Two TrackBar mirror - delphi

Question

I would like to know how to make my second trackbar.position mirror in the opposite direction of trackbar1.position.
eg.
Range from 1 to 100.
So When TrackBar1.Position := 2, then trackbar2.Position := 99
Regardless of which way the trackbars goes, I would like to mirror in the opposite direction.
Heres my code so far: (not interested in using keys to do this), just mouse interaction.
Direction : string;
Skip : boolean;
procedure TForm1.TrackBar1Change(Sender: TObject);
begin
if TrackBar1.Position = TrackBar2.Position then
begin
if Direction = 'up' then TrackBar2.Position := TrackBar2.Position + 1;
if Direction = 'down' then TrackBar2.Position := TrackBar2.Position - 1;
skip := true;
end;
if TrackBar1.Position < TrackBar2.Position then
begin
if skip = false then
begin
TrackBar2.Position := TrackBar2.Position - 1;
Direction := 'down';
end;
end
else
begin
if skip = false then
begin
TrackBar2.Position := TrackBar2.Position + 1;
Direction := 'up';
end;
end;
end;
Im probably overdoing this. Maybe there is a simpler way. I prefer the simpler way.
Thanks,
Ben

Answer 1

The 2 trackbars OnChange events are linked to this code:
procedure TForm1.TrackBarChange(Sender: TObject);
var
tbSource, tbTarget: TTrackBar;
begin
if Sender = TrackBar1 then // Check the Trackbar which triggers the event
begin
tbSource := TrackBar1;
tbTarget := TrackBar2;
end
else
begin
tbSource := TrackBar2;
tbTarget := TrackBar1;
end;
tbTarget.OnChange := nil; // disable the event on the other trackbar
tbTarget.Position := tbSource.Max + tbSource.Min - tbSource.Position; // set the position on the other trackbar
tbTarget.OnChange := TrackBarChange; // define the event back to the other trackbar
// Call a function or whatever after this line if you need to do something when it changes
// lbl1.Caption := IntToStr(TrackBar1.Position);
// lbl2.Caption := IntToStr(TrackBar2.Position);
end;
 
Alternative start (suggested by Ken White and comments from me ;o)):
procedure TForm1.TrackBarChange(Sender: TObject);
var
tbSource, tbTarget: TTrackBar;
begin
// if Sender is TTrackBar then // is it called 'from' a trackbar?
// begin
tbSource := TTrackBar(Sender); // Set the source
if tbSource = TrackBar1 then // Check the Trackbar which triggers the event
tbTarget := TrackBar2
else
tbTarget := TrackBar1;
tbTarget.OnChange := nil; // disable the event on the other trackbar
tbTarget.Position := tbSource.Max + tbSource.Min - tbSource.Position; // set the position on the other trackbar
tbTarget.OnChange := TrackBarChange; // define the event back to the other trackbar
// Call a function or whatever after this line if you need to do something when it changes
// lbl1.Caption := IntToStr(TrackBar1.Position);
// lbl2.Caption := IntToStr(TrackBar2.Position);
// end;
end;