How to do pdf masking or text manipulation in pdf ?

[Laxmi530]

Hi,
I have a multi-page pdf wanted to mask certain fields in the pdf file, suppose like account number, phone number and name or wanted to replace other text in that place.

Can someone please guide me how to do this.
Thanking you in advance.

[JorjMcKie]

I presume you mean normal, standard text, when you say "field" - not PDF form fields?
The most important thing is how to identify the position of this items: the rectangle rect that wraps the respective text. Then use redaction annotations to remove all stuff inside the rectangle.
Like this:

import fitz
doc = fitz.open("input.pdf")
for page in doc:
    # somehow locate the items to make a list of rectangle "rects"
    for rect in rects:
        page.add_redact_annot(rect)
    page.apply_redactions()
doc.ez_save("output.pdf")

So far the easy part.
The above will produce empty (white) rectangle where one of the "rect" are.
You can also use any other color or show some other text instead.
How do you plan to identify the single rectangles?

[Laxmi530]

Hai @JorjMcKie
Thanks for your guidance.
I tried as you mentioned above but did not get the expected output. Below is the sample code and PDF file
which I used.

import fitz, os
file = 'Test_Document.pdf' 

def rect_name_size_color(file, words):
    with fitz.open(file) as pdf_file:
        rects = [rect for item in words for page in pdf_file for rect in page.search_for(item)]
        fontname = [text['font'] for page in pdf_file for item in words for rect in page.search_for(item)
                    for text in [page.get_text("dict", clip=rect)['blocks'][0]['lines'][0]['spans'][0]]]
        fontsize = [text['size'] for page in pdf_file for item in words for rect in page.search_for(item)
                    for text in [page.get_text("dict", clip=rect)['blocks'][0]['lines'][0]['spans'][0]]]
        text_color = [text['color'] for page in pdf_file for item in words for rect in page.search_for(item)
                    for text in [page.get_text("dict", clip=rect)['blocks'][0]['lines'][0]['spans'][0]]]
    return rects, fontname, fontsize, text_color

old_words = ['1234567890', 'At glance 1']
new_words = ['123 456 789', 'At_glance_1']

file_name = os.path.basename(os.path.splitext(file)[0])
rects, font_name, font_size, textcolor = rect_name_size_color(file, old_words)
with fitz.open(file) as pdf_file:
    for page in pdf_file:
        for rect in rects:
            page.add_redact_annot(rect)
        page.apply_redactions()
        quad = None
        text = None
        fontname = None
        fontsize = None
        text_color = None
        for rect_1 in rects:
            quad = rect_1
            for word in new_words:
                text = word
                for fnt_name in font_name:
                    fontname = fnt_name
                    for fnt_size in font_size:
                        fontsize = fnt_size
                        for txt_clr in textcolor:
                            text_color = txt_clr
        page.add_redact_annot(quad=quad, text=text, fontname=fontname, fontsize=fontsize, text_color=text_color)
    pdf_file.ez_save(f"Edited_{file_name}.pdf")

Test_Document.pdf
Edited_Test_Document.pdf

Please guide me where is the mistake.
Thanking you in advance.

[JorjMcKie]

Once you have applied redactions, you will have emtpy rectangles where old text was deleted, right?
You then must insert the replacement text. Instead you have added redaction annots again ...🙁

[Laxmi530]

Thanks @JorjMcKie for the response.
Yes right also I followed the Documentation but still I am not getting where is the mistake.

Please guide me the further steps.
Thanking you in advance.

[JorjMcKie]

Try this script:
test-JM.zip

[Laxmi530]

Thanks @JorjMcKie for the solutions.
It is working.