/// <summary>
/// Gets the start visual column from the specified text line.
/// </summary>
public int GetTextLineVisualStartColumn(TextLine textLine)
{
if (!TextLines.Contains(textLine))
{
throw new ArgumentException("textLine is not a line in this VisualLine");
}
return(TextLines.TakeWhile(tl => tl != textLine).Sum(tl => tl.Length));
}