Centering on free_text()

[delta2echo]

I apologize if this can already be done, but there does not seem to be a way to center justify text when creating annotations.
It's possible to format the text in other ways, but no way to justify the text.

Is this a feature that's planned for the future?

[MartinThoma]

Is this a feature that's planned for the future?

That is an interesting question. In general, I think pypdf should (directly) support core-pdf features. And only those. That means if you can find it in the PDF specification, pypdf should support it. If it's not in there, pypdf should not support it. The one exception is text extraction.

I have seen /TextAlign /Justify in Table 344 – Additional standard layout attributes specific to block-level structure elements.

I guess you are talking about the FreeText annotation?

Hence the following should center your annotation text:

free_text_annotation[NameObject("/Q")] = NumberObject(1)

Feel free to add a PR to add this in generics/_annotations.py::free_text as a text_align parameter of type `Literal['left', 'center', 'right'] :-)

[delta2echo]

Assuming you mean this section (https://github.com/py-pdf/pypdf/blob/main/pypdf/generic/_annotations.py#L75-L144)
Something like this?:

class AnnotationBuilder:
   ...
   @staticmethod
    def free_text(..., 
                  text_align:str="left"
                   )-> DictionaryObject:
    
    ... 
    
    free_text = DictionaryObject()
    
    ... 
    
   text_align =text_align.lower()
    if text_align in ("center", "right"):
           free_text[NameObject("/Q")] = NumberObject({"center":1, 
                                                       "right":2}[text_align])
           
    ....
    
    return free_text

[MartinThoma]

Yes, exactly!

I would make it a keyword-only parameters though. Hence:

   @staticmethod
    def free_text(..., 
                  *,  # <--- that makes all following parameters to be keyword-only
                  text_align:str="left"
                   )-> DictionaryObject:

[MartinThoma]

Also, please then extend the test: https://github.com/py-pdf/pypdf/blob/main/tests/test_generic.py#L708-L745

[delta2echo]

just for the sake of being complete, I think this is the full changes needed:

class AnnotationBuilder:
   ...
   @staticmethod
    def free_text(..., 
                  *,
                  text_align:str="left"
                   )-> DictionaryObject:
     
     text_align =text_align.lower()                                              #<----Bring this to the top. 
     if text_align not in ("left","center","right"):                             #<----Not sure if you want this but I would put it in.
          raise ValueError("Only: 'left', 'center', 'right' are acceptable text alignment values.")
          
    font_str = "font: "
    ... 
    font_str = f"{font_str};text-align:{text_align};color:#{font_color}"         #<--- This change is necessary as well
    ... 
    free_text = DictionaryObject()
    
    ... 
    if text_align in ("center", "right"):
           free_text[NameObject("/Q")] = NumberObject({"center":1, 
                                                       "right":2}[text_align])
           
    ....
    
    return free_text

[pubpub-zz]

@MartinThoma / @delta2echo
use of an enum type might be better than str (easier to code using the hints)

[pubpub-zz]

also, shouldn't we wait for conclusion from #1741 ?

[MartinThoma]

Yes, we should probably wait for #1741 to come to a final conclusion.

[delta2echo]

When do you expect #1741 to be resolved? (just a rough guess is good)

[MartinThoma]

I guess 23rd of April. I want to finish #1745 with the current comments / missing parts this week. Then we have some time to discuss / iron out any issues. If / once we merge #1745, it will close #1741