Allow for showing line numbers

As with semantic hints, the line numbers may be displayed always, never
or when URL hints are shown.

src/ViewManager.cpp

@@ -294,6 +294,12 @@ void ViewManager::setupActions()
     connect(action, &QAction::triggered, this, &ViewManager::toggleSemanticHints);
     _viewContainer->addAction(action);
 
+    action = new QAction(i18nc("@action Shortcut entry", "Toggle line numbers display"), this);
+    collection->addAction(QStringLiteral("toggle-line-numbers"), action);
+    collection->setDefaultShortcut(action, Qt::CTRL | Qt::ALT | Qt::Key_Backslash);
+    connect(action, &QAction::triggered, this, &ViewManager::toggleLineNumbers);
+    _viewContainer->addAction(action);
+
     action = new QAction(this);
     action->setText(i18nc("@action:inmenu", "Equal size to all views"));
     collection->setDefaultShortcut(action, Konsole::ACCEL | Qt::SHIFT | Qt::Key_Backslash);
@@ -522,6 +528,22 @@ void ViewManager::toggleSemanticHints()
     activeTerminalDisplay->update();
 }
 
+void ViewManager::toggleLineNumbers()
+{
+    int currentSessionId = currentSession();
+    Q_ASSERT(currentSessionId >= 0);
+    Session *activeSession = SessionManager::instance()->idToSession(currentSessionId);
+    Q_ASSERT(activeSession);
+    auto profile = SessionManager::instance()->sessionProfile(activeSession);
+
+    profile->setProperty(Profile::LineNumbers, (profile->lineNumbers() + 1) % 3);
+
+    auto activeTerminalDisplay = _viewContainer->activeViewSplitter()->activeTerminalDisplay();
+    const char *names[3] = {"Never", "Sometimes", "Always"};
+    activeTerminalDisplay->showNotification(i18n("Line numbers ") + i18n(names[profile->lineNumbers()]));
+    activeTerminalDisplay->update();
+}
+
 QHash<TerminalDisplay *, Session *> ViewManager::forgetAll(ViewSplitter *splitter)
 {
     splitter->setParent(nullptr);

src/ViewManager.h

@@ -404,6 +404,8 @@ private Q_SLOTS:
 
     void toggleSemanticHints();
 
+    void toggleLineNumbers();
+
 private:
     Q_DISABLE_COPY(ViewManager)
 

src/profile/Profile.cpp

@@ -120,6 +120,7 @@ const std::vector<Profile::PropertyInfo> Profile::DefaultProperties = {
     {VerticalLine, "VerticalLine", TERMINAL_GROUP, false},
     {VerticalLineAtChar, "VerticalLineAtChar", TERMINAL_GROUP, 80},
     {PeekPrimaryKeySequence, "PeekPrimaryKeySequence", TERMINAL_GROUP, QString()},
+    {LineNumbers, "LineNumbers", TERMINAL_GROUP, 0},
 
     // Cursor
     {UseCustomCursorColor, "UseCustomCursorColor", CURSOR_GROUP, false},

src/profile/Profile.h

@@ -374,6 +374,10 @@ public:
         /** (QFont) Emoji font override
          */
         EmojiFont,
+        /** When to show line numbers.
+         * 0 for Never, 1 when showing URL hints, 2 for always
+         */
+        LineNumbers,
     };
 
     Q_ENUM(Property)
@@ -805,6 +809,11 @@ public:
         return property<int>(Profile::SemanticHints);
     }
 
+    int lineNumbers() const
+    {
+        return property<int>(Profile::LineNumbers);
+    }
+
     bool semanticUpDown() const
     {
         return property<bool>(Profile::SemanticUpDown);

src/terminalDisplay/TerminalPainter.cpp

@@ -78,6 +78,7 @@ void TerminalPainter::drawContents(Character *image,
     auto currentProfile = SessionManager::instance()->sessionProfile(m_parentDisplay->session());
     const bool invertedRendition = currentProfile ? currentProfile->property<bool>(Profile::InvertSelectionColors) : false;
     const Enum::Hints semanticHints = currentProfile ? static_cast<Enum::Hints>(currentProfile->semanticHints()) : Enum::HintsNever;
+    const Enum::Hints lineNumbers = currentProfile ? static_cast<Enum::Hints>(currentProfile->lineNumbers()) : Enum::HintsNever;
 
     QVector<uint> univec;
     univec.reserve(m_parentDisplay->usedColumns());
@@ -250,6 +251,16 @@ void TerminalPainter::drawContents(Character *image,
             paint.setPen(pen);
             paint.drawLine(leftPadding, textY, m_parentDisplay->contentRect().right(), textY);
         }
+        if ((lineNumbers == Enum::HintsURL && m_parentDisplay->filterChain()->showUrlHint()) || lineNumbers == Enum::HintsAlways) {
+            QRect rect(m_parentDisplay->contentRect().right() - 4 * fontWidth, textY, m_parentDisplay->contentRect().right(), textY + fontHeight);
+            QPen pen(QColor(0xC00000));
+            paint.setPen(pen);
+            QFont currentFont = paint.font();
+            currentFont.setWeight(normalWeight);
+            currentFont.setItalic(false);
+            paint.setFont(currentFont);
+            paint.drawText(rect, Qt::AlignLeft, QString::number(y + m_parentDisplay->screenWindow()->currentLine()));
+        }
 
         if (doubleHeightLinePair) {
             y++;