app: add spacebar playback control

Author: Ramen2X

app/viewer/mediapanel.cpp

@@ -44,7 +44,9 @@ MediaPanel::MediaPanel(QWidget *parent) :
 
   m_PlayBtn = new QPushButton(tr("Play"));
   m_PlayBtn->setCheckable(true);
+  m_PlayShortcut = new QShortcut(QKeySequence(Qt::Key_Space), this);
   connect(m_PlayBtn, &QPushButton::clicked, this, &MediaPanel::Play);
+  connect(m_PlayShortcut, &QShortcut::activated, this, [this]() { Play(!IsPlaying()); });
   ctrl_layout->addWidget(m_PlayBtn);
 
   //FinishLayout();

app/viewer/mediapanel.h

@@ -17,6 +17,7 @@ extern "C" {
 #include <QCheckBox>
 #include <QLabel>
 #include <QPushButton>
+#include <QShortcut>
 #include <QSlider>
 #include <QTimer>
 #include "panel.h"
@@ -188,6 +189,7 @@ class MediaPanel : public Panel
 
   QSlider *m_PlayheadSlider;
   QPushButton *m_PlayBtn;
+  QShortcut *m_PlayShortcut;
   QTimer *m_PlaybackTimer;
   qint64 m_PlaybackStart;
   float m_PlaybackOffset;