type
  TMyAnimation = class(TThread)
  private
    FBitmap: TBitmap;
    FTargetCanvas: TCanvas;
    procedure DrawFrame;
  protected
    procedure Execute; override;
  public
    constructor Create(aCanvas: TCanvas);
    destructor Destroy; override;
  end;

implementation

constructor TMyAnimation.Create(aCanvas: TCanvas);
begin
  inherited Create(false);
  FTargetCanvas := aCanvas;
  FBitmap := TBitmap.Create;
end;

destructor TMyAnimation.Destroy;
begin
  FBitmap.Free;
end;

procedure TMyAnimation.DrawFrame;
begin
  FTargetCanvas.Draw(FBitmap.Canvas, ... ...);
end;

procedure TMyAnimation.Execute;
var
  loopBeginTickCount: Int64;
const
  MS_PER_FRAME = 50;
begin
  repeat
    loopBeginTickCount := GetTickCount;
    // FBitmap mit neuem Frame bestücken, was auch immer das ist
    Synchronize(DrawFrame);
    Sleep(Max(MS_PER_FRAME - (GetTickCount-loopBeginTickCount), 1));
  until Terminated;
end;