Making a screen shot (Windows has trouble with big resolutions)

Problem/Question/Abstract:

I just want to give you an example of making a screen shot in "tiles" and pasting the results yourself.

Answer:

Sometimes you want to take a screen shot, however often Windows has trouble with big data amounts and becomes very slow. The simple solution is to make many small screen shots and paste the result together. It's not light speed, however often faster than taking the whole screen at once.

const
  cTileSize = 50;

function TForm1.GetScreenShot: TBitmap;
var
  Locked: Boolean;
  X, Y, XS, YS: Integer;
  Canvas: TCanvas;
  R: TRect;
begin
  Result := TBitmap.Create;
  Result.Width := Screen.Width;
  Result.Height := Screen.Height;
  Canvas := TCanvas.Create;
  Canvas.Handle := GetDC(0);
  Locked := Canvas.TryLock;
  try
    XS := Pred(Screen.Width div cTileSize);
    if Screen.Width mod cTileSize > 0 then
      Inc(XS);
    YS := Pred(Screen.Height div cTileSize);
    if Screen.Height mod cTileSize > 0 then
      Inc(YS);
    for X := 0 to XS do
      for Y := 0 to YS do
      begin
        R := Rect(
          X * cTileSize, Y * cTileSize, Succ(X) * cTileSize,
          Succ(Y) * cTileSize
          );
        Result.Canvas.CopyRect(R, Canvas, R);
      end;
  finally
    if Locked then
      Canvas.Unlock;
    ReleaseDC(0, Canvas.Handle);
    Canvas.Free;
  end;
end;