Editor: transform the line column label into button

Having a button instead of a labal makes it more obvious that there is
an action triggered when clicking the label.

Also fix the flickering introduced by
f0bb7e8bfa by saving the maximum width of
the sizeHint. Since the width can get big if we have a selection we do
not save the size in that case to avoid blocking the width when the
selection is removed again.

Change-Id: If8210ecbabb8c6449c4f88652fbed99f8526057d
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/texteditor/texteditor.cpp

@@ -150,16 +150,16 @@ using ListTransformationMethod = void(QStringList &);
 
 static constexpr char dropProperty[] = "dropProp";
 
-class LineColumnLabel : public FixedSizeClickLabel
+class LineColumnButton : public QToolButton
 {
     Q_OBJECT
 public:
-    LineColumnLabel(TextEditorWidget *parent)
-        : FixedSizeClickLabel(parent)
+    LineColumnButton(TextEditorWidget *parent)
+        : QToolButton(parent)
         , m_editor(parent)
     {
-        connect(m_editor, &QPlainTextEdit::cursorPositionChanged, this, &LineColumnLabel::update);
-        connect(this, &FixedSizeClickLabel::clicked, ActionManager::instance(), [this] {
+        connect(m_editor, &QPlainTextEdit::cursorPositionChanged, this, &LineColumnButton::update);
+        connect(this, &QToolButton::pressed, ActionManager::instance(), [this] {
             emit m_editor->activateEditor(EditorManager::IgnoreNavigationHistory);
             QMetaObject::invokeMethod(ActionManager::instance(), [] {
                 if (Command *cmd = ActionManager::command(Core::Constants::GOTO)) {
@@ -198,7 +198,7 @@ private:
     bool event(QEvent *event) override
     {
         if (event->type() != QEvent::ToolTip)
-            return FixedSizeClickLabel::event(event);
+            return QToolButton::event(event);
 
         QString tooltipText = "<table cellpadding='2'>\n";
 
@@ -243,6 +243,19 @@ private:
         return true;
     }
 
+    QSize sizeHint() const override
+    {
+        const QSize size = QToolButton::sizeHint();
+        auto wider = [](const QSize &left, const QSize &right) {
+            return left.width() < right.width();
+        };
+        if (m_editor->multiTextCursor().hasSelection())
+            return std::max(m_maxSize, size, wider); // do not save the size if we have a selection
+        m_maxSize = std::max(m_maxSize, size, wider);
+        return m_maxSize;
+    }
+
+    mutable QSize m_maxSize;
     TextEditorWidget *m_editor;
 };
 
@@ -714,7 +727,7 @@ public:
     QWidget *m_stretchWidget = nullptr;
     QAction *m_stretchAction = nullptr;
     QAction *m_toolbarOutlineAction = nullptr;
-    LineColumnLabel *m_cursorPositionLabel = nullptr;
+    LineColumnButton *m_cursorPositionLabel = nullptr;
     FixedSizeClickLabel *m_fileEncodingLabel = nullptr;
     QAction *m_fileEncodingLabelAction = nullptr;
     BaseTextFind *m_find = nullptr;
@@ -1023,8 +1036,8 @@ TextEditorWidgetPrivate::TextEditorWidgetPrivate(TextEditorWidget *parent)
     m_stretchAction = m_toolBar->addWidget(m_stretchWidget);
     m_toolBarWidget->layout()->addWidget(m_toolBar);
 
-    m_cursorPositionLabel = new LineColumnLabel(q);
     const int spacing = q->style()->pixelMetric(QStyle::PM_LayoutHorizontalSpacing) / 2;
+    m_cursorPositionLabel = new LineColumnButton(q);
     m_cursorPositionLabel->setContentsMargins(spacing, 0, spacing, 0);
     m_toolBarWidget->layout()->addWidget(m_cursorPositionLabel);