waveformview: implemented basic waveformview display

app/widget/viewer/waveformview.h

@@ -1,16 +1,40 @@
 #ifndef WAVEFORMVIEW_H
 #define WAVEFORMVIEW_H
 
-#include "widget/timebased/timebased.h"
+#include <QWidget>
 
-class WaveformView : public TimeBasedWidget
+#include "audio/sumsamples.h"
+#include "render/audioparams.h"
+#include "render/backend/audiorenderbackend.h"
+#include "widget/timelinewidget/timelinescaledobject.h"
+
+class WaveformView : public TimelineScaledWidget
 {
+  Q_OBJECT
 public:
   WaveformView(QWidget* parent = nullptr);
 
+  //void SetData(const QString& file, const AudioRenderingParams& params);
+
+  void SetBackend(AudioRenderBackend* backend);
+
+  static void DrawWaveform(QPainter* painter, const QRect &rect, const double &scale, const SampleSummer::Sum *samples, int nb_samples, int channels);
+
+public slots:
+  void SetScroll(int scroll);
+
 protected:
   virtual void paintEvent(QPaintEvent* event) override;
 
+  virtual void ScaleChangedEvent(const double& s) override;
+
+private:
+  int GetSampleIndexFromPixel(int x) const;
+
+  AudioRenderBackend* backend_;
+
+  int scroll_;
+
 };
 
 #endif // WAVEFORMVIEW_H