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Atys

Member

Registered: 2016-04-02

Posts: 13

Non-Printable elements

Hi there,

I'm wondering if there is an option for setting some elements in the generated PDF as non-printable?

Edit: looks like layers are supported, have to find out how to set it's property and what property to what

Regards,

Last edited by Atys (2018-11-02 14:12:44)

Atys

Member

Registered: 2016-04-02

Posts: 13

Re: Non-Printable elements

Ok, I've zero knowledge about pdf and SynPDF, so do not expect much from me.
Here is a very rough implementation, main goal was to achieve it quickly, it would be nice if Arnaud would implement it _nicely_.

And here comes the beauty (Test it with "05 - Report created from code" / SynPdfLayers.dpr):

function TPdfDocument.CreateOptionalContentGroup(ParentContentGroup: TPdfOptionalContentGroup; const Title: string; Visible: boolean; PrintLayer: boolean = True): TPdfOptionalContentGroup;
var
  Dico, DicoD, DicU, DicASEntry, DicPr: TPdfDictionary;
  Arr, ArrOCGs, ArrAS: TPdfArray;
  i: integer;

  function FindParentContentGroupArray(Current: TPdfArray): TPdfArray;
  var
    i: integer;
  begin
    Result := nil;
    if Current = nil then
      exit;
    for i := 0 to Current.ItemCount - 1 do
      if Current.Items[i] = ParentContentGroup then
      begin
        if (i < Current.ItemCount - 1) and Current.Items[i + 1].InheritsFrom(TPdfArray) then
          Result := TPdfArray(Current.Items[i + 1])
        else
        begin
          Result := TPdfArray.Create(FXRef);
          Current.InsertItem(i + 1, Result);
        end;
        exit;
      end;
    for i := 0 to Current.ItemCount - 1 do
      if Current.Items[i].InheritsFrom(TPdfArray) then
      begin
        Result := FindParentContentGroupArray(TPdfArray(Current.Items[i]));
        if Result <> nil then
          exit;
      end;
  end;

begin
  if FUseOptionalContent then
  begin
    Result := TPdfOptionalContentGroup.Create(FXRef);
    FXRef.AddObject(Result);
    Result.AddItem('Type', 'OCG');
    Result.AddItemTextString('Name', Title);

    Dico := FRoot.Data.PdfDictionaryByName('OCProperties');

    if not PrintLayer then
    begin
      DicU := TPdfDictionary.Create(FXRef);
      DicPr := TPdfDictionary.Create(FXRef);
      DicPr.AddItem('PrintState', 'OFF');
      DicU.AddItem('Print', DicPr);
      Result.AddItem('Usage', DicU);
    end;

    if Dico <> nil then
    begin
      DicoD := Dico.PdfDictionaryByName('D');
      if DicoD <> nil then
      begin

        Arr := DicoD.PdfArrayByName('Order');
        if ParentContentGroup <> nil then
          Arr := FindParentContentGroupArray(Arr);
        if Arr <> nil then
          Arr.AddItem(Result);

        if not Visible then
        begin
          Arr := DicoD.PdfArrayByName('OFF');
          if Arr <> nil then
            Arr.AddItem(Result);
        end;

        if not PrintLayer then
        begin
          ArrAS := DicoD.PdfArrayByName('AS');
          if ArrAS = nil then
          begin
            ArrAS := TPdfArray.Create(FXRef);
            DicASEntry := TPdfDictionary.Create(FXRef);
            DicASEntry.AddItem('Event', 'Print');
            DicASEntry.AddItem('Category', TPdfArray.CreateNames(FXRef, ['Print']));
            ArrOCGs := TPdfArray.Create(FXRef);
            ArrOCGs.AddItem(Result);
            DicASEntry.AddItem('OCGs', ArrOCGs);
            ArrAS.AddItem(DicASEntry);
            DicoD.AddItem('AS', ArrAS);
          end
          else
          begin
            for i := 0 to ArrAS.ItemCount - 1 do
            begin
              if TPdfName(TPdfDictionaryElement(TPdfDictionary(ArrAS.Items[i]).ValueByName('Event'))).Value = 'Print' then
              begin
                ArrOCGs := TPdfArray(TPdfDictionary(ArrAS.Items[i]).ValueByName('OCGs'));
                if ArrOCGs <> nil then
                  ArrOCGs.AddItem(Result);
              end;
            end;
          end;

        end;
        Arr := Dico.PdfArrayByName('OCGs');
        if Arr <> nil then
          Arr.AddItem(Result);
      end;

    end;
  end
  else
    Result := nil;
end;

Last edited by Atys (2018-11-02 19:20:00)

Atys

Member

Registered: 2016-04-02

Posts: 13

Re: Non-Printable elements

Does not work with VCLCanvas

How to flush VCLCanvas' buffer before 'EMC'?

Last edited by Atys (2018-11-02 22:30:06)

Atys

Member

Registered: 2016-04-02

Posts: 13

Re: Non-Printable elements

Solved with GDIComment. Phew, I'm supporting myself very good. This is awesome, I'm wondering if anyone anytime implements this.

Atys

Member

Registered: 2016-04-02

Posts: 13

Re: Non-Printable elements

I've no better idea for these two methods then vclcanvas is not our class.

(Are the RawUTF8() casts okay?)

procedure TPdfDocumentGDI.VclCanvasBeginMarkedContent(Group: TPdfOptionalContentGroup);
var
  Resources, Properties: TPdfDictionary;
  ID: PDFString;
begin
  if not UseOptionalContent then
    exit;
  if Group <> nil then
  begin
    ID := 'oc' + UInt32ToPDFString(Group.ObjectNumber);
    // register Group in page resources properties
    Resources := Canvas.FPage.PdfDictionaryByName('Resources');
    if Resources <> nil then
    begin
      Properties := Resources.PdfDictionaryByName('Properties');
      if Properties = nil then
      begin
        Properties := TPdfDictionary.Create(Canvas.fDoc.FXRef);
        Resources.AddItem('Properties', Properties);
      end;
      if Properties <> nil then
        Properties.AddItem(ID, Group);
    end;
    GDICommentCustomCode(VCLCanvas.Handle, RawUTF8('/OC /' + ID + ' BDC'#10));
  end
  else
    GDICommentCustomCode(VCLCanvas.Handle, RawUTF8('/OC BMC'#10));
end;

procedure TPdfDocumentGDI.VclCanvasEndMarkedContent;
begin
  if UseOptionalContent then
    GDICommentCustomCode(VCLCanvas.Handle, RawUTF8('EMC'#10));
end;

I made it general, instead of two messages with begin/end content.

procedure GDICommentCustomCode(MetaHandle: HDC; const aCustomCode: RawUTF8);
var
  Data: RawByteString;
  d: PAnsiChar;
  L: integer;
begin // high(TPdfGDIComment)<$47 so it will never begin with GDICOMMENT_IDENTIFIER
  L := length(aCustomCode);
  SetLength(Data, L + 1);
  d := Pointer(Data);
  d^ := AnsiChar(pgCustomCode);
  Move(Pointer(aCustomCode)^, d[1], L);
  Windows.GdiComment(MetaHandle, L + 1, d);
end;

some changes:

  TPdfGDIComment = (pgcOutline, pgcBookmark, pgcLink, pgCustomCode);

procedure TPdfEnum.HandleComment(Kind: TPdfGDIComment; P: PAnsiChar; Len: integer);
.
.
.
      pgCustomCode:
        if Len > 0 then
        begin
          SetString(Text, P, Len);
          Canvas.Contents.Writer.Add(Text);
        end;

Last edited by Atys (2018-11-03 12:06:51)

Atys

Member

Registered: 2016-04-02

Posts: 13

Re: Non-Printable elements

Demo code:

  obPDF := TPdfDocumentGDI.Create;
  try
    obPDF.UseOptionalContent := True;
    obNonPrintableLayer := obPDF.CreateOptionalContentGroup(nil, 'Non-Printable', True, False);
    try
      obPDF.AddPage;

      obPDF.VCLCanvasBeginMarkedContent(obNonPrintableLayer);

      c := obPDF.VCLCanvas;
      c.Font.Name := 'Times new roman';
      c.Font.Size := 32;
      c.Font.Style := [fsBold, fsItalic];
      c.Font.Color := clNavy;
      c.TextOut(100, 100, 'Hello 1');

      obPDF.VclCanvasEndMarkedContent;

      c.TextOut(40, 40, 'Hello 2');

      obPDF.SaveToFile(ChangeFileExt(ExeVersion.ProgramFileName, '.pdf'));
  finally
    obPDF.Free;
  end;

Last edited by Atys (2018-11-03 12:13:39)

ab

Administrator

From: France

Registered: 2010-06-21

Posts: 14,272

Website

Re: Non-Printable elements

I am not sure I understand the need of this, and I honnestly don't have much time to investigate...

Tricking the GDIComment may be the right thing to do, but it sounds to me not as a clean way: I am always wondering if it may hurt some existing code.

The main problem with accepting such requests is that it is difficult to verify it won't break existing code used by other users - I have seen so many regressions when merging external code within SynPDF...