plot: Convert PlotView to derive from QAbstractScrollArea

mainwindow.cpp

@@ -26,17 +26,13 @@
 MainWindow::MainWindow()
 {
     setWindowTitle(tr("inspectrum"));
-    scrollArea.viewport()->installEventFilter(this);
 
     dock = new SpectrogramControls(tr("Controls"), this);
     dock->setAllowedAreas(Qt::LeftDockWidgetArea | Qt::RightDockWidgetArea);
     addDockWidget(Qt::LeftDockWidgetArea, dock);
 
     plots = new PlotView();
-    QVBoxLayout *layout = new QVBoxLayout;
-    layout->addWidget(plots);
-    scrollArea.setLayout(layout);
-    setCentralWidget(&scrollArea);
+    setCentralWidget(plots);
 }
 
 void MainWindow::openFile(QString fileName)

mainwindow.h

@@ -36,7 +36,6 @@ public slots:
     void openFile(QString fileName);
 
 private:
-    QScrollArea scrollArea;
     SpectrogramControls *dock;
     PlotView *plots;
 };

plotview.cpp

@@ -33,7 +33,7 @@
 
 PlotView::PlotView()
 {
-
+    setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOn);
 }
 
 void PlotView::refreshSources()
@@ -117,7 +117,7 @@ void PlotView::paintEvent(QPaintEvent *event)
     if (lastSample - firstSample <= 0) return;
 
     QRect rect = QRect(0, 0, width(), height());
-    QPainter painter(this);
+    QPainter painter(viewport());
     painter.fillRect(rect, Qt::black);
 
 

plotview.h

@@ -19,12 +19,12 @@
 
 #pragma once
 
-#include <QDockWidget>
+#include <QAbstractScrollArea>
 #include <QPaintEvent>
 #include "inputsource.h"
 #include "plot.h"
 
-class PlotView : public QDockWidget
+class PlotView : public QAbstractScrollArea
 {
     Q_OBJECT