diff --git a/src/plot.cpp b/src/plot.cpp
--- a/src/plot.cpp
+++ b/src/plot.cpp
@@ -1,5 +1,5 @@
 /*
-  Copyright © 2015 Hasan Yavuz Özderya
+  Copyright © 2017 Hasan Yavuz Özderya
 
   This file is part of serialplot.
 
@@ -38,6 +38,7 @@ Plot::Plot(QWidget* parent) :
 {
     isAutoScaled = true;
     symbolSize = 0;
+    numOfSamples = 1;
 
     QObject::connect(&zoomer, &Zoomer::unzoomed, this, &Plot::unzoomed);
 
@@ -78,7 +79,7 @@ Plot::~Plot()
     if (snapshotOverlay != NULL) delete snapshotOverlay;
 }
 
-void Plot::setAxis(bool autoScaled, double yAxisMin, double yAxisMax)
+void Plot::setYAxis(bool autoScaled, double yAxisMin, double yAxisMax)
 {
     this->isAutoScaled = autoScaled;
 
@@ -92,8 +93,29 @@ void Plot::setAxis(bool autoScaled, doub
     resetAxes();
 }
 
+void Plot::setXAxis(double xMin, double xMax)
+{
+    _xMin = xMin;
+    _xMax = xMax;
+
+    zoomer.zoom(0); // unzoom
+
+    // set axis
+    setAxisScale(QwtPlot::xBottom, xMin, xMax);
+    replot(); // Note: if we don't replot here scale at startup isn't set correctly
+
+    // reset zoom base
+    auto base = zoomer.zoomBase();
+    base.setLeft(xMin);
+    base.setRight(xMax);
+    zoomer.setZoomBase(base);
+
+    onXScaleChanged();
+}
+
 void Plot::resetAxes()
 {
+    // reset y axis
     if (isAutoScaled)
     {
         setAxisAutoScale(QwtPlot::yLeft);
@@ -103,12 +125,13 @@ void Plot::resetAxes()
         setAxisScale(QwtPlot::yLeft, yMin, yMax);
     }
 
+    zoomer.setZoomBase();
+
     replot();
 }
 
 void Plot::unzoomed()
 {
-    setAxisAutoScale(QwtPlot::xBottom);
     resetAxes();
     onXScaleChanged();
 }
@@ -229,7 +252,10 @@ void Plot::onXScaleChanged()
     auto sw = axisWidget(QwtPlot::xBottom);
     auto paintDist = sw->scaleDraw()->scaleMap().pDist();
     auto scaleDist = sw->scaleDraw()->scaleMap().sDist();
-    int symDisPx = round(paintDist / scaleDist);
+    auto fullScaleDist = zoomer.zoomBase().width();
+    auto zoomRate = fullScaleDist / scaleDist;
+    float samplesInView = numOfSamples / zoomRate;
+    int symDisPx = round(paintDist / samplesInView);
 
     if (symDisPx < SYMBOL_SHOW_AT_WIDTH)
     {
@@ -273,8 +299,6 @@ void Plot::resizeEvent(QResizeEvent * ev
 
 void Plot::onNumOfSamplesChanged(unsigned value)
 {
-    auto currentBase = zoomer.zoomBase();
-    currentBase.setWidth(value);
-    zoomer.setZoomBase(currentBase);
+    numOfSamples = value;
     onXScaleChanged();
 }