/// <summary>
/// CheckForLineScroll() looks at the console's top line and tries to determine if any lines have vanished as the console has scrolled up. It is an imperfect
/// check in that it can be fooled, and a more thorough console validation would be required for certainty, but it is good for identifying some "delta" situations
/// where the console can be re-synced simply by removing some lines at the top.
/// </summary>
/// <param name="Stale">Set to true if CheckForLineScroll() has determined that the console is sufficiently out-of-sync with the tracker that the
/// line scroll check cannot be performed reliably.</param>
/// <returns>The number of lines which have vanished from the top of the console.</returns>
public int CheckForLineScroll(out bool Stale)
{
if (PendingReload)
{
PendingReload = false; Stale = true; return(0);
} // Force first read to always give Stale so we use GetWholeConsole().
ConsoleApi.CONSOLE_SCREEN_BUFFER_INFO info = Console.GetInfo();
if (info.dwCursorPosition.Y < LastCursorPosition.Y)
{
Stale = true; return(0);
}
Stale = false;
ConsoleApi.CHAR_INFO[] LineBuffer = new ConsoleApi.CHAR_INFO[info.dwSize.X];
COORD LineBufferSize = new COORD();
LineBufferSize.X = info.dwSize.X;
LineBufferSize.Y = 1;
COORD Origin = new COORD();
Origin.X = Origin.Y = 0;
ConsoleApi.SMALL_RECT ConsoleRect = new ConsoleApi.SMALL_RECT();
ConsoleRect.Left = 0;
ConsoleRect.Right = (short)(info.dwSize.X - 1);
ConsoleRect.Top = (short)0;
ConsoleRect.Bottom = (short)0;
// Read the top of the console to compare against our current state
Console.ReadOutput(LineBuffer, LineBufferSize, Origin, ref ConsoleRect);
StringBuilder sbLine = new StringBuilder();
for (int xx = 0; xx < info.dwSize.X; xx++)
{
sbLine.Append(LineBuffer[xx].UnicodeChar);
}
string FirstLine = sbLine.ToString().TrimEnd();
sbLine.Clear();
if (Lines.Count > 0 && Lines[0] != FirstLine)
{
for (int yy = 0; yy < Lines.Count; yy++)
{
if (Lines[yy] == FirstLine)
{
Lines.RemoveRange(0, yy);
return(yy);
}
}
Stale = true;
return(0);
}
return(0);
}