Adobe Community : Popular Discussions - PDF Language and Specifications

How to permanently rotate pdf 90 deg?

forums_noreply@adobe.com — Thu, 10 Jul 2008 17:40:56 GMT

Whenever I open a certain pdf doc it is shown clockwise rotated by 90 deg.
Ok I can de-rotate it by clicking the appropriate menu in Adobe Reader.

But is there a way to save this pdf so that it is automatically shown correctly at next opening WITHOUT having to explicitely rotate it through AR menues?

If yes: How?

PC users can't save PDF form data from form created on Mac

forums_noreply@adobe.com — Thu, 09 Feb 2012 20:27:54 GMT

I'm trying to create a PDF form for a client that will be accessing the form on a PC. However, when the client opens the form, a message appears saying that any data filled in the form cannot be saved and the document must be printed. If the client tries to "Save As" a message appears saying the form will be saved without the data. This defeats the whole purpose of using PDF forms.

What can I do to allow my client to save data in the form? When I check the permissions on my end, there is no security and no restrictions.

Developer environment:

Acrobat 9 Pro
OSX Snow Leopard

Client environment:

Windows 7
Acrobat Pro X

how to change font size in a call-out tool box?

forums_noreply@adobe.com — Wed, 31 Jan 2007 10:19:36 GMT

Hi, the other day i inserted a call-out tool box in a PDF document, however i cannot find anything that can change the font size of the letters i input in that box. could anyone help? Thanks.

Sherman

Mac PDF files not readable on PC

forums_noreply@adobe.com — Thu, 08 Feb 2007 00:32:43 GMT

I am constantly getting messages from my PC friends that the photoshop files I create and then convert to either pdf or jpg are not readable on their pc. Sometimes the files are split into two files (one very small and the other large) with the same name. The larger file is usually able to be opened.

What can I do to make my proofs easier to read for pc users? This has gotten frustrating.

Thanks for your help.

How I can translate a english pdf to spanish (stored in the Acrobat site)?

forums_noreply@adobe.com — Fri, 06 Jun 2014 01:10:12 GMT

Hello every body, Im start today in this site, im upload an a English PDF and i want to know if exist a tool to translate this document

How to use FlateDecode?

forums_noreply@adobe.com — Wed, 01 Dec 2010 10:24:35 GMT

Have a nice day to all!

My name is Alexander, I am a programmer. I try to open PDF file useing Delphi 2009, but I can't do it becouse I can't decode Flate stream. I have read next documents:

Document management — Portable document format — Part 1: PDF 1.7 (PDF 32000-1:2008)

Issue on the Deflate compressed PDU format

DEFLATE Compressed Data Format Specification version 1.3

and same other, and tried to use it information.

Also I try to use Zlib module in Delphi, but I get - "Data error".

I want to decode this part of file

H‰t”НЉ 1 …чэ х ]“¤’T 2 gP\ #.\ЛuьЃQРAaЮЮЇТЋ\ьбВMW'©:зФ©ѕxцйГчo·тдЙЕЛ« Ч’дттйх•l 7woO·пn®џ ;IЦЛЇ[ќEIч¦ҐИ0нMFR тнv{#_¶‹«ЧINч’EоO„П ?Ьo_y‘шeiЙµзJЋYµXkrъјЕЦзm ЪИєwµnІзЄ6:kУљ*kСдlз®#w9mq"Н¶Nш r·ЕSйхёлyЭй©GJ'E”9mп·Wзx<k‡’§М•t ‡ °›ZЖђЭІ6 в:&й›«; a0j 1G–*¦Ќ8i5—®УуїKZQ¶ј T8 ¦Щ$gM СИ9ҐT 5µµ,e"цЊ’0ќE,сє ’Ћf ¬uб2p uўЂЗЩ qbЩіNtЌL=ДУ>Й{Ае,ЭМYЂ ’ё .О "°< AыµЩs€ЯйУ|ЊAџ§GTљGФЖB?КB„¬@@/ ІйM2…!ґУ± ™ґД№В№‰ў©Gзµ"A ™ЙЏ@ЪаМБCШ‡їd®љ№ж ЖЉќй е`Ћ•qЌ=
Ш(ФЋ .Њ Vk‡еRnb‘
†8 CЈp_ ?љ 3М „` эраИ лД }ЉДЌ 2 FлБёR џM”Yмyvт `ь· dGwё Ґ FуОNe,ђ 0 ЫЗ?U(А Ќ Жg№хQ CхГlm© О к…¦С‚!\ґ 0КвAіJ2ђ ЌdѕFґ•( ‚™}
$Јн„ЮB M fЄ ЦХ- : юЭ,а ‘9М1‡н|* Б5г@ЌП Э?<йЎd¦ 3дM~XъА ћў» pm™}·¦y„ жвґгцiЛУђЋb»Щr9е 6a°УьЬЋOЛм‘kиљ%ч…ўN; И« =ы QЗїHЧ' WПybdґLФ¤Їtњ·ё± сaїџCпУ&? "Н О

who can describe me - how i can do it?

---------------------

Sorry for my English

Alexander

AES 256 Revision 6 (PDF 2.0) Encryption

forums_noreply@adobe.com — Mon, 19 Sep 2011 23:06:52 GMT

I am trying to implement decryption of AES 256 Revision 6 (PDF 2.0) as described in the ISO 32000-2 spec and having some success but getting some peculiar results that I cannot resolve and would appreciate some suggestions.

Using Acrobat X on a PC and encrypting using password encryption compatible with Acrobat X, I created a set of about 20 Acrobat X encrypted PDF tests. When I ran these through our implementation to decrypt as following ISO 32000-2 particularly Algorithms 2.A and 2.B most decrypted successfully and produced correct output. However a few failed either in the authentication phase or in the intermediate key computation stage, with the latter showing an error by an invalid decryption of the first stream of PDF encountered. Next I tried another set of different tests and also got a similar pass rate. Finally I took one unencrypted PDF test and chose the same security settings of compatible with Acrobat X, restrict editing, and printing, and allowed print and used the same password for 15 generated versions of this PDF test. 13 of these 15 resultant encrypted tests ran successfully with our implementation of the Revision 6 decryption algorithm. Two failed, with one failing a match on both user and owner key and the other failing computing the intermediate owner key.

In the past when we have implemented earlier Revision 5 256 AES, or even older compatibility versions it always was the case that you either had the software working or you didn’t. And the new PDF 2.0 2B algorithm with 64+ hashes and 64+ aes encryptions of data along with 16 byte mod 3 math computations leaves little room for error.

I believe that Acrobat when encrypting is choosing a random AES IV and all data including input /U /O /UE, and /OE strings differ. Even for the case described above of the same input test, same password, and same Acrobat encryption options. Thus the input into Algorithm 2-B will differ but the output should for authentication match the first 32 bytes of the O or U key or should result in a correct final result for intermediate owner or user key if the corresponding match occurred above.

However for the few exceptions that fail the above decryption it is not easy to determine what went wrong. Just about any change to the implementation of Algorithm 2.B breaks all working test cases instead of giving a clue as to what the issue is. The possible suspects are the new SHA-384 and SHA-512 and the encrypt code. We have used SHA-256 and the AES decrypt portion in earlier implementation of revision 5 and had no problems. The AES and hash code we are using is from Gladman¹. I was wondering what others are using? It looks like Acrobat X is using RSA BSAFE Crypto – C² at least for FIPS. Could Leonard or somebody else at Adobe tell me if this RSA software is also used in general with Acrobat X?

And I think that it would be very beneficial to have and publish a set of test vectors given input into algorithm 2.B along with correct intermediate results for each step. For each hash – including which method used per step show hash results, and also encryption step results, number of steps beyond 64 minimum, as well as final result. For the 80% of tests I have working I could produce this info. For those tests I cannot get working I would need help. Perhaps someone at Adobe or elsewhere who has had greater success than I have can help? I can provide input for the problematic tests either through this forum or privately at David.Lincoln@csr.com.

1) http://www.gladman.me.uk/

2) http://blogs.adobe.com/security/2011/05/update-fips-validation-certificates-for-acrobat-an d-reader-x.html

Extract embedded fonts from pdf

forums_noreply@adobe.com — Sun, 25 Aug 2013 15:06:15 GMT

Please i want to ask about the ability to extract embedded fonts from pdf is easy or not? because i tried to extract fonts form specific pdfs but there are fonts that not valid files, why these files not valid? are there specific technique to extract fonts from pdf?

Axial shading pattern with different alpha

forums_noreply@adobe.com — Tue, 11 Nov 2014 16:51:57 GMT

Hi,

I'm trying to apply different alpha values to axial shading pattern when drawing and I've found PDF Axial Shading Pattern ranging opacity very helpful.

But what kind of soft mask (PDF 1.4) should I use (dictionary or image mask)? And how could I create that mask?

I wrote some pdf code based on my limited understanding of pdf 1.4 reference and that doesn't work.

40 0 obj

<</Type /Group

/Subtype /Transparency

/ColorSpace /DeviceGray

/BitsPerComponent 8>>

stream

333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333 3333333333333333333333333333333333333333333333333333333333333

endstream

endobj

17 0 obj

<</Type /Mask

/Subtype /Alpha

/G 40 0 R

endobj

18 0 obj

<</Type /ExtGState

/SMask 17 0 R

/ca 1

...

19-26 are FunctionType 2 linear gradient

...

26 0 obj

<</FunctionType 3

/Domain [0 1]

/Functions [19 0 R 20 0 R 21 0 R 22 0 R 23 0 R 24 0 R 25 0 R ]

/Bounds [0.25 0.25 0.5 0.5 0.75 0.75 ]

/Encode [0 1 0 1 0 1 0 1 0 1 0 1 0 1 ]

endobj

27 0 obj

<</Type /Pattern

/PatternType 2

/Shading <</ColorSpace /DeviceRGB

/Function 26 0 R

/ShadingType 2

/Coords [37.5 3347.82 187.5 3347.82]

/Extend [true true]>>

/ExtGState <<

/GS0 18 0 R

Can't construct a valid cross reference stream.

forums_noreply@adobe.com — Sat, 27 Sep 2014 12:38:15 GMT

I'm building a PDF generation library from scratch.

Currently I'm having trouble generating a valid crossreference stream, but I'm totally lost as to why it is invalid.

%PDF-1.7
%µ
0 0 obj
<<
/Pages 1 0 R
/Type /Catalog
>>
endobj
1 0 obj
<<
/Type /Pages
/Kids [2 0 R]
/Count 1
>>
endobj
2 0 obj
<<
/Parent 1 0 R
/Type /Page
/MediaBox [0 0 612 792]
/Contents 3 0 R
>>
endobj
3 0 obj
<<
/Length 0
>>
stream
endstream
endobj
4 0 obj
<<
/Type /XRef
/W [1 2 0]
/Size 6
/Length 16
>>
stream
...
endstream
endobj
startxref
254
%%EOF

The full pdf file can be found here: https://www.dropbox.com/s/mvn0xptf0lasb28/test.pdf?dl=0

According to the spec a PDF file can consist of only objects with exemption of the first line (the 2nd is a comment) and the part from startxref.

Any tips would be greatly appreciated.

For simplicitly I've added the stream (extract via a hex editor) below:

0A 01 00 0D 01 00 3E 01 00 77 01 00 CE 01 00 FE 0A

Note that the stream starts and ends with a newline character. There are 17 bytes and the last line ending is not part of the stream length.

The remaining bytes 16 bytes have 15 bytes of data, (the first line ending is ignored (right?)):

01 00 0D

01 00 3E

01 00 77

01 00 CE

01 00 FE

As far as I can tell this PDF file's cross reference stream is valid. Any help would be greatly appreciated!

Extracting files from Portfolio - problem with outlook email created portfolios

forums_noreply@adobe.com — Mon, 25 Mar 2013 17:43:23 GMT

Currently I have developed a plugin that can extract files from portfolios using:-

PDNameTree tree = PDDocGetNameTree(pdDoc, ASAtomFromString("EmbeddedFiles"));

and

PDFileAttachmentFromCosObj

But i've noticed with Outlook email created portfolios the above is PDNameTree invalid. any suggestions? is it under another atom string or something?

Thanks,

Lee.

How to check a PDF file for errors?

forums_noreply@adobe.com — Tue, 01 Apr 2008 09:52:22 GMT

I have created a PDF file manually. Adobe Reader shows an error message "The file is damaged but is being repaired." when I try to open this file.
How can I check, what is wrong with this file? Is there any checker or some way to examine the file and find an error line?

What should be the behavior of Background with shfil

forums_noreply@adobe.com — Thu, 13 Nov 2014 12:01:44 GMT

I have a simple PostScript file that uses a Radial shading dictionary and shfill operator.

</PageSize [300 300]>> setpagedevice

10 10 moveto

290 10 lineto

290 290 lineto

10 290 lineto

closepath

/DeviceCMYK setcolorspace

0 1 0 0 setcolor

fill

newpath

20 20 moveto

280 20 lineto

280 280 lineto

20 280 lineto

closepath

clip

95 20 translate

gsave

/ShadingType 3

/Coords [25 100 90 -10 75 0]

/Extend [false false]

/Background [0.35 0.35 0 0]

/ColorSpace /DeviceCMYK

/Function <<

/FunctionType 2

/Domain [0 1]

/C0 [0 0 0.50 0]

/C1 [0 0.50 0.50 0]

/N 1

shfill

grestore

showpage

When i drag this PostScript file in Adobe Distiller 11, it generates a PDF file contains the Background entry in the shading dictionary.

As per PLRM, shfill operator must ignore the Background entry if present.

is it correct?

Thanks

Raquib

PDF CID keyed font support

forums_noreply@adobe.com — Mon, 10 Nov 2014 12:00:44 GMT

Hi,

I understand that PDF supports embedded CFF font programs for composite fonts of type CIDFontType0 - the spec is clear.

But, does it support embedded font programs that are not CFF - ie. CIDFont with type 1 descendent for example?

The spec only mentions CFF when talking about type 1 composite fonts, but it isn't totally clear.

So, does PDF support embedded non-CFF programs for composite type 1 fonts?

regards

Steve

Do you want to save changes message while close pdf

forums_noreply@adobe.com — Fri, 04 May 2012 12:30:42 GMT

hi everyone...

I am very new to PDF programming

basically I wrote my program in notepad and I saved it as .pdf format

but when I open it and try to close it..it showing me pop up like do you want to save changes..which is I dont want to happen...

is any one have idea what changes i have to do or how i make my file readonly....

thnks in advance...

"Incorrect structure found in PDF file"?

forums_noreply@adobe.com — Mon, 27 Aug 2007 15:59:51 GMT

I put together multi-page seminar presentations by using the Acrobat "Create PDF from Multiple Files" command to join together individual PDFs acquired elsewhere or generated by Mathematica or Illustrator, and then reorganizing these pages in Acrobat.

Fairly often, when I try to Delete an unwanted one these pages using Acrobat's Document >> Delete Pages menu command I get the error message "An incorrect structure was found in the PDF file", and the page simply refuses to delete (workaround is then to move it to the end of the file.

Is there any way to cure or avoid these problems? Or a diagnostic I could run on the errant document? For example, to clean up the "incorrect structure" could I:

--Burst (Extract) the file back to individual pages, run each individual page through a Save or Save As process in Acrobat or Illustrator?

--Do the preceding on every page before assembling the first time?

--Buy a whole new suite of Adobe programs?

--?????????????

Doing a Save or Save As on the complete file doesn't seem to help.

[This happen on a MacBook running Tiger (OS 10.4), Acrobat 7.0 Standard, Illustrator CS 7.0. Send me an email; I'll forward a cc of one of these files.]

CIDFont and PDF

forums_noreply@adobe.com — Tue, 11 Nov 2014 14:20:43 GMT

Hi,

thanks to the lrosenth for the help with my question about support for CID keyed Type1 fonts in PDF.

I will make sure that I read the ISO PDF spec - it is more clear.

Sadly, I have another question:

I have a valid CIDFont (consists of a readable PS part and also binary data which I believe is _parts_ of a CFF font program, not the whole program).

The readable PS part has info like byte offsets to CharStrings and also the table that maps CID values to font/glyph (CIDMap)

The FreeType library will render glyphs from this font.

The binary parts appear to be the CIDMap and CharStrings etc - but not the usual CFF header stuff - ie. just the bits you need.

My question: Am I right that you cant put such a CIDFont in a PDF file as an embedded font program (as part of a composite CIDFontType0) ?

From my reading of the spec, a composite font (Type0) in PDF references a CIDFont dict that doesn't have any of the info that the PS CIDFont contains (such as byte offsets to charstring data etc)

and so it needs the complete CFF program - specified as /FontFile3 in the font descriptor.

regards

JLM

password encryption with 256 bit AES algorithm...???

forums_noreply@adobe.com — Tue, 09 Aug 2011 11:07:12 GMT

I have an application for the decryption of pdf passwords for 128 bit Rc4 and 128 AES. In this, i am doing 50 times MD5 using an encryption key. Its working well with this approach. But in case of 256 bit AES password security, It creates problem. What is the difference between 128 bit AES and 256 bit AES algorithms ? Please tell me what are the algorithmic steps for 256 bit AES password security ??

Digital signature Filter / SubFilter

forums_noreply@adobe.com — Wed, 25 Nov 2009 13:06:08 GMT

Hi,

i have a question regarding the use of digital signatures.

As a filter value i am usingPDF32000.bookAdobe.PPKLite but i am not quite sure about the SubFilter. As i understand there are three possible values:

PDF32000.book- adbe.pkcs7.detached
- adbe.pkcs7.sha1
- adbe.x509.rsa.sha1

Now i need to create PDF/A compliant pdfs and i read somewhere that it is not recommended (or not compliant?) to use

'adbe.x509.rsa.sha1' (pkcs#1 format). Instead one of the other two should be used.

Now since SHA1 is too weak only 'adbe.pkcs7.detached' (pkcs#7 format) remains.

But what does the 'detached' stands for?

Does it mean that the digest or the certicate have to be stored in an extra file? (Similar to the xml signing mechanism: "Enveloping signatures are over data within the same XML document as the signature; detached signatures are over data external to the signature element.") ?

Thanks for clarifying,

ToM

PDF from SQL data

forums_noreply@adobe.com — Mon, 16 Feb 2009 16:55:20 GMT

I'm looking for a technology that will help me create multiple formats of similar data from an SQL database into PDFs. I haven't found a sales rep at Adobe who knows if any of their products can do what I need and they recommended the user-to-user forums.

My web-based application will generate financial affidavits. I need a different template for each state, so I need to create these templates without getting too much into the code itself. The templates will need to draw similar data about assets, liabilities, income and expenses from my SQL database, but the data will be organized in different places on the end document depending on the state. Each state's template (some states have different formats for each county) will also have different fonts, borders, and labels, so I want to be able to create these templates easily, without getting into the code.

Do you know of any Adobe or other technology that can help me do this?

Simple pdf file leads to wrong output color, whats wrong?

forums_noreply@adobe.com — Wed, 08 Jan 2014 14:20:04 GMT

Hello,

i have a simple pdf file that just draws a rectangle filled with cmyk 1.0,0.35,0,0.28,

but the problem is, that this is not the color thats printed. Inkscape and gimp show

the wrong color too.

In the pdf file the color is selected with

1 0.35 0 0.28 K 1 0.35 0 0.28 k

so i do not know whats wrong here. Can anybody help?

Here is the link to the small uncompressed pdf file

http://www.opaya.de/skoepf/test.pdf

Content:

%PDF-1.5

%äðíø

4 0 obj

/Length 133

stream

q 1 0 0 1 72 769.89 cm 0 G 0 g 0 G 0 g 0 G 0 g 1 0.35 0 0.28 K 1 0.35 0 0.28 k q 0 -95 85.04 85.04 re f Q 0 G 0 g 0 G 0 g 0 G 0 g Q

endstream

endobj

6 0 obj

/Type/ObjStm

/N 5

/First 27

/Length 357

stream

5 0 3 47 7 112 2 181 1 297 <<

/ProcSet[/PDF/Text/ImageC/ImageB/ImageI]

/Resources 5 0 R

/Type/Page

/Parent 7 0 R

/Contents[4 0 R]

/Type/Pages

/Count 1

/Kids[3 0 R]

/MediaBox[0 0 595.28 841.89]

/Creator( XeTeX output 2014.01.08:1342)

/Producer(xdvipdfmx $0.7.8$)

/CreationDate(D:20140108141527+01'00')

/Pages 7 0 R

/Type/Catalog

endstream

endobj

8 0 obj

/Type/XRef

/Root 1 0 R

/Info 2 0 R

/Size 9

/W[1 2 2]

/Length 45

stream

^@^@^@ÿÿ^B^@^F^@^D^B^@^F^@^C^B^@^F^@^A^A^@^O^@^@^B^@^F^@^@^A^@Ç^@^@^B^@^F^@^B^A^B{^@^@

endstream

endobj

startxref

635

%%EOF

Arabic letters inside pdf!

forums_noreply@adobe.com — Tue, 25 Jun 2013 08:02:23 GMT

Hello All,

please I have an enquiry about how pdf store arabic letters inside it because when i extracted arabic letteres from pdf file I saw different unicode for each letter not the original unicode for arabic letters in the range(06##)???

please need any answer about this question!

Finding errors in a PDF

forums_noreply@adobe.com — Mon, 12 Nov 2012 08:19:22 GMT

I am generating some PDFs from scratch. One of the files opens fine in Acroba but it still clearly has a structural problem because if I check the file with the preflight in Acrobat it says thet the file is damaged and needs repair, and if I close the file without eding anything Acrobat asks if I want to save the file. Acrobat does not say what the problem is, and I am unable to find the problem by inspecting it. It is quite a basic file and is easily inspectible using a text editor.

I have tried validating the pdf using different validators, but I have found no validators which will report on "structural" problems in the file, so I have tried to inspect the file using a text editor and also a binary-editor to check that offsets of the objects are at the correct place and that the stream lengths are right.

I am unable to find any problems by inspecting it manually so I don't understand what I am missing. And I don't know of any tools which can do this.

(I have got Acrobat Pro 8, but I am not an expert in using it so I don't know if it can be used to "debug" the file)

Anyway, if anyonecan give me any hints on how to solve this, it would be much appreciated.

And, if anyone wants to take a look at my testfile, it can be downloaded from here: https://www.box.com/files/0/f/0/1/f_3946274006

Again, the file is easily readable in a text editor since none of the streams are compressed...

Thanks in advance for any help!!

PDF debugging tools?

forums_noreply@adobe.com — Wed, 30 May 2012 07:37:05 GMT

Are there any pdf "debugging" tools available, and if, what are they called?

When trying to generate some PDF-files from scratch it is sometimes quite a bit of work trying to figure out where the problem lies if there is something wrong with the file.

Acrobat will usually just say that file has error(s) and that it can't be opened. GSview (http://pages.cs.wisc.edu/~ghost/gsview/) will give a bit more info which might help a LITTLE, but not a whole lot.

I have also tried PDF "analyzers" like for example PDF Vole (http://java.net/projects/pdfvole), which of course gives you an overview of the structure of the document, but which is not that helpful when trying to find an error in the file.

Can anyone suggest a good program for finding errors in a PDF-file, if such a program exists?

Thanks alot in advance!

Check Page Orientation with /Rotate

forums_noreply@adobe.com — Wed, 02 Mar 2011 17:55:19 GMT

Hi, I'm caught in an age old battle between two providers;

We produce PDFs from a copier to then be sent by and EMail to a FAX provider. Recipients are getting pages which should be portrait, as landscape. In turn because the receiving FAX can't rotate it back, they lose the bottom component of the page.

Inside the produced PDF I can see the following;

/Type /Page
/Parent 3 0 R
/Rotate 270
/Resources 37 0 R
/MediaBox [ 0.000 0.000 841.680 595.080 ]
/CropBox [ 0.000 0.000 841.680 595.080 ]
/Contents [ 40 0 R ]

QUESTION IS: To me this looks like I'm getting an A4 page, landscape BUT rotated by 270 degrees which should translate to portrait. On that basis it seem that it is the email>FAX provider ignoring the /Rotate element. Is this statement correct?

The email>FAX provider says that it must be a problem on the copier because there is inconsistency as to how the PDF displays. In Acrobat it is portrait and looks fine. In Illustrator it is landscape. So, it's the copier. My explanation there is that Acrobat will probably obey the rotation because it's designed primarily for 'print views' - Illustrator isn't and therefore may display as it sees the page definition. Further, in Illustrator if you goto print preview it does rotate to portrait.

The copier manufacturer say they're observing the PDF specification fully so it can't be them and must be the FAX service. I agree with them.

Sorry for the massive post but I've tried to put as much info as I can after much delving into technologies I don't know a lot about.

Signature Dictionary 'Filter'

forums_noreply@adobe.com — Wed, 16 Dec 2009 09:37:00 GMT

I have a question about the 'filter' in the signature dictionary. It is defined as (taken from PDF 1.4 due to PDF/A):

Filter name (Required; inheritable) The name of the signature handler to be used for authenticating the field’s contents, such as Adobe.PPKLite, Entrust.PPKEF, CICI.SignIt, or VeriSign.PPKVS.

1.) A plugin is used to validate signatures, right? (please correct me if i am wrong here)

2.) Can the subfilter (like adbe.pkcs7.detached or adbe.pkcs7.sha1) also be used with other filters than adobe.ppklite?

2) The Adobe.PPKLite is the "default" plugin? (which every reader since 5.0 or so has)

3.) The other handlers are also part of acrobat? (such as entrust, verisign etc.)

4.) What must i do to register my own handler?

5.) What would happen if one would set the filter which is not existent?

Thanks for clarification,

ToM

PDF digital signatures for beginners

forums_noreply@adobe.com — Sat, 01 Aug 2009 14:53:34 GMT

I am developing a PHP application that automatically signs pdf files and I am very confused about certain aspects. I read the PDF specifications and managed through the part of adding annotation, objects, empty signature field, etc but I don't seem to understand anything about computing the hash for the /Contents in the signature dictionary. The documentation is pretty vague about this part. Here's what I am interested in:

what specific hash algorithm do I have to apply to the newly generated pdf file with the dummy signature?

(I should mention that I am inclining using for the /SubFilter adbe.pkcs7.detached or adbe.pkcs7.sha1,)

what is the content of the pkcs7 envelope and how do I generate it?

how to convert the pkcs7 envelope to hex?

I must mention I have no training in cryptography and I've come to this forum after a few days of documenting on the subject without any succes.

Online AI into PDF file convertion

forums_noreply@adobe.com — Tue, 23 Jan 2007 19:50:20 GMT

I need to perform an online conversion from an AI online generated file, into PDF.
This convertion is to be done online, in a web server.
I can't find the proper plug'in or software product to do that.
I need help!!
Thanks

How to find out the DPI of an existing PDF doc?

forums_noreply@adobe.com — Sun, 25 Jan 2009 11:42:31 GMT

When I print a doc/web page with a pdf printer driver then I can adjust the DPI for the print.

Ok. But how does this work the other way?
When I have a pdf doc and want to find out the DPI with which it is printed ?

How can I find out this value?

Matthias

Small Cap Fonts

forums_noreply@adobe.com — Fri, 01 Feb 2008 22:06:13 GMT

I am trying to figure out how to use a small cap font when creating a PDF document manually... for example:

7 0 obj
<<
/Type/Font
/Name /T5
/BaseFont/Helvetica,SmallCap
/Subtype/Type1
/Encoding /WinAnsiEncoding
>>
endobj

I've tried many different variations around this basic structure, and I have tried including a fontDescriptor

7 0 obj
<<
/Type/FontDescriptor
...
/Flags 131104 %NonSymbolic & Small Caps
...
endobj

Can anyone point me in the right direction?

Thanks!

Corey

File Attachment

forums_noreply@adobe.com — Wed, 16 May 2007 09:48:14 GMT

Could somebody provide me with example how I can pass file stream to PDF file as attachment?

/*code begins*/
pdDoc = PDDocOpenEx(pathMainFile, ASGetDefaultFileSys(), NULL, NULL, FALSE);//open mainPDF - all OK

ASFixedRect rcAnnot = {fixedZero, fixedZero, fixedZero, fixedZero };
pdPage = PDDocAcquirePage( pdDoc, PDDocGetNumPages( pdDoc ) - 1 );
pdAnnot = PDPageAddNewAnnot( pdPage, -2, ASAtomFromString("FileAttachment"), &rcAnnot );
PDAnnotSetTitle( pdAnnot, "SomeTitle", 9 );
//annotation created - all works fine.

ASFileSysOpenFile( NULL, pathAttachment, ASFILE_READ, &fileAttachment );
stmAttach = ASFileStmRdOpen( fileAttachment, 0 );

cosStmAttach = CosNewStream( cosDoc, true, stmAttach, 0, false, CosNewNull(), CosNewNull(), -1 );
ASStmClose( stmAttach );
/*code ends*/

The main question is following: What should I do next after opening Cos file stream? Because PDF specification is to blurred for me in this aspect. As I understand I should create some dictionary entries - but I can't understand what entries should be created(even their names differ in different part of specification) ad where they should be created in.

Help me, please.

Duplicate entries in the Fields array

forums_noreply@adobe.com — Mon, 25 Aug 2014 11:16:47 GMT

I came across a (strange) pdf and after an analysis it turned out that some of the fields occur multiple times in the Fields array.

Now when looking up the spec it states:

"An array of references to the document’s root fields (those with no ancestors in the field hierarchy)."

Is that a violation of the spec (although it doesn't state that explicitly)?

So how to deal with this kind of PDFs?

How can I check text rotation when extracting text from pdf file?

forums_noreply@adobe.com — Tue, 20 Aug 2013 11:45:36 GMT

If there are rotated text in pdf file how can I detect this rotation in the output stream??

Extract embedded xml from PDF/A-3b (also creation)

forums_noreply@adobe.com — Mon, 19 Aug 2013 11:19:17 GMT

Hello there,

in the context of a research project, we are currently trying to extract embedded xml from a PDF/A-3b document via code.

The project deals with establishing a new invoicing standard (Zugferd: ferd-net.de, only german). Invoices are expressed via xml, which is embedded in PDF/A.

What we are trying to archive is extraction of the xml via java code. For testing purposes, we are currently using an third party skd to extract the invoice-xml, by calling a .EXE file and then picking up the results in java.

I currently have only one valid example file that can be processed via this sdk. To get more data, i used the test version of acrobat pro to alter the embedded xml file. To be more specific, i deleted the embedded file, added a new xml file, and used preflight to make the PDF conform to /A-3b. Although the file seems to have the same properties as the original, it can no more be processed via the extraction sdk. Since messing around with acrobat does not seem to get me anywhere, i am now looking into extracting data from the pdf my self.

Is there any present implementation/library/solution for extracting data in a java context? The few third party tools i found are all based of a .net/windows native environment. I have heard rumors about Adobe giving out tools to extract embedded data from PDF/A?

How is it the other way around? Is it possible to embedd xml into a PDF via Java? Given there allready is PDF file which we can attach to.

I really appreciate reading and thanks for any help or input!

Greetings,

Florian

incorrect checkbox appearance

forums_noreply@adobe.com — Tue, 19 Mar 2013 09:40:43 GMT

Hello everyone,

I'm working on a program that generates interactive forms in PDF. I'd like to add a checkbox on the page but there is problem. When the checbox has focus, everything works ok. When the focus is out, the checbox loses its appearance and it is rendered in default graphics (that's incorrect for me).

You can see the problem here: http://home.zcu.cz/~struharv/000003-checkbox.pdf (it's a handmade pdf file to be easily readable). In chrome build-in viewer it works ok, but not in Acrobat.

I don't see what's wrong.

Thanks for your help.

%PDF-1.7


1 0 obj << % entry point
          /Type /Catalog
          /AcroForm << 
                    /DR 3 0 R
                    /Fields [101 0 R]
          >>
          /Pages 2 0 R
>>
endobj


2 0 obj <<   % Pages object
          /Type /Pages
          /MediaBox [0 0 200 200]
          /Count 1
          /Kids [ 
                    <<       % Page
                              /Type /Page
                              /Parent 2 0 R
                              /Resources 3 0 R
                              /Annots [101 0 R]
                              /Contents 5 0 R
                    >>
          ]
>>
endobj


101 0 obj <<
          /Type /Annot
          /Subtype /Widget
          /Rect [70 50 120 70]
          /AP <<
                    /N << /Yes 108 0 R /Off 109 0 R >>
          >>
          /AS /Yes
          /V /Yes
          /FT /Btn
          /T (checkbox1) 
>>
endobj


108 0 obj <<      
    /Type /XObject
          /Subtype /Form
          /BBox [0 0 50 20]
          /Resources 3 0 R
>>
stream
          0 0 50 20 re
          0.8 g
          f
          BT
                    /F1 12 Tf
                    0 g
                    7 5.908 Td
                    (checked) Tj
          ET
endstream
endobj


109 0 obj << 
          /Type /XObject
          /Subtype /Form
          /BBox [0 0 50 20]
          /Resources 3 0 R
>>
stream
          0 0 50 20 re
          0.6 g
          B
          BT
                    /F1 12 Tf
                    0 g
                    7 5.908 Td
                    (unchecked) Tj
          ET
endstream
endobj

3 0 obj <<      % Resources
    /Font <<
                    /F1 4 0 R
          >>
>>
endobj


4 0 obj <<      % Font
          /Type /Font
          /Subtype /Type1
          /BaseFont /Times-Roman
>>
endobj


5 0 obj << % page content
>>
stream
          BT
                    70 150 TD
                    /F1 12 Tf
                    (Hello, world!) Tj
          ET
endstream
endobj


trailer 
<<
  /Root 1 0 R
>>
%%EOF

Problem with transparent image

forums_noreply@adobe.com — Mon, 25 Jun 2012 17:07:23 GMT

Hi everyone,

I'm having problem with embedding transparent image to PDF. Thin border appears when viewing the document with Adobe Reader, Adobe Acrobat Pro and even with Foxit Reader. But there are no such border in the image.

After some experiments I found that this border appears on the edge of fully transparent black and fully opaque white areas. And changing fully transparent black color to fully transparent white removes the border.

Is this an expected behaviour of Adobe Reader or is it a bug? Could anyone explain in which other cases such artifacts may appear?

Thanks in advance.

how to create digital signature

forums_noreply@adobe.com — Thu, 10 May 2012 07:59:40 GMT

<</ByteRange[ 0 18705 23193 67300] /Contents<0000000000000000000000000000000000000000000000000000000000000000000000000000000 000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 0000>/Filter/Adobe.PPKLite/M(D:20120509154821+08'00')/Name(?z SN^s)/Prop_Build<</App<</Name/Exchange-Pro/OS[/Win]/R 655616/REx(10.1.0)/TrustedMode false>>/Filter<</Date(Jun 6 2011 19:55:44)/Name/Adobe.PPKLite/R 131104/V 2>>/PubSec<</Date(Jun 6 2011 19:55:44)/NonEFontNoWarn true/R 131104>>>>/SubFilter/adbe.pkcs7.detached/Type/Sig>>

I have completed diital signature apperances,then i want to sign the document througth by "Contents" name object.i want to do it in openssl,but i have don't konw the algorithm whith "/SubFilter/adbe.pkcs7.detached ",who can help me?

Why have a default user password feauture?

forums_noreply@adobe.com — Wed, 16 Feb 2011 22:36:45 GMT

Hi,

I (understood) read in the manual that there could be a default user password -

28 BF 4E 5E 4E 75 8A 41 64 00 4E 56 FF FA 01 08
2E 2E 00 B6 D0 68 3E 80 2F 0C A9 FE 64 53 69 7A.

If the file is encrypted based one this key, readers can open the file without having to prompt for password though the file is encrypted. I want to know whats the point of this? It provides no security. All it ensures is the reader be sophisticated enough to have a security handler. I don't see the point. Is there any advantage of having such a pdf with default user password?.What was the motivation behind this?

Thanks

Secure PDF using certificate

forums_noreply@adobe.com — Wed, 22 Sep 2010 04:42:31 GMT

Hi All,

I'm developing a secure PDF using certificate.

When I open the PDF I get acrobat security saying " A digital ID was used to encrypt this document but no digital ID is present to decrypt it.Make sure your digital ID is properly installed or contact the document author. "

Any help in resolving this issue is appreciated?

How large can a PDF file be?

forums_noreply@adobe.com — Mon, 13 Sep 2010 14:54:16 GMT

This question is not just strictly about the spec, it's also about what the most common readers will accept.

So the file offsets are 10-digit numbers, is the maximum safe offset 2,147,483647 or 4,294,967,296 or 9,999,999,999?

I understand about "large" files and older OSs and so on, and I don't care about ancient lame OSs with 32-bit max file sizes...

PKCS#7 Signature problem

forums_noreply@adobe.com — Wed, 10 Sep 2008 09:19:59 GMT

Hi, I have a problem with my PDF files generating PKCS#7 signatures, both adbe.pkcs7.sha1 and adbe.pkcs7.detached.
PKCS#1 is OK, using the certifcate as /Cert and not /Contents naturally, but I need PKCS#7 for having to insert TimeStamp info.
Acrobat reports ASN.1 parsing error/ Error encountered while BER decoding.
I enclose a short extract:
11 0 obj
<<
/Type/Sig
/Filter/Adobe.PPKLite
/SubFilter/adbe.pkcs7.sha1
/Name(Papyrus User)
/M (D:20080910112551)
/R 65541
/Contents(0\202\004\0200\202\003y\240\003\002\001\002\002\011\000\221\202\334`\271a\
\263l0\015\006\011*\206H\206\367\015\001\001\005\005\0000\201\2671\013\
0\011\006\003U\004\006\023\002AT1\0310\027\006\003U\004\007\023\020\
Maria Enzersdorf1+0\)\006\003\
U\004\012\023"ISIS Papyrus $Def\
ault certificate$1\0330\031\006\
\003U\004\013\023\022Evaluation Purpo\
se1\0350\033\006\003U\004\003\023\024www.isis-\
papyrus.com1$0"\006\011*\206H\206\367\
\015\001\011\001\026\025info@isis-papyru\
s.com0\036\027\015070320151112Z\
\027\015080319151112Z0\201\2671\0130\011\
\006\003U\004\006\023\002AT1\0310\027\006\003U\004\007\023\020Ma\
ria Enzersdorf1+0\)\006\003U\004\
\012\023"ISIS Papyrus $Defau\
lt certificate$1\0330\031\006\003U\
\004\013\023\022Evaluation Purpose\
1\0350\033\006\003U\004\003\023\024www.isis-pa\
pyrus.com1$0"\006\011*\206H\206\367\015\001\
\011\001\026\025info@isis-papyrus.\
com0\201\2370\015\006\011*\206H\206\367\015\001\001\001\005\000\003\
\201\215\0000\201\211\002\201\201\000\256od\026\314Uw\037\\\226M\010\
Q\006\344\351\033\324f\305\030\314\035S\374\217\2114\362\205\001\203\305\231\
%u\323\251*\351\364mR\374R\220\367*\220\037K\206\323\270\037$\
\312e\01082u\015GIz\212\217\2526\003UGYa6%\234\
\340\264N\374g\024\260\226\315$\302\012\033\275\236\203\357\301I\351\225\316\
!\214\232&\344\213\356\334\220\274\002=\327\013/p|\025\223}V\025\
\017\323\262\016\220#\002\003\001\000\001\243\202\001 0\202\001\0340\035\006\
\003U\035\016\004\026\004\024/\326xc$\004\321\332\317\277|\002\220v\
\202\301\)\034\332\2320\201\354\006\003U\035#\004\201\3440\201\341\200\024\
/\326xc$\004\321\332\317\277|\002\220v\202\301\)\034\332\232\241\201\
\275\244\201\2720\201\2671\0130\011\006\003U\004\006\023\002AT1\031\
0\027\006\003U\004\007\023\020Maria Enzersd\
orf1+0\)\006\003U\004\012\023"ISIS Pap\
yrus $Default certific\
ate$1\0330\031\006\003U\004\013\023\022Evaluat\
ion Purpose1\0350\033\006\003U\004\003\023\024\
www.isis-papyrus.com1$\
0"\006\011*\206H\206\367\015\001\011\001\026\025info@is\
is-papyrus.com\202\011\000\221\202\334`\271\
a\263l0\014\006\003U\035\023\004\0050\003\001\001\3770\015\006\011*\
\206H\206\367\015\001\001\005\005\000\003\201\201\000\237\371&\241\273\254\365\326\
l\363ZC%\217\020\305\3511\340\027:\337\376OU-\331U\222\200\
g\025B\307\323\331\236\304[P\022\254\363\032j\226KOE"\033\213\
h\376\242]\363\236\366X\227\235\272\320\366~\373\254UIA\026\243\235\
Bz\321\356c\316BK\211\355\235\244`a\265t\035\347y\37354\
H\342\010\235Q\007\337kJ\264\016[\3179Ig\255$\302\025]\272\
\300\240\254\304\314\225\210\222\3229)
/ContentInfo<0482008063CFA582E3F41AB66B045C211F49EF940A2A754CC891A132A7BEE5F80F94471048E16 9DDBA739CA6EC3A575B447213E0DBDAB893BE8A67AE9C3D36294524037FB71442D929934F26540EBBA4D7F9851 9325AD2486EC3FBDEE96046C3D6E7C5E1AA4C570A070B8849990D4413FCB2B0A2712286129602075B10BAC81ED 12909E100>
/ByteRange[0 4973 5241 603 ]
>>
endobj

when I clciked on the file to open it asked me to opne or save but i clciked on open it automatically a folder was opened path :->>windows->>Temporary Internet Files ->Content.IES->>

forums_noreply@adobe.com — Mon, 03 Nov 2014 07:21:59 GMT

Hi Guys,

Please let me know why it is opening like this?

Decompressing a cross reference stream with Params.

forums_noreply@adobe.com — Fri, 29 Aug 2014 04:14:21 GMT

I'm losing my mind trying to decompress this stream. I've asked everyone and am not having much luck with it. This is a cross reference stream with decode params.

I have used an external library for decompressing this and for some reason, the xref streams just cannot be decoded. I noticed that software designed to decompress pdf files such as Quick Pdf, VeryPdf etc will decompress all streams but these. So there must be something extra about the output of these that I don't understand.

A common error message would be that the stream cannot be displayed because it contains binary data. Very odd. Any clues.

25 0 obj

<</DecodeParms<</Columns 4/Predictor 12>>/Filter/FlateDecode/ID[<6647557224A6C102A60F6D82BB22C18D><AA383B5CF85B7F4BACB9D502B93 343E9>]/Index[10 20]/Info 9 0 R/Length 64/Prev 23381/Root 11 0 R/Size 30/Type/XRef/W[1 2 1]>>stream

hÞbbd ``b`Š ~@‚ñ `Ù $Øù€ W P°~.............compressed stream data.

endstream

endobj

If I add PDF files to my website , can the goodlebot read it?

forums_noreply@adobe.com — Thu, 28 Aug 2014 19:27:20 GMT

My website is [link removed] It is about education. Id like to add files about education to be downloaded by teachers bu I do not want them to be read by the googlebot. So If I add PDF files will the bot be able to read them?

Decompressing Xref Streams?

forums_noreply@adobe.com — Tue, 26 Aug 2014 14:50:21 GMT

I am having significant problems decompressing xref streams. Unfortunately the use of Params has complicated things a little.

I am using various open source libraries to do this but I just wanted to check if my understanding is right. The ISO3200 standard doesn't quiet put it in a way I can understand.

If I am returning a decompressed Xref stream to a buffer, can I output it as one long string (adhering to white space), or do I need to recognise the output another way. Such as Objects etc?

Are Xref streams and white space rules surrounding these streams the same as the rules for all other streams.

I have files written with Adobe 9 pdf printer, are the predictors in that version, relative to previous versions, different. I'm simply trying to decompress text streams and want the xref information to navigate the document.

If there is tips for decompressing these streams please add them as I could be here for the next two years trying to decompress a single

xref stream. Maybe that's the way it's supposed to be, I don't know.

Thanks

XMP updated with exiftool is not read

forums_noreply@adobe.com — Mon, 19 May 2014 13:05:36 GMT

If this question is better suited in another forum, please let me know.

The following example PDF has been used in a workflow where the XMP meta data has been updated with new values (e.g. dc:identifier has the value Metropoles).

When opening this file and looking at the meta data in for example Acrobat Pro this new updated information is not viewed but the old XMP stream is instead read by Acrobat (pdfLib).

The update looks correct as far as I can see, the object 54 has been updated and the new xref table at the end has the correct start byte for this new updated stream (byte 0022017676). So I can not understand why this new stream of XMP is not viewed in Acrobat.

Does anyone see any error in the PDF or is there any obvious reason why Acrobat wouldn't read the new XMP stream?

(other software using exiftools extract the new XMP correctly, I have also tested with some tool written in pure java and that will also show the new updated XMP as the currently working meta data)

Link to test PDF (appr 22 MB)

Dropbox - Test-20140518.pdf

TJ operator does NOT display all glyph

forums_noreply@adobe.com — Fri, 09 May 2014 15:40:27 GMT

Hi everyone,

I have a strange behaviour when generating a PDF document by using the TJ operator:

I am using the TJ to justify multibyte glyphs.

For example this:

BT 297.640 640.940 Td /F1 10.0 Tf () Tj /F2 10.0 Tf [(Lorum) 459 (Ipsum) 459 (dolar,) 459 (etc) 459 (June) 459 (4th,)] TJ /F1 10.0 Tf ET

is rendered correctly justified in Chrome viewer and Foxit Reader.

But the same PDF document in Acrobat Reader and Adobe Acrobat 9.0 is only showing "Lorum dolar, June".

So "Ispum", "etc" and "4th" are missing.

Acrobat Preflight reports the following error:

Any ideas?

Thank you in advance

change font in DA of FreeText Annotation

forums_noreply@adobe.com — Fri, 04 Apr 2014 17:36:31 GMT

I am trying to change the default appearance (the DA entry) of a FreeText annotation. To begin with, I can't find anywhere in Acrobat to change the font of a FreeText annotation. My understanding is that I need to create a font alias in DS entry of the AcroForm, then reference it using Tf operator in the DA entry.

Below is the smallest PDF code I created:

%PDF-1.6

%âãÏÓ

1 0 obj

<</Type/Catalog/Pages 2 0 R/AcroForm 3 0 R>>

endobj

2 0 obj

<</Type/Pages/Kids[4 0 R]/Count 1>>

endobj

3 0 obj

<</Fields[]/DR<</Font<</FNT1 5 0 R>>>>>>

endobj

4 0 obj

<</Type/Page/Parent 2 0 R/Resources<<>>/MediaBox[0 0 612 792]/Annots[6 0 R]>>

endobj

5 0 obj

<</Type/Font/Subtype/Type1/BaseFont/Times-Bold>>

endobj

6 0 obj

<</Type/Annot/Rect[10 400 160 570]/CreationDate(D:20140404131900-05'00')/Subtype/FreeText/Contents(OK, Let's just start a content.)/DA(/FNT1 9 Tf\n1 0 0 rg\n0 1 0 RG\n)>>

endobj

xref

0 7

0000000000 65535 f

0000000015 00000 n

0000000075 00000 n

0000000126 00000 n

0000000182 00000 n

0000000275 00000 n

0000000339 00000 n

trailer << /Size 7 /Root 1 0 R/ID[<da5bbc2c7a8acf9c73eb1fbda9cf31c6><da5bbc2c7a8acf9c73eb1fbda9cf31c6>]>>

startxref

525

%%EOF

Acrobat failed to display the FreeText annotation in new font and background. The document shows that the FreeText annotation uses Helvetica font, not Time-Bold.

What is wrong with my code?

Example font subset with non-unicode output

forums_noreply@adobe.com — Thu, 20 Mar 2014 10:47:05 GMT

Hi,

I am searching for an example to use a TTF Font as font subset in PDF but without UTF16 encoding.

Is this even possible?

Something similar to

7 0 obj
	<</Type /Font /Subtype /Type0 /BaseFont /AAAAAD+Arial/Encoding /Identity-H /DescendantFonts [9 0 R] /ToUnicode 8 0 R >>

9 0 obj
	<</Type /Font /Subtype /CIDFontType2 /BaseFont /AAAAAD+Arial /CIDSystemInfo << /Registry (Adobe) /Ordering (Identity) /Supplement 0 >> /FontDescriptor 11 0 R /W [...

But how does the rest should look like?

Thank you in advanced

Indexed png transparency using /Mask

forums_noreply@adobe.com — Fri, 21 Feb 2014 22:12:11 GMT

Hi,

is it possible to use an indexed png's palette and accompanying transparency data to display a masked image? I've seen enough evidence in other opensource pdf libraries to suggest that it's possible, but am having trouble getting it working myself.

The indexed PNG's i've tested all contain an array of palette data and an associated array of transparency values.

I'm able to successfully display the png in a pdf, when only using it's palette and excluding the transprancy. The transparent parts of the image are displayed as black, as expected . The outuput is,

17 0 obj

<</Type /XObject

/Subtype /Image

/Width 16

/Height 16

/ColorSpace [/Indexed /DeviceRGB 15 18 0 R]

/BitsPerComponent 4

/Filter /FlateDecode

/DecodeParms <</Predictor 15 /Colors 1 /BitsPerComponent 4 /Columns 16>>

/Length 155>>

stream

--------------- BINARY IMAGE DATA ---------------

endstream

endobj

18 0 obj

<< /Length 48>>

stream

--------------- PALETTE ARRAY VALUES AS BINARY ---------------

endstream

endobj

But as soon as i try an add the transparency array, nothing gets displayed and i get an error when opening the pdf that says 'An error exists on this page'. The transparency values for the indexed image are as follows,

[255, 255, 192, 192, 160, 160, 128, 128, 96, 96, 64, 64, 32, 32, 0, 0]

I've followed the spec, 8.9.6.4 Colour Key Masking, although i'm not sure if there should be a difference between 'min' and 'max' or whether it's just the same value duplicated? From the logic i've seen in other pdf generation libraries, it appears to be the latter.

This is the non working output i get, when attempting to use the above array of transparency values as a mask,

17 0 obj

<</Type /XObject

/Subtype /Image

/Width 16

/Height 16

/ColorSpace [/Indexed /DeviceRGB 15 18 0 R]

/BitsPerComponent 4

/Filter /FlateDecode

/DecodeParms <</Predictor 15 /Colors 1 /BitsPerComponent 4 /Columns 16>>

/Mask [255 255 255 255 192 192 192 192 160 160 160 160 128 128 128 128 96 96 96 96 64 64 64 64 32 32 32 32 0 0 0 0 ]

/Length 155>>

stream

--------------- BINARY IMAGE DATA ---------------

endstream

endobj

18 0 obj

<< /Length 48>>

stream

--------------- PALETTE ARRAY VALUES AS BINARY ---------------

endstream

endobj