diff --git a/mainwindow.cpp b/mainwindow.cpp
index 737f8e9..f2defed 100644
--- a/mainwindow.cpp
+++ b/mainwindow.cpp
@@ -41,6 +41,4 @@ void MainWindow::openFile(QString fileName)
     this->setWindowTitle(title.arg(QApplication::applicationName(),fileName.section('/',-1,-1)));
     // TODO: error check, ownership
     plots->inputSourceChanged(new InputSource(fileName.toUtf8().constData()));
-    // TODO: don't hardcode this
-    plots->viewChanged(0, 102400);
 }
diff --git a/plotview.cpp b/plotview.cpp
index 7f8fca4..6fd9d4d 100644
--- a/plotview.cpp
+++ b/plotview.cpp
@@ -20,6 +20,7 @@
 #include "plotview.h"
 #include <QDebug>
 #include <QPainter>
+#include <QScrollBar>
 #include <gnuradio/top_block.h>
 #include <gnuradio/analog/quadrature_demod_cf.h>
 #include <gnuradio/blocks/multiply_const_cc.h>
@@ -89,13 +90,9 @@ void PlotView::inputSourceChanged(AbstractSampleSource *src)
 
     mainSampleSource = derived;
     refreshSources();
-}
 
-void PlotView::viewChanged(off_t firstSample, off_t lastSample)
-{
-    this->firstSample = firstSample;
-    this->lastSample = lastSample;
-    update();
+    horizontalScrollBar()->setMinimum(0);
+    horizontalScrollBar()->setMaximum(mainSampleSource->count());
 }
 
 void PlotView::selectionChanged(std::pair<off_t, off_t> selectionTime, std::pair<float, float> selectionFreq)
@@ -114,7 +111,10 @@ void PlotView::selectionCleared()
 
 void PlotView::paintEvent(QPaintEvent *event)
 {
-    if (lastSample - firstSample <= 0) return;
+    if (mainSampleSource == nullptr) return;
+    off_t firstSample = horizontalScrollBar()->value();
+    // TODO: don't hardcode width
+    off_t lastSample = firstSample + 10240;
 
     QRect rect = QRect(0, 0, width(), height());
     QPainter painter(viewport());
diff --git a/plotview.h b/plotview.h
index 2600ade..72ead19 100644
--- a/plotview.h
+++ b/plotview.h
@@ -33,7 +33,6 @@ public:
 
 public slots:
     void inputSourceChanged(AbstractSampleSource *input);
-    void viewChanged(off_t firstSample, off_t lastSample);
     void selectionChanged(std::pair<off_t, off_t> selectionTime, std::pair<float, float> selectionFreq);
     void selectionCleared();
 
@@ -43,8 +42,6 @@ protected:
 private:
     SampleSource<std::complex<float>> *mainSampleSource = nullptr;
     std::vector<std::unique_ptr<Plot>> plots;
-    off_t firstSample = 0;
-    off_t lastSample = 0;
     bool selection = false;
     std::pair<off_t, off_t> selectionTime;
     std::pair<float, float> selectionFreq;