function getColumnFullWidth() {
        
        if (!options.paginationInfo || isVerticalWritingMode())
        {
            return $iframe.width();
        }
        
        return options.paginationInfo.columnWidth + options.paginationInfo.columnGap;
    }
@private
Retrieves _current_ full width of a column (including its gap)

@returns {number} Full width of a column in pixels