viewer: minor profiling

Allows users to show FPS counter and skipped frames count.

app/widget/viewer/viewer.cpp

@@ -410,6 +410,8 @@ void ViewerWidget::UpdateTextureFromNode(const rational& time)
     // We still run the playback queue even when FrameExistsAtTime returns false because we might be
     // playing backwards and about to start showing frames, so the queue should be prepared for
     // that.
+    bool popped = false;
+
     while (!playback_queue_.empty()) {
 
       const ViewerPlaybackFrame& pf = playback_queue_.front();
@@ -424,6 +426,11 @@ void ViewerWidget::UpdateTextureFromNode(const rational& time)
 
         // Skip this frame
         PopOldestFrameFromPlaybackQueue();
+        if (popped) {
+          // We've already popped a frame in this loop, meaning a frame has been skipped
+          display_widget_->SetSkippedFrames(display_widget_->GetSkippedFrames()+1);
+        }
+        popped = true;
 
       }
     }
@@ -485,6 +492,7 @@ void ViewerWidget::PlayInternal(int speed, bool in_to_out_only)
 
   playback_speed_ = speed;
   play_in_to_out_only_ = in_to_out_only;
+  display_widget_->SetSkippedFrames(0);
 
   playback_queue_next_frame_ = ruler()->GetTime();
 
@@ -651,6 +659,7 @@ void ViewerWidget::FinishPlayPreprocess()
                                         playback_speed_);
 
   playback_timer_.Start(playback_start_time, playback_speed_, timebase_dbl());
+  display_widget_->ResetFPSTimer();
 
   foreach (ViewerWindow* window, windows_) {
     window->Play(playback_start_time, playback_speed_, timebase());
@@ -947,6 +956,13 @@ void ViewerWidget::ShowContextMenu(const QPoint &pos)
     connect(show_waveform_action, &QAction::triggered, this, &ViewerWidget::ManualSwitchToWaveform);
   }
 
+  {
+    QAction* show_fps_action = menu.addAction(tr("Show FPS"));
+    show_fps_action->setCheckable(true);
+    show_fps_action->setChecked(display_widget_->GetShowFPS());
+    connect(show_fps_action, &QAction::triggered, display_widget_, &ViewerDisplayWidget::SetShowFPS);
+  }
+
   menu.exec(static_cast<QWidget*>(sender())->mapToGlobal(pos));
 }
 

app/widget/viewer/viewerdisplay.cpp

@@ -45,7 +45,9 @@ ViewerDisplayWidget::ViewerDisplayWidget(QWidget *parent) :
   gizmo_click_(false),
   last_loaded_buffer_(nullptr),
   hand_dragging_(false),
-  deinterlace_(false)
+  deinterlace_(false),
+  show_fps_(false),
+  frames_skipped_(0)
 {
   connect(Core::instance(), &Core::ToolChanged, this, &ViewerDisplayWidget::UpdateCursor);
 
@@ -181,6 +183,12 @@ QPoint ViewerDisplayWidget::TransformViewerSpaceToBufferSpace(QPoint pos)
   return pos * GenerateGizmoTransform().inverted();
 }
 
+void ViewerDisplayWidget::ResetFPSTimer()
+{
+  fps_timer_start_ = QDateTime::currentMSecsSinceEpoch();
+  fps_timer_update_count_ = 0;
+}
+
 void ViewerDisplayWidget::mousePressEvent(QMouseEvent *event)
 {
   if (event->button() == Qt::LeftButton && gizmos_
@@ -348,6 +356,25 @@ void ViewerDisplayWidget::OnPaint()
 
     p.drawLines(lines, 2);
   }
+
+  if (show_fps_) {
+    QPainter p(inner_widget());
+    fps_timer_update_count_++;
+    qint64 now = QDateTime::currentMSecsSinceEpoch();
+    double frame_rate;
+    if (now == fps_timer_start_) {
+      // This will cause a divide by zero, so we do nothing here
+      frame_rate = 0;
+    } else {
+      frame_rate = double(fps_timer_update_count_) / double((now - fps_timer_start_)/1000.0);
+    }
+    DrawTextWithCrudeShadow(&p, inner_widget()->rect(), tr("%1 FPS").arg(QString::number(frame_rate, 'f', 2)));
+
+    if (frames_skipped_ > 0) {
+      DrawTextWithCrudeShadow(&p, inner_widget()->rect().adjusted(0, p.fontMetrics().height(), 0, 0),
+                              tr("%1 frames skipped").arg(frames_skipped_));
+    }
+  }
 }
 
 void ViewerDisplayWidget::OnDestroy()
@@ -373,6 +400,14 @@ QPointF ViewerDisplayWidget::GetTexturePosition(const double &x, const double &y
                  y / gizmo_params_.height());
 }
 
+void ViewerDisplayWidget::DrawTextWithCrudeShadow(QPainter *painter, const QRect &rect, const QString &text)
+{
+  painter->setPen(Qt::black);
+  painter->drawText(rect.adjusted(1, 1, 0, 0), text);
+  painter->setPen(Qt::white);
+  painter->drawText(rect, text);
+}
+
 rational ViewerDisplayWidget::GetGizmoTime()
 {
   return GetAdjustedTime(GetTimeTarget(), gizmos_, time_, true);
@@ -444,4 +479,11 @@ void ViewerDisplayWidget::EmitColorAtCursor(QMouseEvent *e)
   }
 }
 
+void ViewerDisplayWidget::SetShowFPS(bool e)
+{
+  show_fps_ = e;
+
+  update();
+}
+
 }

app/widget/viewer/viewerdisplay.h

@@ -84,6 +84,23 @@ public:
     return deinterlace_;
   }
 
+  void ResetFPSTimer();
+
+  bool GetShowFPS() const
+  {
+    return show_fps_;
+  }
+
+  int GetSkippedFrames() const
+  {
+    return frames_skipped_;
+  }
+
+  void SetSkippedFrames(int i)
+  {
+    frames_skipped_ = i;
+  }
+
 public slots:
   /**
    * @brief Set the transformation matrix to draw with
@@ -125,6 +142,8 @@ public slots:
    */
   void SetDeinterlacing(bool e);
 
+  void SetShowFPS(bool e);
+
 signals:
   /**
    * @brief Signal emitted when the user starts dragging from the viewer
@@ -167,6 +186,7 @@ protected:
    */
   virtual void mouseReleaseEvent(QMouseEvent* event) override;
 
+protected slots:
   /**
    * @brief Paint function to display the texture (received in SetTexture()) on screen.
    *
@@ -181,6 +201,8 @@ private:
   QPointF GetTexturePosition(const QSize& size);
   QPointF GetTexturePosition(const double& x, const double& y);
 
+  static void DrawTextWithCrudeShadow(QPainter* painter, const QRect& rect, const QString& text);
+
   rational GetGizmoTime();
 
   bool IsHandDrag(QMouseEvent* event) const;
@@ -245,6 +267,12 @@ private:
 
   bool deinterlace_;
 
+  qint64 fps_timer_start_;
+  qint64 fps_timer_update_count_;
+
+  bool show_fps_;
+  int frames_skipped_;
+
 private slots:
   void EmitColorAtCursor(QMouseEvent* e);