Re: PDF problem - Help needed

It might be that the content is being rendered off the page; the example =
you supply would translate the content up 682.6 points (~241mm) and over =
253 points (~89mm). If the content is already located at this offset, =
that would be enough to move it off the page...


> On Sep 11, 2025, at 2:18=E2=80=AFPM, UDDHAV PHATAK 22BCE10731 =
<[email protected]> wrote:
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> Hi Michael,
> Thanks for the suggestion. following your suggestion, I realized I =
wasn=E2=80=99t actually adding the stream into the page=E2=80=99s =
content stream. After digging deeper into both my code and QPDF=E2=80=99s =
implementation, I started creating a dedicated content stream for each =
XObject. For example, for an XObject named Fxo1, I generated the =
following stream:
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> ```
> q
> 1.000000 0.000000 0.000000 1.000000 253.000000 682.600000 cm
> /Fxo1 Do
> Q
> ```
> The transformation matrix values come directly from the /Rect of the =
corresponding annotation object. I can now confirm that this stream is =
indeed being appended to the page content stream. However, the XObject =
still isn=E2=80=99t rendering or becoming visible in the output.
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> On Thu, Sep 11, 2025 at 8:32=E2=80=AFPM Michael Sweet =
<[email protected]> wrote:
> Till,
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> I don't have a lot of time to look at this right now, but from the =
standpoint of adding the appearance streams as XObject resources in the =
page dictionary, you still need to *draw* the objects from the page =
content stream using the "Do" operator.  For example, if the XObject was =
named "foo" then you'd need to add:
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>     /foo Do
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> to the content stream.
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> > On Sep 11, 2025, at 10:50=E2=80=AFAM, Till Kamppeter =
<[email protected]> wrote:
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> > [ This mail is addressed to people from whom I know that they have =
konwledge on
> >  the inner workings of the PDF file format due to the projects they =
are working
> >  on. ]
> >=20
> > Hi,
> >=20
> > Uddhav Phatak (CCed) has done a GSoC 2024 project on eliminating C++ =
in libcupsfilters, mainly by replacing the PDF manipulator QPDF by Mike =
Sweet's PDFio.
> >=20
> > His project report:
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> > =
https://medium.com/@uddhavphatak/gsoc-2024-final-report-the-refactor-repor=
t-a46756e9d6ce
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> > His code as PR #71 on libcupsfilters:
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> > https://github.com/OpenPrinting/libcupsfilters/pull/71
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> > Some parts he did not succeed to complete withing the GSoC time =
frame due to their complexity.
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> > What is remaining to be completed is flattening filled forms and =
annotations into static content of the PDF, so that the filled in text =
is correctly taken into account by doing page manipulations (like N-up) =
and that it is assured that the text gets printed.
> >=20
> > On this step Uddhav ran into a problem:
> >=20
> > -----
> > Hi Till,
> > I am not able to debug one issue, could you help me where I might be =
going wrong,
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> > form_english_filled.pdf and needtrue.pdf, both have needAppearances =
set as true.
> >=20
> > form_english_filled.pdf is successfully flattened as shown in =
test.pdf
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> > but when converting needtrue.pdf into needtrue-test.pdf, even though =
all the annotation objects are successfully converted to Xobjects and =
added into the page dict, I am not understanding why aren't they =
visible.
> >=20
> > Can you look through this and tell me where I might be going wrong, =
and what value is missing from the Xobject Dictionary.
> > -----
> >=20
> > The files mentioned here are all attached.
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> > Anybody has an idea what can be wrong here?
> >=20
> > Thanks in advance.
> >=20
> >   Till
> > <test.pdf><needtrue-test.pdf><needtrue.pdf><form_english_filled.pdf>
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> ________________________
> Michael Sweet
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________________________
Michael Sweet