waveformview: implemented basic waveformview display

2020-03-14 01:22:03 +11:00
parent f0e6f9a5f9
commit 73d693f2d5
6 changed files with 176 additions and 51 deletions
@@ -1,24 +1,148 @@
 #include "waveformview.h"

+#include <QFile>
 #include <QPainter>
 #include <QtMath>

+#include "common/clamp.h"
+
 WaveformView::WaveformView(QWidget *parent) :
-  TimeBasedWidget(parent)
+  TimelineScaledWidget(parent),
+  backend_(nullptr)
 {
  setAutoFillBackground(true);
-  setStyleSheet("background: black;");
+  setBackgroundRole(QPalette::Base);
+}
+
+void WaveformView::SetBackend(AudioRenderBackend *backend)
+{
+  if (backend_) {
+    disconnect(backend_, &AudioRenderBackend::QueueComplete, this, static_cast<void (WaveformView::*)()>(&WaveformView::update));
+  }
+
+  backend_ = backend;
+
+  if (backend_) {
+    connect(backend_, &AudioRenderBackend::QueueComplete, this, static_cast<void (WaveformView::*)()>(&WaveformView::update));
+  }
+
+  update();
+}
+
+void WaveformView::DrawWaveform(QPainter *painter, const QRect& rect, const double& scale, const SampleSummer::Sum* samples, int nb_samples, int channels)
+{
+  int sample_index, next_sample_index = 0;
+
+  QVector<SampleSummer::Sum> summary;
+  int summary_index = -1;
+
+  int channel_height = rect.height() / channels;
+  int channel_half_height = channel_height / 2;
+
+  for (int i=0;i<rect.width();i++) {
+    sample_index = next_sample_index;
+
+    if (sample_index == nb_samples) {
+      break;
+    }
+
+    next_sample_index = qMin(nb_samples,
+                             qFloor(static_cast<double>(SampleSummer::kSumSampleRate) * static_cast<double>(i+1) / scale) * channels);
+
+    if (summary_index != sample_index) {
+      summary = SampleSummer::ReSumSamples(&samples[sample_index],
+                                           qMax(channels, next_sample_index - sample_index),
+                                           channels);
+      summary_index = sample_index;
+    }
+
+    int line_x = i + rect.x();
+
+    for (int j=0;j<summary.size();j++) {
+      int channel_mid = rect.y() + channel_height * j + channel_half_height;
+
+      painter->drawLine(line_x,
+                        channel_mid + clamp(qRound(summary.at(j).min * channel_half_height), -channel_half_height, channel_half_height),
+                        line_x,
+                        channel_mid + clamp(qRound(summary.at(j).max * channel_half_height), -channel_half_height, channel_half_height));
+    }
+  }
+}
+
+void WaveformView::SetScroll(int scroll)
+{
+  scroll_ = scroll;
+
+  qDebug() << "Got scroll" << scroll_;
+
+  update();
 }

 void WaveformView::paintEvent(QPaintEvent *event)
 {
  QWidget::paintEvent(event);

-  QPainter p(this);
+  if (!backend_ || backend_->CachePathName().isEmpty() || !backend_->params().is_valid()) {
+    return;
+  }

-  p.setPen(Qt::green);
+  const AudioRenderingParams& params = backend_->params();
+
+  QFile fs(backend_->CachePathName());
+
+  if (fs.open(QFile::ReadOnly)) {
+
+    QPainter p(this);
+
+    p.setPen(Qt::green);
+
+    int channel_height = height() / params.channel_count();
+    int channel_half_height = channel_height / 2;
+
+    int drew = 0;
+
+    fs.seek(params.samples_to_bytes(GetSampleIndexFromPixel(0)));
+
+    for (int x=0; x<width() && !fs.atEnd(); x++) {
+
+      int samples_len = GetSampleIndexFromPixel(x+1) - GetSampleIndexFromPixel(x);
+      int max_read_size = params.samples_to_bytes(samples_len);
+
+      QByteArray read_buffer = fs.read(max_read_size);
+
+      // Detect whether we've reached EOF and recalculate sample count if so
+      if (read_buffer.size() < max_read_size) {
+        samples_len = params.bytes_to_samples(read_buffer.size());
+      }
+
+      QVector<SampleSummer::Sum> samples = SampleSummer::SumSamples(reinterpret_cast<const float*>(read_buffer.constData()),
+                                                                    samples_len,
+                                                                    params.channel_count());
+
+      for (int i=0;i<params.channel_count();i++) {
+        int channel_mid = channel_height * i + channel_half_height;
+
+        p.drawLine(x,
+                   channel_mid + samples.at(i).min * static_cast<float>(channel_half_height),
+                   x,
+                   channel_mid + samples.at(i).max * static_cast<float>(channel_half_height));
+
+        drew++;
+      }
+    }
+
+    fs.close();

-  for (int i=0;i<width();i++) {
-    p.drawPoint(i, (height() / 2) + qSin(static_cast<double>(i) * 0.025) * (height() / 2));
  }
 }
+
+void WaveformView::ScaleChangedEvent(const double &)
+{
+  update();
+}
+
+int WaveformView::GetSampleIndexFromPixel(int x) const
+{
+  qDebug() << "X was" << x << "scroll was" << scroll_ << "=" << (x + scroll_);
+  return qRound(static_cast<double>(x + scroll_) * static_cast<double>(backend_->params().sample_rate()) / GetScale());
+}