Adjust scale limits by dragging the mouse

src/mainwindow.cpp

@@ -54,6 +54,8 @@ MainWindow::MainWindow()
 
     // Connect dock outputs
     connect(plots, &PlotView::timeSelectionChanged, dock, &SpectrogramControls::timeSelectionChanged);
+    connect(plots, &PlotView::adjustPowerContrast, dock, &SpectrogramControls::adjustPowerContrast);
+    connect(plots, &PlotView::adjustPowerBias, dock, &SpectrogramControls::adjustPowerBias);
     connect(plots, &PlotView::zoomIn, dock, &SpectrogramControls::zoomIn);
     connect(plots, &PlotView::zoomOut, dock, &SpectrogramControls::zoomOut);
 

src/plotview.cpp

@@ -238,6 +238,28 @@ bool PlotView::viewportEvent(QEvent *event) {
                 return true;
     }
 
+    if (event->type() == QEvent::MouseMove)
+    {
+        // Handle scale limit adjustments
+        // if Ctrl+Alt pressed, OR middle mouse button is pressed
+        QMouseEvent *mouseEvent = static_cast<QMouseEvent *>(event);
+        if (((QApplication::keyboardModifiers() & Qt::ControlModifier) &&
+              QApplication::keyboardModifiers() & Qt::AltModifier) ||
+            (mouseEvent->buttons() & Qt::MiddleButton)) {
+            int delta_x = mouseEvent->pos().x() - last_x_clicked;
+            int delta_y = last_y_clicked - mouseEvent->pos().y();
+            last_x_clicked = mouseEvent->pos().x();
+            last_y_clicked = mouseEvent->pos().y();
+            if (std::abs(delta_x) > 30 || std::abs(delta_y) > 30)
+            {
+                return true;
+            }
+            emit adjustPowerBias(delta_x);
+            emit adjustPowerContrast(delta_y);
+            return true;
+        }
+    }
+
     // Handle parent eveents
     return QGraphicsView::viewportEvent(event);
 }

src/plotview.h

@@ -39,6 +39,8 @@ class PlotView : public QGraphicsView, Subscriber
 
 signals:
     void timeSelectionChanged(float time);
+    void adjustPowerContrast(int amount);
+    void adjustPowerBias(int amount);
     void zoomIn();
     void zoomOut();
 
@@ -73,6 +75,8 @@ public slots:
 
     int fftSize = 1024;
     int zoomLevel = 1;
+    int last_y_clicked = 0;
+    int last_x_clicked = 0;
     int powerMin;
     int powerMax;
     bool cursorsEnabled;

src/spectrogramcontrols.cpp

@@ -217,6 +217,22 @@ void SpectrogramControls::timeSelectionChanged(float time)
     }
 }
 
+void SpectrogramControls::adjustPowerBias(int amount)
+{
+    if (powerMaxSlider->value() >= 10 || powerMinSlider->value() <= -140)
+    {
+        return;
+    }
+    powerMinSlider->setValue(std::max(std::min(powerMinSlider->value() + amount, 10), -140));
+    powerMaxSlider->setValue(std::max(std::min(powerMaxSlider->value() + amount, 10), -140));
+}
+
+void SpectrogramControls::adjustPowerContrast(int amount)
+{
+    powerMinSlider->setValue(std::max(std::min(powerMinSlider->value() - amount, 10), -140));
+    powerMaxSlider->setValue(std::max(std::min(powerMaxSlider->value() + amount, 10), -140));
+}
+
 void SpectrogramControls::zoomIn()
 {
     zoomLevelSlider->setValue(zoomLevelSlider->value() + 1);

src/spectrogramcontrols.h

@@ -42,6 +42,8 @@ class SpectrogramControls : public QDockWidget
 
 public slots:
     void timeSelectionChanged(float time);
+    void adjustPowerContrast(int amount);
+    void adjustPowerBias(int amount);
     void zoomIn();
     void zoomOut();