Reading the PDF spec (PDF 32000-1:2008) is how I learned. I'd recommend
starting with section 7.1 (which is only one page), and then going
straight to section 7.7 (Document Structure) and referencing other
sections as you go along. Section 7.5 (File Structure) is also an
interesting read. For example 7.5.5 says "Conforming readers should read
a PDF file from its end." Once you know this, you can do the same thing
that all PDF software does (or at least, what they should be doing).
Hope this helps get you started. Happy reading.
----
Thanks,
Adam
From:
"Hesham G." <[email protected]>
To:
<[email protected]>
Date:
06/16/2011 11:09
Subject:
Re: Is there a difference between Watermark & Stamp ?
Adam ,
Thanks a lot for the nice tips.
I really would like to start learning how to read PDF code to trace it. I
have searched for any books or tutorials explaining that, but I couldn't
find any.
Best regards ,
Hesham
---------------------------------------------
Included message :
I downloaded your file and uncompressed it using pdftk. After that I
just
opened it with a text editor and looked for anything which might be
interesting.
I found that there's an element which mentions something about an image
and transparency.
2 0 obj
<<
/Rotate 0
/pdftk_PageNum 1
/CropBox [0 0 612 792]
/MediaBox [0 0 612 792]
/Resources
<<
/ExtGState
<<
/GS8 21 0 R
/GS5 22 0 R
>>
/Font
<<
/F1 23 0 R
>>
/ProcSet [/PDF /Text /ImageB /ImageC /ImageI]
>>
/Parent 1 0 R
/Contents [24 0 R 25 0 R 26 0 R 27 0 R 28 0 R 29 0 R 30 0 R 31 0
R]
/StructParents 0
/Type /Page
/Group
<<
/CS /DeviceRGB
/Type /Group
/S /Transparency
>>
/Tabs /S
endobj
Tracing back, it turns out that this is the page element ("20 0" is the
root, "1 0" is the element which defines the pages, and "2 0" is page
1).
Now the /Contents of the page are what we're interested in, but
unfortunately they are all streams of data which means very little to
me.
I'm not sure if these are object streams, but I'd imagine so because
there
doesn't seem to be any indication of the type. If you can find a way to
get these in a more human-readable format, you should be able to
continue
reverse engineering the PDF to determine how the image is on there. Once
you know that, you'll know exactly what you want to do. Then it should
just be a matter of checking the PDF reference to fully understand
what's
going on and what output you need from PDFBox. It's important you get
comfortable with tracing through a PDF in a text editor; this is the
only
way you'll be able to track down issues.
I usually just search the PDF source for the keyword that I'm looking
for
when I'm looking for a new feature and then trace the code back to try
to
understand how it is used and what the key classes are. Once I know
what
classes to use, I hit the documentation and search the Internet for
examples. If that doesn't work, check the user mailing list and see if
anyone has any suggestions. If not, check the dev mailing list to see
if
the functionality currently exists and if not, if anyone has any
suggestions on where you should implement it.
----
Thanks,
Adam
From:
"Hesham G." <[email protected]>
To:
<[email protected]>
Date:
06/16/2011 07:34
Subject:
Re: Is there a difference between Watermark & Stamp ?
Adam ,
This post is old, but I am still facing problems using the watermark,
and
I need it badly.
I have created a Microsoft word doc file with a watermark and I saved it
as a PDF file, and it appears just as I want. Now I am looking for a way
for how to do this with PDFBox. You can check this 1 page sample PDF :
http://www.4shared.com/document/rQ2berMh/pdf_with_watermark.html
Any help would be appreciated.
Best regards ,
Hesham
---------------------------------------------
Included message :
Sorry, but I can't give you any code examples for I have never done any
work with stamps nor watermarks. All I did was read the manual because
when I saw your question I thought "Hmm, that's a good question!"
What you describe sounds correct in terms of how it works, but it looks
like there is also an option to have the watermark not appear at all on
the PDF (when rendered on the screen), but appear when it is printed.
I'm
not sure if that's something you are interested in, but it's an option
as
far as I can tell.
Your best bet would be to find a PDF with a watermark, then extract a
single page. This will give you a small PDF with a watermark and you
should be able to go through it by hand (i.e. a good text editor). Just
search for "watermark" and see what comes up and then when you find
something in the PDF, see what references it and check the spec to get
some more information about what you're looking at. For example, if
you
see object "72 0" is a watermark, search for things which reference 72
0.
If you keep doing this you'll eventually get back to the root. If you
keep notes, you should have a nice map of how everything is connected.
I've done this for other objects and in combination with the spec, it's
worked out pretty well. Remember, you can also make modifications to
the
PDF using a text editor to see what it does (just remember to back up
the
original before you go hacking up the PDF or you'll probably end up
with
a
corrupt document).
----
Thanks,
Adam
From:
"Hesham G." <[email protected]>
To:
<[email protected]>
Date:
11/11/2010 03:15
Subject:
Re: Is there a difference between Watermark & Stamp ?
Adam ,
Thanks a lot for you reply, and sorry for being that late ... You're
always
here Adam when I need an answer.
I have this in PDF reference 1.7, but I do not understand that Adobe
code
:)
If you can translate this to me or give me a PDFBox code example, that
will
be very helpful.
In general, what I understand is that both watermarks and stamps both
can
be
images that appear in the PDF, but a watermark will appear in the
background, so if there was a text above it, the text will appear
normally.
In addition a watermark will appear as a part of the page, so it can't
be
clicked to show a notice box, as happens in a Stamp.
If this is wrong I hope you can correct me. if it's right, then
watermarks
is what I am looking for.
Best regards ,
Hesham
---------------------------------------------
Included message :
Hesham,
Take a look at table 102 in section 8.11.4.4 (Usage and Usage
Application
Dictionaries) of the PDF spec (I'm looking at version 1.7).
"A dictionary specifying that the content in this group is shall be
used
when printing. It may contain the following optional entries:
Subtype A name object specifying the kind of content controlled by the
group; for example, Trapping, PrintersMarks and Watermark.
PrintState A name that shall be either ON or OFF, indicating that the
group shall be set to that state when the document is printed from a
conforming reader."
For more information on the subtypes, see section 12.5.6.1, and
12.5.6.22
for specific details about a watermark.
I didn't read all the sections I just references, but after a quick
look,
it seems the main difference is that watermarks only appear on printed
documents, where images would appear when viewing the document as
well.
PDFBox might already support watermarks, but if it doesn't it could
probably be added without too much difficulty. Section 12.5.6.22 has
a
nice example of how it's laid out in the PDF which you could
reference.
You could also use that to either verify that your test document
actually
has a real watermark, or to manually add a watermark to one of your
test
documents.
----
Thanks,
Adam
----- Forwarded by Adam Nichols/UR/CER/XLDynamics on 11/09/2010 12:04
-----
From:
Adam Nichols/UR/CER/XLDynamics
To:
[email protected]
Cc:
"pdfbox-send-question" <[email protected]>
Date:
11/08/2010 09:13
Subject:
Re: Is there a difference between Watermark & Stamp ?
Take a look at table 102 in section 8.11.4.4 (Usage and Usage
Application
Dictionaries) of the PDF spec (I'm looking at version 1.7).
"A dictionary specifying that the content in this group is shall be
used
when printing. It may contain the following optional entries:
Subtype A name object specifying the kind of content controlled by the
group; for example, Trapping, PrintersMarks and Watermark.
PrintState A name that shall be either ON or OFF, indicating that the
group shall be set to that state when the document is printed from a
conforming reader."
For more information on the subtypes, see section 12.5.6.1, and
12.5.6.22
for specific details about a watermark.
I didn't read all the sections I just references, but after a quick
look,
it seems the main difference is that watermarks only appear on printed
documents, where images would appear when viewing the document as
well.
PDFBox might already support watermarks, but if it doesn't it could
probably be added without too much difficulty. Section 12.5.6.22 has
a
nice example of how it's laid out in the PDF which you could
reference.
You could also use that to either verify that your test document
actually
has a real watermark, or to manually add a watermark to one of your
test
documents.
----
Thanks,
Adam
From:
"Hesham G." <[email protected]>
To:
"pdfbox-send-question" <[email protected]>
Date:
11/07/2010 00:53
Subject:
Is there a difference between Watermark & Stamp ?
Hello everyone ,
What is the difference between a watermark and a stamp in PDF ?
I have seen nice examples in PDFBox to create stamps, but none to
create
watermarks. I guess it is not supported yet !
Best regards ,
Hesham
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- Warehouse Lines; FHA-Authorized Originators
- Lending and Servicing in over 45 States
www.swmc.com - www.simplehecmcalculator.com
Visit www.swmc.com/resources for helpful links on Training,
Webinars,
Lender Alerts and Submitting Conditions
This email and any content within or attached hereto from Sun West
Mortgage Company, Inc. is confidential and/or legally privileged. The
information is intended only for the use of the individual or entity
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on this email. If you are not the intended recipient, you are hereby
notified that any disclosure, copying, distribution or taking any action
in reliance on the contents of this email information is strictly
prohibited, and that the documents should be returned to this office
immediately by email. Receipt by anyone other than the intended
recipient
is not a waiver of any privilege. Please do not include your social
security number, account number, or any other personal or financial
information in the content of the email. Should you have any questions,
please call (800) 453 7884. =
- FHA 203b; 203k; HECM; VA; USDA; Conventional
- Warehouse Lines; FHA-Authorized Originators
- Lending and Servicing in over 45 States
www.swmc.com - www.simplehecmcalculator.com Visit
www.swmc.com/resources for helpful links on Training, Webinars, Lender
Alerts and Submitting Conditions
This email and any content within or attached hereto from Sun West
Mortgage Company, Inc. is confidential and/or legally privileged. The
information is intended only for the use of the individual or entity
named
on this email. If you are not the intended recipient, you are hereby
notified that any disclosure, copying, distribution or taking any action
in reliance on the contents of this email information is strictly
prohibited, and that the documents should be returned to this office
immediately by email. Receipt by anyone other than the intended
recipient
is not a waiver of any privilege. Please do not include your social
security number, account number, or any other personal or financial
information in the content of the email. Should you have any questions,
please call (800) 453 7884.
- FHA 203b; 203k; HECM; VA; USDA; Conventional
- Warehouse Lines; FHA-Authorized Originators
- Lending and Servicing in over 45 States
www.swmc.com - www.simplehecmcalculator.com Visit
www.swmc.com/resources for helpful links on Training, Webinars, Lender
Alerts and Submitting Conditions
This email and any content within or attached hereto from Sun West
Mortgage Company, Inc. is confidential and/or legally privileged. The
information is intended only for the use of the individual or entity named
on this email. If you are not the intended recipient, you are hereby
notified that any disclosure, copying, distribution or taking any action
in reliance on the contents of this email information is strictly
prohibited, and that the documents should be returned to this office
immediately by email. Receipt by anyone other than the intended recipient
is not a waiver of any privilege. Please do not include your social
security number, account number, or any other personal or financial
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