How to print a string grid in the center of a page?

So I want to print a string grid in the middle/center of another printed page that already has a printed/header and footer, but I'm not sure how to print the string grid in the middle/center of the page? Is there anything in the code below that I can change to do that? Or do I have to do something else completely?

Thanks in advance for all the help!

Example of the type of page I have to print on (In the open part of the page):

Code I've used for one of the other buttons that also prints:

procedure PrintGrid(sGrid: TStringGrid; sTitle: string);
var
  X1, X2: Integer;
  Y1, Y2: Integer;
  TmpI: Integer;
  F: Integer;
  TR: TRect;
begin
  Printer.Title := sTitle;
  Printer.BeginDoc;
  Printer.Canvas.Pen.Color  := 0;
  Printer.Canvas.Font.Name  := 'Times New Roman';
  Printer.Canvas.Font.Size  := 12;
  Printer.Canvas.Font.Style := [fsBold, fsUnderline];
  Printer.Canvas.TextOut(0, 100, Printer.Title);
  for F := 1 to sGrid.ColCount - 1 do 
  begin
    X1 := 0;
    for TmpI := 1 to (F - 1) do
      X1 := X1 + 5 * (sGrid.ColWidths[TmpI]);
    Y1 := 300;
    X2 := 0;
    for TmpI := 1 to F do
      X2 := X2 + 5 * (sGrid.ColWidths[TmpI]);
    Y2 := 450;
    TR := Rect(X1, Y1, X2 - 30, Y2);
    Printer.Canvas.Font.Style := [fsBold];
    Printer.Canvas.Font.Size := 7;
    Printer.Canvas.TextRect(TR, X1 + 50, 350, sGrid.Cells[F, 0]);
    Printer.Canvas.Font.Style := [];
    for TmpI := 1 to sGrid.RowCount - 1 do 
    begin
      Y1 := 150 * TmpI + 300;
      Y2 := 150 * (TmpI + 1) + 300;
      TR := Rect(X1, Y1, X2 - 30, Y2);
      Printer.Canvas.TextRect(TR, X1 + 50, Y1 + 50, sGrid.Cells[F, TmpI]);
    end;
  end;
  Printer.EndDoc;
end;

Kind Regards PrimeBeat

You can get printer width and height in pixel (Printer.PageWidth and Printer.PageHeight). You can get text with and height using Printer.Canvas.TextExtent. You have your grid so you know the number of rows and column. The rest is some easy computing. You can adapt the font size so that the grid fits in the given space.