audiomonitor: use mipmapped waveform

Since we have these now, may as well use them. This should
improve general playback performance since the audio monitor
will be able to iterate far fewer

app/audio/audiomanager.h

@@ -27,6 +27,7 @@
 #include <QtConcurrent/QtConcurrent>
 #include <QThread>
 
+#include "audiovisualwaveform.h"
 #include "common/define.h"
 #include "outputmanager.h"
 #include "render/audioparams.h"
@@ -94,6 +95,8 @@ signals:
 
   void OutputDeviceStarted(AudioPlaybackCache* cache, qint64 offset, int playback_speed);
 
+  void OutputWaveformStarted(const AudioVisualWaveform* waveform, const rational &start, int playback_speed);
+
   void AudioParamsChanged(const AudioParams& params);
 
   void OutputPushed(const QByteArray& data);

app/audio/audiovisualwaveform.cpp

@@ -203,6 +203,19 @@ void AudioVisualWaveform::Shift(const rational &from, const rational &to)
   }
 }
 
+AudioVisualWaveform::Sample AudioVisualWaveform::GetSummaryFromTime(const rational &start, const rational &length) const
+{
+  // Find mipmap that requries
+  auto using_mipmap = GetMipmapForScale(length.flipped().toDouble());
+
+  double rate_dbl = using_mipmap->first.toDouble();
+
+  int start_sample = time_to_samples(start, rate_dbl);
+  int sample_length = time_to_samples(length, rate_dbl);
+
+  return ReSumSamples(&using_mipmap->second.constData()[start_sample], sample_length, channels_);
+}
+
 AudioVisualWaveform::Sample AudioVisualWaveform::SumSamples(const float *samples, int nb_samples, int nb_channels)
 {
   return SumSamplesInternal(samples, nb_samples, nb_channels);
@@ -285,15 +298,7 @@ void AudioVisualWaveform::DrawWaveform(QPainter *painter, const QRect& rect, con
     return;
   }
 
-  // Find largest mipmap for this scale (or the largest if we don't find one sufficient)
-  auto using_mipmap = samples.mipmapped_data_.cend();
-  using_mipmap--;
-  for (auto it=samples.mipmapped_data_.cbegin(); it!=samples.mipmapped_data_.cend(); it++) {
-    if (it->first.toDouble() >= scale) {
-      using_mipmap = it;
-      break;
-    }
-  }
+  auto using_mipmap = samples.GetMipmapForScale(scale);
 
   rational rate = using_mipmap->first;
   double rate_dbl = rate.toDouble();
@@ -350,6 +355,20 @@ int AudioVisualWaveform::time_to_samples(const double &time, double sample_rate)
   return qFloor(time * sample_rate) * channels_;
 }
 
+std::map<rational, AudioVisualWaveform::Sample>::const_iterator AudioVisualWaveform::GetMipmapForScale(double scale) const
+{
+  // Find largest mipmap for this scale (or the largest if we don't find one sufficient)
+  auto using_mipmap = mipmapped_data_.cend();
+  using_mipmap--;
+  for (auto it=mipmapped_data_.cbegin(); it!=mipmapped_data_.cend(); it++) {
+    if (it->first.toDouble() >= scale) {
+      using_mipmap = it;
+      break;
+    }
+  }
+  return using_mipmap;
+}
+
 template<typename T>
 AudioVisualWaveform::Sample AudioVisualWaveform::SumSamplesInternal(const T *samples, int nb_samples, int nb_channels)
 {

app/audio/audiovisualwaveform.h

@@ -85,6 +85,8 @@ public:
 
   void Shift(const rational& from, const rational& to);
 
+  Sample GetSummaryFromTime(const rational& start, const rational& length) const;
+
   static Sample SumSamples(const float* samples, int nb_samples, int nb_channels);
   static Sample SumSamples(SampleBufferPtr samples, int start_index, int length);
 
@@ -108,6 +110,8 @@ private:
   int time_to_samples(const rational& time, double sample_rate) const;
   int time_to_samples(const double& time, double sample_rate) const;
 
+  std::map<rational, Sample>::const_iterator GetMipmapForScale(double scale) const;
+
   int channels_;
 
   std::map<rational, Sample> mipmapped_data_;