Array-Eigenschaft als Parameter

[Blup]

Man könnte mit einem Adapter arbeiten. Auch andere Informationen wie Höhe, Breite, Pixelformat lassen sich mit einbeziehen.

Delphi-Quellcode:

unit ScanLineAdapter;

interface

type
  IScanLineAdapter = interface(IInterface)
    ['{A19606EB-4B25-4862-86D5-ED26E7F07F8C}']
    function GetScanLine(AIndex: Integer): Pointer;
  end;

  TScanLineAdapter = class(TInterfacedObject, IScanLineAdapter)
  protected
    function GetScanLine(AIndex: Integer): Pointer; virtual; abstract;
  end;

  TBitmapScanLineAdapter = class(TScanLineAdapter)
  private
    FItem: TBitmap;
  protected
    function GetScanLine(AIndex: Integer): Pointer; override;
  public
    constructor Create(AItem: TBitmap);
  end;

  TPngImageScanLineAdapter = class(TScanLineAdapter)
  private
    FItem: TPngImage;
  protected
    function GetScanLine(AIndex: Integer): Pointer; override;
  public
    constructor Create(AItem: TPngImage);
  end;

  TPngImageAlphaScanLineAdapter = class(TScanLineAdapter)
  private
    FItem: TPngImage;
  protected
    function GetScanLine(AIndex: Integer): Pointer; override;
  public
    constructor Create(AItem: TPngImage);
  end;

implementation

{ TBitmapScanLineAdapter }

constructor TBitmapScanLineAdapter.Create(AItem: TBitmap);
begin
  inherited Create;

  FItem := AItem;
end;

function TBitmapScanLineAdapter.GetScanLine(AIndex: Integer): Pointer;
begin
  Result := FItem.ScanLine[AIndex];
end;

{ TPngImageScanLineAdapter }

constructor TPngImageScanLineAdapter.Create(AItem: TPngImage);
begin
  inherited Create;

  FItem := AItem;
end;

function TPngImageScanLineAdapter.GetScanLine(AIndex: Integer): Pointer;
begin
  Result := FItem.ScanLine[AIndex];
end;

{ TPngImageAlphaScanLineAdapter }

constructor TPngImageAlphaScanLineAdapter.Create(AItem: TPngImage);
begin
  inherited Create;

  FItem := AItem;
end;

function TPngImageAlphaScanLineAdapter.GetScanLine(AIndex: Integer): Pointer;
begin
  Result := FItem.AlphaScanline[AIndex];
end;

end.

Das Interface sorgt hier für die automatische Freigabe des Adapters.

Delphi-Quellcode:

procedure TuWasMitScanline(AScanLineAdapter: IScanLineAdapter);
var
  lData: Pointer;
begin
  lData := AScanLineAdapter.GetScanLine(3);
  {...}
end;

TuWasMitScanline(TPngImageAlphaScanLineAdapter.Create(FPngImage));