footageviewer: auto switch waveform mode when clicking video/audio buttons

app/widget/playbackcontrols/dragbutton.cpp

@@ -1,7 +1,7 @@
 /***
 
   Olive - Non-Linear Video Editor
-  Copyright (C) 2022 Olive Team
+  Copyright (C) 2023 Olive Studios LLC
 
   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -20,18 +20,37 @@
 
 #include "dragbutton.h"
 
+#include <QMouseEvent>
+
 namespace olive {
 
 DragButton::DragButton(QWidget *parent) :
   QPushButton(parent)
 {
   setCursor(Qt::OpenHandCursor);
+  dragging_ = false;
 }
 
-void DragButton::mousePressEvent(QMouseEvent *event) {
+void DragButton::mousePressEvent(QMouseEvent *event)
+{
   QPushButton::mousePressEvent(event);
+}
 
-  emit MousePressed();
+void DragButton::mouseMoveEvent(QMouseEvent *event)
+{
+  QPushButton::mouseMoveEvent(event);
+
+  if (event->buttons() && !dragging_) {
+    emit DragStarted();
+    dragging_ = true;
+  }
+}
+
+void DragButton::mouseReleaseEvent(QMouseEvent *event)
+{
+  QPushButton::mouseReleaseEvent(event);
+
+  dragging_ = false;
 }
 
 }