end_sample);
 
     int order = get_ch_order(sig_index);
     uint64_t index0 = start_sample >> (LeafBlockPower + RootScalePower);
@@ -522,7 +527,7 @@ const uint8_t *LogicSnapshot::get_samples(uint64_t start_sample, uint64_t &end_s
                  (index1 << LeafBlockPower) +
                  ~(~0ULL << LeafBlockPower);
 
-    end_sample = min(end_sample + 1, _ring_sample_count);
+    end_sample = min(end_sample + 1, sample_count);
 
     if (order == -1 || _ch_data[order][index0].lbp[index1] == NULL)
         return NULL;
@@ -534,12 +539,15 @@ const uint8_t *LogicSnapshot::get_decode_samples(uint64_t start_sample, uint64_t
 { 
     std::lock_guard<std::mutex> lock(_mutex);
 
-    assert(start_sample < _mipmap_sample_count);
-    assert(start_sample <= end_sample);
+    uint64_t sample_count = _mipmap_sample_count;
 
-    if (end_sample >= _mipmap_sample_count){
-        end_sample = _mipmap_sample_count - 1;
-    }
+    assert(start_sample < sample_count);
+
+    if (end_sample >= sample_count)
+        end_sample = sample_count - 1;
+
+    assert(end_sample <= sample_count);
+    assert(start_sample <= end_sample);
 
     int order = get_ch_order(sig_index);
     uint64_t index0 = start_sample >> (LeafBlockPower + RootScalePower);
@@ -550,7 +558,7 @@ const uint8_t *LogicSnapshot::get_decode_samples(uint64_t start_sample, uint64_t
                  (index1 << LeafBlockPower) +
                  ~(~0ULL << LeafBlockPower);
 
-    end_sample = min(end_sample + 1, _mipmap_sample_count);
+    end_sample = min(end_sample + 1, sample_count);
 
     if (order == -1 || _ch_data[order][index0].lbp[index1] == NULL)
         return NULL;
@@ -1097,7 +1105,7 @@ int LogicSnapshot::get_ch_order(int sig_index)
 
 uint64_t LogicSnapshot::get_mipmap_sample_count()
 {   
-    std::lock_guard<std::mutex> lock(_mutex);
+   // std::lock_guard<std::mutex> lock(_mutex);
     return _mipmap_sample_count;
 }
 
diff --git a/DSView/pv/view/logicsignal.cpp b/DSView/pv/view/logicsignal.cpp
index f50932b3..c9f8de5a 100644
--- a/DSView/pv/view/logicsignal.cpp
+++ b/DSView/pv/view/logicsignal.cpp
@@ -46,6 +46,7 @@ LogicSignal::LogicSignal(data::LogicSnapshot *data,
 {
     _trig = NONTRIG;
     _signal_type = LOGIC_SIGNAL;
+    _paint_align_sample_count = 0;
 }
 
 LogicSignal::LogicSignal(view::LogicSignal *s,
@@ -56,6 +57,7 @@ LogicSignal::LogicSignal(view::LogicSignal *s,
     _trig(s->get_trig())
 {
     _signal_type = LOGIC_SIGNAL;
+    _paint_align_sample_count = 0;
 }
 
 LogicSignal::~LogicSignal()
@@ -95,6 +97,17 @@ bool LogicSignal::commit_trig()
 }
 
 void LogicSignal::paint_mid(QPainter &p, int left, int right, QColor fore, QColor back)
+{
+    uint64_t end_align_sample = _data->get_ring_sample_count() - 1;
+    paint_mid_align(p, left, right, fore, back, end_align_sample);
+}
+
+void LogicSignal::paint_mid_align_sample(QPainter &p, int left, int right, QColor fore, QColor back, uint64_t end_align_sample)
+{
+    paint_mid_align(p, left, right, fore, back, end_align_sample);
+}
+
+void LogicSignal::paint_mid_align(QPainter &p, int left, int right, QColor fore, QColor back, uint64_t end_align_sample)
 {
 	using pv::view::View;
 
@@ -119,7 +132,10 @@ void LogicSignal::paint_mid(QPainter &p, int left, int right, QColor fore, QColo
     if (!_data->has_data(_probe->index))
         return;
 
-    const int64_t last_sample = _data->get_ring_sample_count() - 1;
+    if (end_align_sample >= _data->get_ring_sample_count())
+        end_align_sample = _data->get_ring_sample_count() - 1;
+
+    const int64_t last_sample = end_align_sample;
 	const double samples_per_pixel = samplerate * scale;
 
     uint16_t width = right - left;
diff --git a/DSView/pv/view/logicsignal.h b/DSView/pv/view/logicsignal.h
index 3619cfea..d902d13a 100644
--- a/DSView/pv/view/logicsignal.h
+++ b/DSView/pv/view/logicsignal.h
@@ -107,21 +107,25 @@ public:
 
     void paint_mark(QPainter &p, int xstart, int xend, int type);
 
+    void paint_mid_align_sample(QPainter &p, int left, int right, QColor fore, QColor back, uint64_t end_align_sample);
+
 protected:
     void paint_type_options(QPainter &p, int right, const QPoint pt, QColor fore);
 
 private:
-
 	void paint_caps(QPainter &p, QLineF *const lines,
         std::vector< std::pair<uint64_t, bool> > &edges,
 		bool level, double samples_per_pixel, double pixels_offset,
 		float x_offset, float y_offset);
 
+    void paint_mid_align(QPainter &p, int left, int right, QColor fore, QColor back, uint64_t end_align_sample);
+
 private:
 	pv::data::LogicSnapshot* _data;
     std::vector< std::pair<uint16_t, bool> > _cur_edges;
     std::vector<std::pair<bool, bool>> _cur_pulses;
     LogicSetRegions _trig;
+    uint64_t    _paint_align_sample_count;
 };
 
 } // namespace view
diff --git a/DSView/pv/view/signal.cpp b/DSView/pv/view/signal.cpp
index 9377e07f..cbd69482 100644
--- a/DSView/pv/view/signal.cpp
+++ b/DSView/pv/view/signal.cpp
@@ -34,8 +34,7 @@ namespace view {
 Signal::Signal(sr_channel *probe) :
     Trace(probe->name, probe->index, probe->type),
     _probe(probe)
-{   
-    _signal_type = UNKNOWN_SIGNAL;
+{
     session = AppControl::Instance()->GetSession();
 }
 
@@ -43,7 +42,6 @@ Signal::Signal(const Signal &s, sr_channel *probe) :
     Trace((const Trace &)s), 
     _probe(probe)
 {   
-    _signal_type = UNKNOWN_SIGNAL;
     session = AppControl::Instance()->GetSession();
 }
 
diff --git a/DSView/pv/view/signal.h b/DSView/pv/view/signal.h
index ee0ba95a..464a0933 100644
--- a/DSView/pv/view/signal.h
+++ b/DSView/pv/view/signal.h
@@ -37,14 +37,6 @@
 #include <libsigrok.h> 
 #include "trace.h"
 
-enum SIGNAL_TYPE
-{   
-    UNKNOWN_SIGNAL = 0,
-    LOGIC_SIGNAL = 1,
-    DSO_SIGNAL = 2,
-    ANALOG_SIGNAL = 3,   
-};
-
 namespace pv {
 
 namespace data {
@@ -82,14 +74,10 @@ public:
      */
     void set_name(QString name);
 
-    inline SIGNAL_TYPE signal_type(){
-        return _signal_type;
-    }
 
 protected: 
     sr_channel *const _probe;
-    SigSession      *session;
-    SIGNAL_TYPE     _signal_type;
+    SigSession      *session;    
 };
 
 } // namespace view
diff --git a/DSView/pv/view/trace.cpp b/DSView/pv/view/trace.cpp
index af1cc03d..62bf8f7a 100644
--- a/DSView/pv/view/trace.cpp
+++ b/DSView/pv/view/trace.cpp
@@ -58,6 +58,7 @@ Trace::Trace(QString name, uint16_t index, int type) :
     _typeWidth(SquareNum)
 {
     _index_list.push_back(index);
+    _signal_type = UNKNOWN_SIGNAL;
 }
 
 Trace::Trace(QString name, std::list<int> index_list, int type, int sec_index) :
@@ -70,6 +71,7 @@ Trace::Trace(QString name, std::list<int> index_list, int type, int sec_index) :
     _totalHeight(30),
     _typeWidth(SquareNum)
 {
+    _signal_type = UNKNOWN_SIGNAL;
 }
 
 Trace::Trace(const Trace &t) :
@@ -85,6 +87,7 @@ Trace::Trace(const Trace &t) :
     _typeWidth(t._typeWidth),
     _text_size(t._text_size)
 {
+    _signal_type = UNKNOWN_SIGNAL;
 }
 
 QString Trace::get_name()
diff --git a/DSView/pv/view/trace.h b/DSView/pv/view/trace.h
index 42f57d5c..27db40f1 100644
--- a/DSView/pv/view/trace.h
+++ b/DSView/pv/view/trace.h
@@ -36,6 +36,14 @@
 
 class QFormLayout;
 
+enum SIGNAL_TYPE
+{   
+    UNKNOWN_SIGNAL = 0,
+    LOGIC_SIGNAL = 1,
+    DSO_SIGNAL = 2,
+    ANALOG_SIGNAL = 3,   
+};
+
 namespace pv {
 namespace view {
 
@@ -235,6 +243,10 @@ public:
 
     virtual bool mouse_wheel(int right, const QPoint pt, const int shift);
 
+    inline SIGNAL_TYPE signal_type(){
+        return _signal_type;
+    }
+
 protected:
 
 	/**
@@ -286,6 +298,7 @@ protected:
     int _typeWidth;
 
     QSizeF _text_size;
+    SIGNAL_TYPE     _signal_type;   
 };
 
 } // namespace view
diff --git a/DSView/pv/view/viewport.cpp b/DSView/pv/view/viewport.cpp
index a4c06a1e..1ee07495 100644
--- a/DSView/pv/view/viewport.cpp
+++ b/DSView/pv/view/viewport.cpp
@@ -251,9 +251,19 @@ void Viewport::paintSignals(QPainter &p, QColor fore, QColor back)
 
     if (_view.session().get_device()->get_work_mode() == LOGIC) 
     {
+        bool bFirst = true;
+        uint64_t end_align_sample;
+
         for(auto t : traces){
-            if (t->enabled())
-                t->paint_mid(p, 0, t->get_view_rect().right(), fore, back);
+            if (t->enabled()){
+                LogicSignal *logic_signal = (LogicSignal*)t;
+                
+                if (bFirst)
+                    end_align_sample = logic_signal->data()->get_ring_sample_count();
+        
+                logic_signal->paint_mid_align_sample(p, 0, t->get_view_rect().right(), fore, back, end_align_sample);
+                bFirst = false;
+            }                
         }
     } 
     else {
@@ -273,7 +283,7 @@ void Viewport::paintSignals(QPainter &p, QColor fore, QColor back)
             for(auto t : traces)
             {
                 if (t->enabled())
-                    t->paint_mid(dbp, 0, t->get_view_rect().right(), fore, back); 
+                    t->paint_mid(dbp, 0, t->get_view_rect().right(), fore, back);
             }
             _need_update = false;
         }