BASS - Wykres natężenia dźwięku

type TFFT = array [0..512] of DWORD;

type
  TGraph = class(TObject)
    Channel : DWORD;
    XPos, YPos : integer;
    Buffer : TFFT;
    Paint : TImage;
    Size : integer;
    Timer : TTimer;

    constructor Create(Canv : TImage; Ps : TPenStyle; Pc : TColor; Psz, Gw : integer);
    procedure Draw(Sender: TObject);
    procedure Start(Chan : DWORD);
    procedure Stop();
end;


//.............................................

constructor TGraph.Create(Canv : TImage; Ps : TPenStyle; Pc : TColor; Psz, Gw : integer);
begin
  Paint := Canv;
  with Paint.Canvas.Pen do
  begin
    Style := Ps;
    Color := Pc;
    Width := Psz;
  end;
  Size := Gw;
  Timer := TTimer.Create(nil);
  Timer.Enabled := false;
  Timer.OnTimer := Draw;
  Timer.Interval := 33;
end;

procedure TGraph.Draw(Sender: TObject);
var
  i, n : integer;
begin
if (BASS_ChannelIsActive(Channel) > 0) then
begin
  Application.ProcessMessages;
  YPos := BASS_ChannelGetLevel(Channel) div 3000000;
  for i := 0 to size-1 do
    for n := 0 to Paint.Height do
      Paint.Canvas.Pixels[XPos+i, n] := clWhite;
  Paint.Canvas.LineTo(XPos, Paint.Height - YPos);
  if XPos >= Paint.Width then
  begin
    XPos := 0;
    Paint.Canvas.MoveTo(0,0);
  end
  else
    XPos := XPos + size;
end;
end;

procedure TGraph.Start(Chan : DWORD);
begin
  Timer.Enabled := true;
  Channel := Chan;
end;

procedure TGraph.Stop();
begin
  Timer.Enabled := false;
end;

Użycie:

var
  Gr : TGraph;
//-----
Gr := TGraph.Create(Image1, psSolid, clBlack, 1, 5);

//BASS_StreamCreateFile(...)
//BASS_ChannelPlay(...)

 Gr.Start(Channel);

 //aby zakonczyc rysowanie: Gr.Stop;