Sources
Delphi Russian Knowledge Base
DRKB - это самая большая и удобная в использовании база знаний по Дельфи в рунете, составленная Виталием Невзоровым

Show text progressively as typed with a typewriter (horizontal/vertical)

01.01.2007
{
 
To make this code to work you would need 2 images,
 one
for the horizontal- and another for the vertical text.
}
 
// VerticalTypewriter ( <Text>, <Image to write to>, <Time to delay between every chars> )
procedure
VerticalTypewriter(text: string; image: timage; delay: integer);
var
 x
,y,i: integer;
begin
 image
.Canvas.Refresh;
 application
.ProcessMessages;
 y
:= 1;
 
 
for i := 1 to length(text) do begin
  application
.ProcessMessages;
  y
:= y+image.Canvas.TextHeight(text[i]);
  x
:= image.width div 2 - (image.Canvas.TextWidth(text[i]) div 2);
  image
.Canvas.TextOut(x,y,text[i]);
  sleep
(delay);
 
end;
 
end;
 
// Horizontal Typewriter ( <Text>, <Image to write to>, <Time to delay between every chars>, <Space between chars>)
procedure
HorizontalTypewriter(text: string; image: timage; delay, space: integer);
var
 x
,y,i: integer;
begin
 image
.Canvas.Refresh;
 application
.ProcessMessages;
 x
:= 1;
 
 
for i := 1 to length(text) do begin
  application
.ProcessMessages;
  y
:= image.Picture.Height div 2 - (image.Canvas.TextHeight(text[i]) div 2);
  x
:= x+image.Canvas.TextWidth(text[i])+space;
  image
.Canvas.TextOut(x,y,text[i]);
  sleep
(delay);
 
end;
 
end;
 
 
// Sample calls:
procedure TForm1
.Button1Click(Sender: TObject);
begin
 
//                  <text>          <image>  <delay>
 
VerticalTypewriter('HELLO BIG-X',   image1,  100     );
end;
 
procedure TForm1
.Button2Click(Sender: TObject);
begin
 
//                    <text>         <image>  <delay>  <space>
 
HorizontalTypewriter('Hello Big-X',  image2,  100,     1       );
end;

Взято с сайта https://www.swissdelphicenter.ch/en/tipsindex.php