viewer: began waveformview widget

app/widget/viewer/CMakeLists.txt

@@ -24,5 +24,7 @@ set(OLIVE_SOURCES
   widget/viewer/viewerglwidget.cpp
   widget/viewer/viewersizer.h
   widget/viewer/viewersizer.cpp
+  widget/viewer/waveformview.h
+  widget/viewer/waveformview.cpp
   PARENT_SCOPE
 )

app/widget/viewer/viewer.cpp

@@ -60,9 +60,8 @@ ViewerWidget::ViewerWidget(QWidget *parent) :
   sizer_->SetWidget(gl_widget_);
 
   // Create waveform view when audio is connected and video isn't
-  waveform_view_ = new QWidget();
-  waveform_view_->setAutoFillBackground(true);
-  waveform_view_->setStyleSheet("background: black;");
+  waveform_view_ = new WaveformView();
+
   stack_->addWidget(waveform_view_);
 
   // Create time ruler

app/widget/viewer/viewer.h

@@ -35,6 +35,7 @@
 #include "render/backend/audio/audiobackend.h"
 #include "viewerglwidget.h"
 #include "viewersizer.h"
+#include "waveformview.h"
 #include "widget/playbackcontrols/playbackcontrols.h"
 #include "widget/timebased/timebased.h"
 
@@ -154,7 +155,7 @@ private:
 
   bool time_changed_from_timer_;
 
-  QWidget* waveform_view_;
+  WaveformView* waveform_view_;
 
 private slots:
   void PlaybackTimerUpdate();

app/widget/viewer/waveformview.cpp

@@ -0,0 +1,24 @@
+#include "waveformview.h"
+
+#include <QPainter>
+#include <QtMath>
+
+WaveformView::WaveformView(QWidget *parent) :
+  TimeBasedWidget(parent)
+{
+  setAutoFillBackground(true);
+  setStyleSheet("background: black;");
+}
+
+void WaveformView::paintEvent(QPaintEvent *event)
+{
+  QWidget::paintEvent(event);
+
+  QPainter p(this);
+
+  p.setPen(Qt::green);
+
+  for (int i=0;i<width();i++) {
+    p.drawPoint(i, (height() / 2) + qSin(static_cast<double>(i) * 0.025) * (height() / 2));
+  }
+}

app/widget/viewer/waveformview.h

@@ -0,0 +1,16 @@
+#ifndef WAVEFORMVIEW_H
+#define WAVEFORMVIEW_H
+
+#include "widget/timebased/timebased.h"
+
+class WaveformView : public TimeBasedWidget
+{
+public:
+  WaveformView(QWidget* parent = nullptr);
+
+protected:
+  virtual void paintEvent(QPaintEvent* event) override;
+
+};
+
+#endif // WAVEFORMVIEW_H