Pdf

PDF

Work PDFs in the sandbox with preinstalled Python libs. Pick the library by task:

• Extract text/tables/layout/word-coordinates → pdfplumber; quick raw text or page ops → pypdf.
• Merge / split / rotate / crop / watermark / encrypt / metadata → pypdf.
• Fill forms → pypdf (fillable AcroForm fields) or annotation overlay (flat forms).
• Create from scratch → reportlab.

Use exec with complete Python source (language: python). Prefer creating, reopening, and validating the PDF in one call; later calls can revise the same relative filename. Follow the turn's User workspace instructions for locating inputs, output boundaries, and presenting the finished file. Preserve an explicitly requested quantity (such as 500 words) and verify the count in the output before finishing. If execution fails or the artifact is missing, diagnose stderr/root cause and change strategy; do not retry identical code or reduce the requested scope without asking.

Extract text and tables (pdfplumber)

pythonCopy code
import pdfplumber

with pdfplumber.open("in.pdf") as pdf:
    for i, page in enumerate(pdf.pages, 1):
        print(f"--- page {i} ---")
        print(page.extract_text() or "")  # layout-aware text
        for t in page.extract_tables():  # list of tables; each is list[row]
            for row in t:
                print(row)

Tables → Excel (one worksheet per table):

pythonCopy code
import pdfplumber
from openpyxl import Workbook

workbook = Workbook()
workbook.remove(workbook.active)
table_number = 0
with pdfplumber.open("in.pdf") as pdf:
    for page_number, page in enumerate(pdf.pages, 1):
        for table in page.extract_tables():
            if not table:
                continue
            table_number += 1
            sheet = workbook.create_sheet(f"p{page_number}_table{table_number}"[:31])
            for row in table:
                sheet.append([cell or "" for cell in row])
if table_number:
    workbook.save("tables.xlsx")

Messy tables: pass strategies, or crop a region with page.within_bbox((x0, top, x1, bottom)) first:

pythonCopy code
ts = {
    "vertical_strategy": "lines",
    "horizontal_strategy": "lines",
    "snap_tolerance": 3,
    "intersection_tolerance": 15,
}
page.extract_tables(ts)

For very large PDFs where you only need raw text, pypdf's page.extract_text() is lighter.

Scanned / image-only PDFs (be honest)

If extract_text() returns empty or garbage (e.g. (cid:NN) runs) the page is scanned. No OCR engine (tesseract) is installed and network is off, so you cannot recover that text. Say so plainly and stop — do not fabricate content or attempt pip install.

Merge / split / rotate / crop / metadata (pypdf)

pythonCopy code
from pypdf import PdfReader, PdfWriter

# Merge
w = PdfWriter()
for f in ["a.pdf", "b.pdf"]:
    for p in PdfReader(f).pages:
        w.add_page(p)
w.write("merged.pdf")

# Split: one file per page
r = PdfReader("in.pdf")
for i, p in enumerate(r.pages, 1):
    w = PdfWriter()
    w.add_page(p)
    w.write(f"page_{i}.pdf")

# Rotate page 0 by 90 degrees clockwise
r = PdfReader("in.pdf")
w = PdfWriter()
r.pages[0].rotate(90)
w.add_page(r.pages[0])
w.write("rotated.pdf")

• Metadata: PdfReader("in.pdf").metadata (.title, .author, ...).
• Crop: set page.mediabox.left/bottom/right/top (points, origin y=0 at bottom).
• Encrypt: w = PdfWriter(clone_from=PdfReader("in.pdf")); w.encrypt("userpw", "ownerpw"); w.write("enc.pdf").
• Decrypt: r = PdfReader("enc.pdf"); r.decrypt("pw") if r.is_encrypted, then read/copy pages.

Watermark (stamp one page over every page):

pythonCopy code
from pypdf import PdfReader, PdfWriter

wm = PdfReader("stamp.pdf").pages[0]
r = PdfReader("in.pdf")
w = PdfWriter()
for p in r.pages:
    p.merge_page(wm)
    w.add_page(p)
w.write("stamped.pdf")

Create PDFs (reportlab)

Flowing document (preferred for text/reports/tables — handles pagination):

pythonCopy code
from reportlab.lib.pagesizes import letter
from reportlab.lib.styles import getSampleStyleSheet
from reportlab.lib import colors
from reportlab.platypus import SimpleDocTemplate, Paragraph, Spacer, Table, TableStyle

styles = getSampleStyleSheet()
story = [
    Paragraph("Report Title", styles["Title"]),
    Spacer(1, 12),
    Paragraph("Body text. " * 20, styles["Normal"]),
]
data = [["Product", "Q1", "Q2"], ["Widgets", "120", "135"]]
tbl = Table(data)
tbl.setStyle(
    TableStyle(
        [
            ("BACKGROUND", (0, 0), (-1, 0), colors.grey),
            ("TEXTCOLOR", (0, 0), (-1, 0), colors.whitesmoke),
            ("GRID", (0, 0), (-1, -1), 0.5, colors.black),
        ]
    )
)
story += [Spacer(1, 12), tbl]
SimpleDocTemplate("out.pdf", pagesize=letter).build(story)

Absolute placement (labels at fixed coordinates): use canvas.Canvas("out.pdf", pagesize=letter), c.drawString(x, y, "...") (origin bottom-left, points), c.showPage() per page, c.save().

Non-Latin text (Chinese / Japanese / Korean, Cyrillic, …)

reportlab's built-in fonts (Helvetica/Times/Courier) carry zero CJK glyphs, so any 中文/日本語/한국어 renders as empty boxes (□) baked permanently into the PDF. reportlab never auto-discovers system fonts — you MUST register a font that has the glyphs and set it on every style. Whenever the document may contain non-Latin text, register a CJK font first (it also covers Latin, so it is safe to use as the only font):

pythonCopy code
import os
from reportlab.pdfbase import pdfmetrics
from reportlab.pdfbase.ttfonts import TTFont


def register_cjk_font(name="CJK"):
    # TrueType ONLY — reportlab cannot embed CFF/OpenType outlines, so a .otf
    # like Noto Sans CJK fails with "postscript outlines are not supported".
    for path in [
        "/usr/share/fonts/truetype/wqy/wqy-zenhei.ttc",  # Linux sandbox (fonts-wqy-zenhei)
        "/usr/share/fonts/truetype/wqy/wqy-microhei.ttc",
        "/System/Library/Fonts/STHeiti Light.ttc",  # macOS
        "/System/Library/Fonts/Hiragino Sans GB.ttc",
        "/System/Library/Fonts/Supplemental/Songti.ttc",
        "/System/Library/Fonts/Supplemental/Arial Unicode.ttf",
        "C:/Windows/Fonts/msyh.ttc",  # Windows
    ]:
        if os.path.exists(path):
            try:
                pdfmetrics.registerFont(TTFont(name, path, subfontIndex=0))
                return name
            except Exception:
                continue
    raise RuntimeError("No CJK-capable TrueType font found — do not emit tofu; say so.")


font = register_cjk_font()
styles = getSampleStyleSheet()
for s in styles.byName.values():  # make the CJK font the default everywhere
    s.fontName = font
# Tables don't read the stylesheet — set the font in the TableStyle too:
#   ("FONTNAME", (0, 0), (-1, -1), font)
# Canvas: c.setFont(font, size) before every drawString.

If register_cjk_font raises (no font on the host), do not ship a tofu PDF — tell the user the sandbox lacks a CJK font instead of producing garbage.

Gotcha: even with a good font, reportlab still needs markup for subscripts/superscripts. In Paragraph use Paragraph("H<sub>2</sub>O", styles["Normal"]), x<super>2</super>.

Markdown/HTML → PDF needs an external converter (soffice/pandoc) that is usually absent — command -v soffice / command -v pandoc and degrade to building the PDF directly with reportlab if neither is present.

Fill forms (pypdf)

First detect whether the PDF has real fillable (AcroForm) fields:

pythonCopy code
from pypdf import PdfReader

fields = PdfReader("form.pdf").get_fields()
print("fillable" if fields else "flat (no fields)")

Fillable — inspect field names/types, then fill and write:

pythonCopy code
from pypdf import PdfReader, PdfWriter

r = PdfReader("form.pdf")
for name, f in r.get_fields().items():
    print(name, f.get("/FT"), f.get("/_States_"))  # /Tx text, /Btn checkbox/radio, /Ch choice

w = PdfWriter(clone_from=r)
values = {"first_name": "Bart", "agree": "/Yes"}  # checkbox/radio: use its on-state, NOT True/False
for page in w.pages:
    w.update_page_form_field_values(page, values, auto_regenerate=False)
w.set_need_appearances_writer(True)  # force viewers to render the values
w.write("filled.pdf")

Checkbox/radio values are on-state strings, not booleans — read the field's /_States_ (e.g. /Yes, /On); /Off clears it.

Flat form (no fields) — overlay text with FreeText annotations at PDF coordinates. Get real coordinates from the layout with pdfplumber instead of guessing:

pythonCopy code
import pdfplumber

with pdfplumber.open("form.pdf") as pdf:
    pg = pdf.pages[0]
    for wd in pg.extract_words():  # each has x0, top, x1, bottom (TOP-left origin!)
        print(wd["text"], wd["x0"], wd["top"])
    for rc in pg.rects:  # small squares are likely checkboxes
        print("rect", rc["x0"], rc["top"], rc["x1"], rc["bottom"])

pdfplumber top is measured from the page top; pypdf rects are bottom-left, so convert: pdf_y = page_height - top. Place text just right of the matching label:

pythonCopy code
from pypdf import PdfReader, PdfWriter
from pypdf.annotations import FreeText

r = PdfReader("form.pdf")
w = PdfWriter()
w.append(r)
h = float(r.pages[0].mediabox.height)
top = 700  # pdfplumber 'top' of the label's row
w.add_annotation(
    page_number=0,
    annotation=FreeText(
        text="Smith",
        rect=(255, h - top - 14, 720, h - top),  # (x0, y0, x1, y1)
        font="Helvetica",
        font_size="10pt",
        font_color="000000",
        border_color=None,
        background_color=None,
    ),
)
w.write("filled.pdf")

Verify: re-open the output and re-read get_fields() values (fillable) or re-extract text (overlay) to confirm the values landed.

Page → image rendering (PyMuPDF)

PyMuPDF (imported as fitz, preinstalled) rasterizes pages — useful to inspect a PDF visually or to hand a page to an image-capable step. No external tools needed (poppler / pdf2image are absent; don't reach for them).

pythonCopy code
import fitz  # PyMuPDF

doc = fitz.open("in.pdf")
for i, page in enumerate(doc, 1):
    page.get_pixmap(dpi=150).save(f"page_{i}.png")  # higher dpi = sharper + larger

fitz also extracts text (page.get_text()) and can render a sub-region via page.get_pixmap(clip=fitz.Rect(x0, y0, x1, y1)). It does not OCR — a rendered scanned page is still just pixels (see Scanned PDFs above).