⤷ Get color using RGB function

Use RGB function for getting different kinds of colors.
Put three ScrollBars and Label on your form and you will see color and parameters for RGB function of this color.
Set onChange event for the ScrollBar2 and ScrollBar3 to ScrollBar1Change, so changing of each ScrollBar will be processed.

procedure TForm1.ScrollBar1Change(Sender: TObject);
begin
  Form1.Color:=RGB(
    ScrollBar1.Position,
    ScrollBar2.Position,
    ScrollBar3.Position);
  Label1.Font.Color:=RGB(
    255-ScrollBar1.Position,
    255-ScrollBar2.Position,
    255-ScrollBar3.Position);
  Label1.Caption:='RGB('+
    IntToStr(ScrollBar1.Position)+','+
    IntToStr(ScrollBar2.Position)+','+
    IntToStr(ScrollBar3.Position)+')';
end;
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