Refer from konsole, prohibit to look up the historical information wi…

…th the middle mouse scrolling.

There is url can help understanding new code.
https://invent.kde.org/utilities/konsole/-/commit/17c77a8729336c69bdeff970e3674d929b915b17

For function TerminalDisplay::wheelEvent, I get idea from the latest konsole code.
https://invent.kde.org/utilities/konsole/-/blob/master/src/terminalDisplay/TerminalDisplay.cpp#L1662

lib/Emulation.cpp

@@ -118,6 +118,11 @@ ScreenWindow* Emulation::createWindow()
     return window;
 }
 
+void Emulation::checkScreenInUse()
+{
+    emit primaryScreenInUse(_currentScreen == _screen[0]);
+}
+
 Emulation::~Emulation()
 {
   QListIterator<ScreenWindow*> windowIter(_windows);
@@ -141,6 +146,7 @@ void Emulation::setScreen(int n)
      // tell all windows onto this emulation to switch to the newly active screen
      for(ScreenWindow* window : qAsConst(_windows))
          window->setScreen(_currentScreen);
+     checkScreenInUse();
   }
 }
 

lib/Emulation.h

@@ -433,6 +433,12 @@ public slots:
    */
   void flowControlKeyPressed(bool suspendKeyPressed);
 
+  /**
+   * Emitted when the active screen is switched, to indicate whether the primary
+   * screen is in use.
+   */
+  void primaryScreenInUse(bool use);
+
   /**
    * Emitted when the cursor shape or its blinking state is changed via
    * DECSCUSR sequences.
@@ -497,6 +503,9 @@ protected slots:
    */
   void bufferedUpdate();
 
+  // used to emit the primaryScreenInUse(bool) signal
+  void checkScreenInUse();
+
 private slots:
 
   // triggered by timer, causes the emulation to send an updated screen image to each

lib/Session.cpp

@@ -71,6 +71,7 @@ Session::Session(QObject* parent) :
 //   , _zmodemProc(0)
 //   , _zmodemProgress(0)
         , _hasDarkBackground(false)
+      , _isPrimaryScreen(true)
 {
     //prepare DBus communication
 //    new SessionAdaptor(this);
@@ -94,7 +95,8 @@ Session::Session(QObject* parent) :
              this, SIGNAL( changeTabTextColorRequest( int ) ) );
     connect( _emulation, SIGNAL(profileChangeCommandReceived(const QString &)),
              this, SIGNAL( profileChangeCommandReceived(const QString &)) );
-
+    connect(_emulation, &Konsole::Emulation::primaryScreenInUse,
+            this, &Session::onPrimaryScreenInUse);
     connect(_emulation, SIGNAL(imageResizeRequest(QSize)),
             this, SLOT(onEmulationSizeChange(QSize)));
     connect(_emulation, SIGNAL(imageSizeChanged(int, int)),
@@ -204,6 +206,8 @@ void Session::addView(TerminalDisplay * widget)
                       SLOT(viewDestroyed(QObject *)) );
 //slot for close
     QObject::connect(this, SIGNAL(finished()), widget, SLOT(close()));
+//slot for primaryScreen
+    QObject::connect(this, &Session::primaryScreenInUse, widget, &TerminalDisplay::usingPrimaryScreen);
 
 }
 
@@ -448,6 +452,11 @@ void Session::monitorTimerDone()
     _notifiedActivity=false;
 }
 
+bool Session::isPrimaryScreen()
+{
+    return _isPrimaryScreen;
+}
+
 void Session::activityStateSet(int state)
 {
     if (state==NOTIFYBELL) {
@@ -485,6 +494,12 @@ void Session::onEmulationSizeChange(QSize size)
     setSize(size);
 }
 
+void Session::onPrimaryScreenInUse(bool use)
+{
+    _isPrimaryScreen = use;
+    emit primaryScreenInUse(use);
+}
+
 void Session::updateTerminalSize()
 {
     QListIterator<TerminalDisplay *> viewIter(_views);

lib/Session.h

@@ -375,6 +375,10 @@ class Session : public QObject {
      */
     int getPtySlaveFd() const;
 
+    // Returns true if the current screen is the secondary/alternate one
+    // or false if it's the primary/normal buffer
+    bool isPrimaryScreen();
+
 public slots:
 
     /**
@@ -480,6 +484,15 @@ public slots:
      */
     void flowControlEnabledChanged(bool enabled);
 
+    /**
+     * Emitted when the active screen is switched, to indicate whether the primary
+     * screen is in use.
+     *
+     * This signal serves as a relayer of Emulation::priamyScreenInUse(bool),
+     * making it usable for higher level component.
+     */
+    void primaryScreenInUse(bool use);
+
     /**
      * Broker for Emulation::cursorChanged() signal
      */
@@ -509,6 +522,9 @@ private slots:
 //  void zmodemRcvBlock(const char *data, int len);
 //  void zmodemFinished();
 
+    // Relays the signal from Emulation and sets _isPrimaryScreen
+    void onPrimaryScreenInUse(bool use);
+
 private:
 
     void updateTerminalSize();
@@ -570,6 +586,7 @@ private slots:
 
     int ptySlaveFd;
 
+    bool _isPrimaryScreen;
 };
 
 /**

lib/TerminalDisplay.cpp

@@ -334,6 +334,7 @@ TerminalDisplay::TerminalDisplay(QWidget *parent)
 ,_terminalSizeStartup(true)
 ,_bidiEnabled(false)
 ,_mouseMarks(false)
+,_isPrimaryScreen(true)
 ,_disabledBracketedPasteMode(false)
 ,_actSel(0)
 ,_wordSelectionMode(false)
@@ -2554,17 +2555,13 @@ void TerminalDisplay::wheelEvent( QWheelEvent* ev )
   if (ev->angleDelta().y() == 0)
     return;
 
-  // if the terminal program is not interested mouse events
-  // then send the event to the scrollbar if the slider has room to move
-  // or otherwise send simulated up / down key presses to the terminal program
-  // for the benefit of programs such as 'less'
-  if ( _mouseMarks )
-  {
-    bool canScroll = _scrollBar->maximum() > 0;
-      if (canScroll)
-        _scrollBar->event(ev);
-    else
+    if (_mouseMarks && _scrollBar->maximum() > 0)
     {
+        // If the program running in the terminal is not interested in
+        // Mouse events, send the event to the scrollbar if the slider
+        // has room to move
+        _scrollBar->event(ev);
+    } else if(_mouseMarks && !_isPrimaryScreen) {
         // assume that each Up / Down key event will cause the terminal application
         // to scroll by one line.
         //
@@ -2581,21 +2578,18 @@ void TerminalDisplay::wheelEvent( QWheelEvent* ev )
 
         for (int i=0;i<linesToScroll;i++)
             emit keyPressedSignal(&keyScrollEvent, false);
-    }
-  }
-  else
-  {
-    // terminal program wants notification of mouse activity
+    } else if(!_mouseMarks) {
+        // terminal program wants notification of mouse activity
 
-    int charLine;
-    int charColumn;
-    getCharacterPosition( ev->position() , charLine , charColumn );
+        int charLine;
+        int charColumn;
+        getCharacterPosition( ev->pos() , charLine , charColumn );
 
-    emit mouseSignal( ev->angleDelta().y() > 0 ? 4 : 5,
-                      charColumn + 1,
-                      charLine + 1 +_scrollBar->value() -_scrollBar->maximum() ,
-                      0);
-  }
+        emit mouseSignal( ev->angleDelta().y() > 0 ? 4 : 5,
+                          charColumn + 1,
+                          charLine + 1 +_scrollBar->value() -_scrollBar->maximum() ,
+                          0);
+    }
 }
 
 void TerminalDisplay::tripleClickTimeout()
@@ -2700,6 +2694,11 @@ bool TerminalDisplay::usesMouse() const
     return _mouseMarks;
 }
 
+void TerminalDisplay::usingPrimaryScreen(bool use)
+{
+    _isPrimaryScreen = use;
+}
+
 void TerminalDisplay::setBracketedPasteMode(bool on)
 {
     _bracketedPasteMode = on;

lib/TerminalDisplay.h

@@ -505,6 +505,15 @@ public slots:
     /** See setUsesMouse() */
     bool usesMouse() const;
 
+    /**
+     * Sets _isPrimaryScreen depending on which screen is currently in
+     * use, primary or alternate
+     *
+     * @param use Set to @c true if the primary screen is in use or to
+     * @c false otherwise (i.e. the alternate screen is in use)
+     */
+    void usingPrimaryScreen(bool use);
+
     void setBracketedPasteMode(bool bracketedPasteMode);
     bool bracketedPasteMode() const;
 
@@ -767,6 +776,7 @@ private slots:
     bool _terminalSizeStartup;
     bool _bidiEnabled;
     bool _mouseMarks;
+    bool _isPrimaryScreen;
     bool _bracketedPasteMode;
     bool _disabledBracketedPasteMode;