void InvalidateLines(int xPos, int lineBegin, int lineEnd)
{
lineBegin = Math.Max(Document.GetVisibleLine(lineBegin), FirstPhysicalLine);
lineEnd = Math.Min(Document.GetVisibleLine(lineEnd), FirstPhysicalLine + textView.VisibleLineCount);
int y = Math.Max( 0, (int)(lineBegin * textView.FontHeight));
int height = Math.Min(textView.DrawingPosition.Height, (int)((1 + lineEnd - lineBegin) * (textView.FontHeight + 1)));
Rectangle r = new Rectangle(0,
y - 1 - this.virtualTop.Y,
Width,
height + 3);
Invalidate(r);
}
#endregion
