Python - How to properly fill a multiline text field in PDF form using pdfrw?

Question

I'm filling a PDF form using python with pdfrw. I have no problem with any single line text field in the form. But when I try to fill a multi-line textfield it doesn`t render properly, it ignores break lines.

This is part of my code:

pdf.Root.AcroForm.update(PdfDict(NeedAppearances=PdfObject('true')))

for x in range(0, len(pdf.Root.AcroForm.Fields)):
    try:
        if pdf.Root.AcroForm.Fields[x].T in ['(Observaciones)']:
            pdf.Root.AcroForm.Fields[x].update(PdfDict(V='This\nis\nmultiline', Ff=1))
            continue

This is the output.

This is the settings in the form field using Adobe Acrobat.

I have selected the options: Multiline, Scroll Long Text, Allow Rich Text Formatting.

I have tried using \r and the <br> tag too.

How should I set the value to render properly?

Uncheck "Permitir formato de texto enriquecido" (Allow Rich Text Formatting), and use \r (or \n) as line break. Note that Richt Text Formatting uses the richValue property, which has a rather complex structure. — Max Wyss, Jun 25 '21 at 06:56
I unchecked this option, tried \r (and \n) but it didn't changed the result. Text still in single line. — David Mendez, Jun 29 '21 at 19:22
No, it doesn't, it is set to None. Should I select any of the others? — David Mendez, Jul 14 '21 at 21:03
No; my suspicion was that there was a format preventing the proper multiline display. — Max Wyss, Jul 15 '21 at 07:59

score 1 · Accepted Answer · answered Jun 06 '22 at 00:52

After struggling with flattening my fields (setting to read-only) while keeping the multiline intact I finally found the solution.

I came across this rushed solution to just turn the ‘/Ff’ value to 1 but in doing so you run the chance of removing some of the formatting for the form, and here is a better explanation on how to manipulate this field.

In the ‘PDF Reference: third edition’ page:532 it states

“The value of the field dictionary’s Ff entry is an unsigned 32-bit integer containing flags specifying various characteristics of the field. Bit positions within the flag word are numbered from 1 (low-order) to 32 (high-order).“

So, when I looked into the Ff field I got 4096 (in binary = 0001-0000-0000-0000) for allot of the forms I was struggling with. Turns out that the 13th bit controls the multiline setting and just setting the Ff to 1 therefor erases the rest of the settings and only dictates that the specific form should be read-only.

You could just do it the lazy way and give Ff the value 4097 (or whatever your Ff value is +1) or flip the bit you want in the byte string that you want to manipulate.

Here is a simple way to do it, that is modifiable to your needs.

bitPosition = 0 #First position being value 0
bitValue = 1
mask = 1 << bitPosition
oldFfValue = pdf.Root.AcroForm.Fields[x].Ff
newFfValue = (int(oldFfValue) & ~mask) | ((1 << 0) & mask)
pdf.Root.AcroForm.Fields[x].Ff.update(PdfDict(Ff=newFfValue))

ps. Not 100% sure if accessing the Ff value works this way for you since my approach was based on this persons example code since it fit my needs better.

All in all I recommend giving the PDF reference document a look if you want to mess with the rest of the bits to see the interesting characteristics they control.

Other usefull bits are for example:

14th bit is for password star typing.
23rd bit is for disabling spell-check.
24th bit is for disabling scrolling of the field.

score 0 · Answer 2 · answered Jun 29 '21 at 18:14

0

I cannot read Spanish setting, but if you make sure these 2 fields are checked, then you probably will be OK.

Setting

answered Jun 29 '21 at 18:14

Frank Wang

1

2

As I wrote at the bottom of the image, I already checked those two options. – David Mendez Jun 29 '21 at 19:26

score 0 · Answer 3 · answered Aug 22 '21 at 15:17

I've had this issue too. I haven't delved into the implementation of the multi-line feature by pdfrw, but I do know that when I flatten the form field (Ff=1, which you also have in your code), it no longer supports multi-line. Try taking that off and see if multi-line is supported again.

score 0 · Answer 4 · edited Nov 27 '22 at 13:01

0

I set the the ff to 4097 and it seems to be working but need to check if it has impact on other things.

edited Nov 27 '22 at 13:01

Ophir Carmi

2,701
1
23
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answered Nov 23 '22 at 18:49

Joel Incan

1

1

Your answer could be improved with additional supporting information. Please [edit] to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers [in the help center](/help/how-to-answer). – Community Nov 27 '22 at 13:57

Python - How to properly fill a multiline text field in PDF form using pdfrw?

4 Answers4