How to control scrolling in TextArea

nomionz

Hi
I want to use TextArea to display colored logs. I know that ListView is more efficient for this task, but for my use case TextArea fits (and I like the colored borders when focused). I wrapped the TextArea in a ScrollView, as the documentation suggests. I color and add text through a C++ class that implements QSyntaxHighlighting and inserts text through QTextCursor. So I don't use the TextArea append function or the +=. The problem is that every time I add new text, ScrollView scrolls to the end automatically, but I want to scroll to the top and look at the text that was added earlier, and when I'm done, I want to enable auto-scrolling again by just scrolling to the end or perhaps by using a button. I don't see a clear way to achieve this behavior. Many thanks in advance.

the qml file code is

ScrollView {
  id: textAreaView
  Layout.fillHeight: true
  Layout.fillWidth: true
  wheelEnabled: true
  background: Rectangle {
    color: Material.background
    border.color: textAreaView.focus ? Material.accent : "#bdbebf"
    border.width: 2
  }

  TextArea {
    id: textArea
    height: _root.height - textInput.height
    readOnly: true
    textFormat: TextEdit.PlainText
    width: _root.width
    wrapMode: Text.Wrap

    Component.onCompleted: {
       highlighter.onCompleted()
    }
                
    Connections {
      target: logger
      onDeviceLogReceived: function (msg) { 
         highlighter.append(msg);
       }
     }
                
    HighlighterComponent {
       id: highlighter
    }
}

the c++ highlighter function

void Highlighter::append(const QString& text) {
    QTextCursor cursor(doc);
    cursor.movePosition(QTextCursor::End);

    static QRegularExpression regex("^\[\\d+:\\d+:\\d+\\.\\d+,\\d+\] <(dbg|inf|wrn|err)>");
    QRegularExpressionMatch match = regex.match(text);

    if (match.hasMatch()) {
        QString tag = match.captured(1);
        MessageType type = getMessageType(tag);
        QTextCharFormat format = highlightingRules.value(type);

        cursor.insertText(match.captured(0), format);
        cursor.insertText(text.mid(match.capturedEnd()), defaultFormat);
    } else {
        cursor.insertText(text, defaultFormat);
    }
    cursor.insertText("\n", defaultFormat);
}