procedure TForm1.FormCreate(Sender: TObject); 
var x: integer; 
begin 
  // --------- nur zum Testen ----------- 
  Richedit1.clear; 
  Richedit1.ScrollBars := ssBoth; 
  for x := 1 to 9 do 
    Richedit1.lines.add('Zeile ' 
      + inttostr(x)); 
  //---------------------------------------------------- 
end; 
 
procedure FaerbeZeile(RE: TCustomRichedit; Zeile: Integer; Farbe: TColor; 
  Style: TFontStyles); 
var zl: Integer; 
begin 
  zl := pred(Zeile); 
  with RE do begin 
    SelStart := Perform(EM_LINEINDEX, zl, 0); 
    SelLength := Length(Lines[zl]); 
    SelAttributes.Color := Farbe; 
    SelAttributes.Style := Style; 
    SelLength := 0; 
  end; 
end; 
 
// Beispielaufruf 
 
procedure TForm1.Button1Click(Sender: TObject); 
begin 
  FaerbeZeile(Richedit1, 2, clBlue, [FsBold, fsItalic]); 
  FaerbeZeile(Richedit1, 6, clFuchsia, [fsBold]); 
end;