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@waylan
Last active Sep 16, 2022
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A PDF fillable textfield which flows with text on a page using Reportlab.
from reportlab.platypus import SimpleDocTemplate, Flowable, Paragraph
from reportlab.lib.styles import getSampleStyleSheet
style = getSampleStyleSheet()['BodyText']
class TextField(Flowable):
def __init__(self, **options):
Flowable.__init__(self)
self.options = options
# Use Reportlab's default size if not user provided
self.width = options.get('width', 120)
self.height = options.get('height', 36)
def draw(self):
self.canv.saveState()
form = self.canv.acroForm
form.textfieldRelative(**self.options)
self.canv.restoreState()
class ChoiceField(Flowable):
def __init__(self, **options):
Flowable.__init__(self)
options['relative'] = True
self.options = options
# Use Reportlab's default size if not user provided
self.width = options.get('width', 120)
self.height = options.get('height', 36)
def draw(self):
self.canv.saveState()
form = self.canv.acroForm
form.choice(**self.options)
self.canv.restoreState()
doc = SimpleDocTemplate('textfield.pdf')
Story = [
Paragraph('First Name', style=style),
TextField(name='first_name', value='John', tooltip='First name', height=18),
Paragraph('Last Name', style=style),
TextField(name='last_name', value='Doe', tooltip='Last name', height=18),
Paragraph('Gender', style=style),
ChoiceField(name='gender', tooltip='Gender', value='male', options=['', 'male', 'female'], height=18)
]
doc.build(Story)
@waylan
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waylan commented Jun 17, 2021

I started by using this and this. This was also helpful in understanding how to use form fields, although it demonstrates absolute positioning them on the page (Reportlab's default behavior).

The resulting document (from the first version of this script) looks like this:

Untitled

@waylan
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waylan commented Jun 23, 2021

I encountered two bugs when adding the ChoiceField.

  1. canvas.acroform.choiceRelative is a textfield, not a choice. Therefore, I had to use choice and manually set options['relative'] = True.

  2. A choice always fails if a value it not provided. Passing in an empty value does not fix the issue, even if an empty value is included in options. Therefore, a default (non-empty) value must always be provided. Unfortunately, this is not always desired. Sometimes we want to start out with a blank form field.

    Whenever, value='' is passed in I get the following error:

       File "textfield.py", line 36, in draw
         form.choice(**self.options)
       File "C:\code\md2pdf\venv\lib\site-packages\reportlab\pdfbase\acroform.py", line 1008, in choice
         return self._textfield(
       File "C:\code\md2pdf\venv\lib\site-packages\reportlab\pdfbase\acroform.py", line 844, in _textfield
         **lbextras
     UnboundLocalError: local variable 'lbextras' referenced before assignment
    

@karlb
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karlb commented Jun 1, 2022

Thanks, this has been very helpful!

@bthorben
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bthorben commented Sep 6, 2022

Did you manage to make the resulting boxes editable? I get such boxes (as a checkbox), but they are not editable (tried Preview.app and Adobe Acrobat Reader DC):
image

@bthorben
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bthorben commented Sep 6, 2022

BTW: In the way you are using it self.width and self.height is ignored. I created a text field (screenshot above of the generated PDF) for our purposes like this:

class TextFormField(Flowable):
    def __init__(self, tooltip, name, width=120, height=26):
        Flowable.__init__(self)
        self.tooltip = tooltip
        self.name = name
        self.width = width
        self.height = height

    def draw(self):
        self.canv.saveState()
        form = self.canv.acroForm
        form.textfieldRelative(
            name=self.name,
            tooltip=self.tooltip,
            width=self.width,
            height=self.height,
            borderStyle='inset',
            forceBorder=True
        )
        self.canv.restoreState()

@karlb
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karlb commented Sep 8, 2022

I didn't try checkboxes, so I can't comment on that. I also noticed that width and height are not properly forwarded to textfieldRelative in the original example. My implementation is

class TextField(Flowable):
    def __init__(self, **options):
        Flowable.__init__(self)
        options["width"] = options.get("width", 135)
        options["height"] = options.get("height", 12)
        options["fontSize"] = options.get("fontSize", 10)
        self.options = options

    def draw(self):
        self.canv.saveState()
        form = self.canv.acroForm
        form.textfieldRelative(**self.options)
        self.canv.restoreState()

@bthorben
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Okay, I figured out why this didn't work. It was actually a problem with the way we handle the pdf afterwards. We have a background PDF on which we put this form. We merge them with QPDF. QPDF confuses the fonts uses in the two pdf and creates a problem. It's okay, but not helpful that reportlab uses /F1 /F2 and so on for font names and doesn't let us change the prefix. We made a monkey-patch to change the prefix to ATF so fonts are /ATF1 /ATF2 and so on, this merges then correctly

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