hasContent method
Checks if there is any content in history or text boxes for the current page.
Implementation
bool hasContent({bool isRedo = false}) {
return isRedo
? _undoStack[_currentPage]?.isNotEmpty ==
true // Check redo stack.
: _history[_currentPage]?.isNotEmpty == true ||
_textBoxes[_currentPage]?.isNotEmpty ==
true; // Check history or text boxes.
}