Reinstate **View > Scanner** top-bar menu action.

This checkable menu action was removed in dd7a5ad, as it was
deemed redundant after the main vertical splitter was added in
76e3b2e. However, it turned out that this convenience action
was quite popular, and users have requested it back.

An effort has been made to preserve the splitter's position when the
scanner's visibility is toggled.

Bonus: The action has been assigned the `S` keyboard shortcut.

Fixes #102.

Source/GUI/MainWindow.cpp

@@ -73,6 +73,10 @@ void MainWindow::makeMenus()
 
   m_actMemoryViewer = new QAction(tr("&Memory Viewer"), this);
   m_actCopyMemory = new QAction(tr("&Copy Memory Range"), this);
+  m_actScanner = new QAction(tr("&Scanner"), this);
+  m_actScanner->setShortcut(QKeySequence("S"));
+  m_actScanner->setCheckable(true);
+  m_actScanner->setChecked(m_splitter->sizes()[0] > 0);
 
   m_actQuit = new QAction(tr("&Quit"), this);
   m_actAbout = new QAction(tr("&About"), this);
@@ -91,6 +95,7 @@ void MainWindow::makeMenus()
 
   connect(m_actMemoryViewer, &QAction::triggered, this, &MainWindow::onOpenMenViewer);
   connect(m_actCopyMemory, &QAction::triggered, this, &MainWindow::onCopyMemory);
+  connect(m_actScanner, &QAction::toggled, this, &MainWindow::onScannerActionToggled);
 
   connect(m_actQuit, &QAction::triggered, this, &MainWindow::onQuit);
   connect(m_actAbout, &QAction::triggered, this, &MainWindow::onAbout);
@@ -116,6 +121,7 @@ void MainWindow::makeMenus()
   m_menuView = menuBar()->addMenu(tr("&View"));
   m_menuView->addAction(m_actMemoryViewer);
   m_menuView->addAction(m_actCopyMemory);
+  m_menuView->addAction(m_actScanner);
 
   m_menuHelp = menuBar()->addMenu(tr("&Help"));
   m_menuHelp->addAction(m_actAbout);
@@ -358,6 +364,21 @@ void MainWindow::onHookIfNotHooked()
 void MainWindow::onSplitterMoved(const int pos, const int index)
 {
   SConfig::getInstance().setSplitterState(m_splitter->saveState());
+
+  const QList<int> currentSizes{m_splitter->sizes()};
+  const int totalSize{std::accumulate(currentSizes.begin(), currentSizes.end(), 0)};
+  const double scannerSize{static_cast<double>(currentSizes[0])};
+  const bool scannerVisible{scannerSize > 0};
+  if (scannerVisible)
+  {
+    const double scannerFactor{scannerSize / static_cast<double>(totalSize)};
+    m_splitter->setProperty("previous_scanner_factor", scannerFactor);
+  }
+
+  {
+    QSignalBlocker signalBlocker(m_actScanner);
+    m_actScanner->setChecked(scannerVisible);
+  }
 }
 
 void MainWindow::onOpenWatchFile()
@@ -397,6 +418,33 @@ void MainWindow::onCopyMemory()
   m_copier->raise();
 }
 
+void MainWindow::onScannerActionToggled(const bool checked)
+{
+  const QList<int> currentSizes{m_splitter->sizes()};
+  const int totalSize{std::accumulate(currentSizes.begin(), currentSizes.end(), 0)};
+
+  QList<int> sizes;
+  if (!checked)
+  {
+    const double scannerSize{static_cast<double>(currentSizes[0])};
+    const double scannerFactor{scannerSize / static_cast<double>(totalSize)};
+    m_splitter->setProperty("previous_scanner_factor", scannerFactor);
+
+    sizes << 0 << totalSize;
+  }
+  else
+  {
+    const QVariant scannerFactorVariant{m_splitter->property("previous_scanner_factor")};
+    const double scannerFactor{scannerFactorVariant.isValid() ? scannerFactorVariant.toDouble() :
+                                                                0.5};
+    const double scannerSize{std::round(scannerFactor * totalSize)};
+
+    sizes << scannerSize << totalSize - scannerSize;
+  }
+
+  m_splitter->setSizes(sizes);
+}
+
 void MainWindow::onOpenSettings()
 {
   DlgSettings* dlg = new DlgSettings(this);

Source/GUI/MainWindow.h

@@ -46,6 +46,7 @@ class MainWindow : public QMainWindow
   void onImportFromCT();
   void onExportAsCSV();
   void onCopyMemory();
+  void onScannerActionToggled(bool checked);
   void onAbout();
   void onQuit();
 
@@ -84,6 +85,7 @@ class MainWindow : public QMainWindow
   QAction* m_actUnhook;
   QAction* m_actMemoryViewer;
   QAction* m_actCopyMemory;
+  QAction* m_actScanner{};
   QAction* m_actQuit;
   QAction* m_actAbout;
 };