private VisualTextLine CutStandardLine(VisualTextLine line, int startIndex, int count) {
var contents = line.GetStringContents()[0];
var newText = string.Empty;
if (startIndex + count == line.Length) {
newText = contents.Substring(startIndex);
} else {
newText = contents.Substring(startIndex, count - startIndex);
}
return VisualTextLine.Create(newText, line.Index);
}
