pptx

Work with PowerPoint .pptx files using python-pptx (preinstalled). A .pptx

is a ZIP of XML parts; python-pptx handles the structure so you rarely touch XML.

Drop to raw OOXML only for the few things the library can't express (see Advanced).

Use exec with complete Python source (language: python). Keep asset creation,

deck generation, reopening, and structural verification in one call when

possible; later calls can revise the same relative filename. Follow the turn's

User workspace instructions for locating inputs, output boundaries, and

presenting the finished deck.

Mental model

• A presentation has slides; each slide is built from a layout; layouts

live on slide masters. Layouts define placeholders (title, body,

picture, etc.) by idx and type.

• A slide holds shapes: placeholders, text boxes, pictures, tables, charts.
• Shapes with text expose .text_frame → .paragraphs → .runs. A run is the

unit that carries formatting (font, size, bold, color).

• Units are EMU. Use the helpers: from pptx.util import Inches, Pt, Emu.

Read / extract

from pptx import Presentation

prs = Presentation("deck.pptx")
print(len(prs.slides), prs.slide_width, prs.slide_height)  # EMU dims

for i, slide in enumerate(prs.slides, 1):
    print(f"--- slide {i} (layout: {slide.slide_layout.name}) ---")
    for shape in slide.shapes:
        if shape.has_text_frame:
            print(shape.text_frame.text)  # \n-joined paragraphs
        elif shape.has_table:
            for row in shape.table.rows:
                print([c.text for c in row.cells])
    if slide.has_notes_slide:
        notes = slide.notes_slide.notes_text_frame.text
        if notes:
            print("NOTES:", notes)

Iterate slide.placeholders to see placeholder idx / placeholder_format.type.

For a fast text-only dump, just collect shape.text_frame.text across slides.

Create from an outline

List the layouts first — indices vary by template. With the default template,

layout 0 = Title, 1 = Title+Content, 5 = Title Only, 6 = Blank.

from pptx import Presentation
from pptx.util import Inches, Pt

prs = Presentation()  # or Presentation("template.pptx") to inherit a theme
for idx, lay in enumerate(prs.slide_layouts):
    print(idx, lay.name, [(p.placeholder_format.idx, p.name) for p in lay.placeholders])

# Title slide
s = prs.slides.add_slide(prs.slide_layouts[0])
s.shapes.title.text = "My Deck"
s.placeholders[1].text = "Subtitle"  # idx from the listing above

# Title + bullets
s = prs.slides.add_slide(prs.slide_layouts[1])
s.shapes.title.text = "Agenda"
tf = s.placeholders[1].text_frame
tf.text = "First point"  # first paragraph
for line, lvl in [("Second", 0), ("Sub-point", 1)]:
    p = tf.add_paragraph()
    p.text = line
    p.level = lvl

prs.save("out.pptx")

Always set text via placeholders/shapes — never hand-write bullet glyphs (•);

indentation/bullets come from the layout via paragraph.level.

Add a free text box or picture on any slide:

tb = s.shapes.add_textbox(Inches(1), Inches(1), Inches(8), Inches(1))
r = tb.text_frame.paragraphs[0].add_run()
r.text = "Hi"
r.font.size = Pt(28)
r.font.bold = True
s.shapes.add_picture("logo.png", Inches(0.5), Inches(0.5), height=Inches(1))  # omit w to keep ratio

Edit existing

Edit at the run level to preserve a run's formatting; rewriting

text_frame.text collapses to one run and drops inline formatting.

for slide in prs.slides:
    for shape in slide.shapes:
        if not shape.has_text_frame:
            continue
        for para in shape.text_frame.paragraphs:
            for run in para.runs:
                if "{{NAME}}" in run.text:
                    run.text = run.text.replace("{{NAME}}", "Frank")

To delete a shape/placeholder: sp = shape._element; sp.getparent().remove(sp).

If the template has more slots than your data, remove the extra shapes entirely

rather than leaving empty placeholders.

Replace an image in place (keep size/position)

python-pptx has no direct setter; swap the bytes of the related image part. Read

the picture's r:embed rId off its <a:blip>, then overwrite the part's blob.

The replacement bytes must use the same image encoding as the original part

(for example PNG for PNG). A different encoding also requires a new correctly

typed media part and relationship; changing _blob alone would leave invalid

content-type metadata.

from pptx.oxml.ns import qn

for shape in slide.shapes:
    if shape.shape_type == 13:  # MSO_SHAPE_TYPE.PICTURE
        blip = shape._element.find(".//" + qn("a:blip"))
        rid = blip.get(qn("r:embed"))
        with open("new.png", "rb") as f:
            shape.part.related_part(rid)._blob = f.read()

Tables and charts

from pptx.util import Inches

tbl = s.shapes.add_table(
    rows=2, cols=2, left=Inches(1), top=Inches(1), width=Inches(6), height=Inches(2)
).table
tbl.cell(0, 0).text = "Header"

from pptx.chart.data import CategoryChartData
from pptx.enum.chart import XL_CHART_TYPE

cd = CategoryChartData()
cd.categories = ["Q1", "Q2", "Q3"]
cd.add_series("Sales", (4.5, 5.5, 6.2))
s.shapes.add_chart(XL_CHART_TYPE.COLUMN_CLUSTERED, Inches(1), Inches(1), Inches(8), Inches(4.5), cd)

Design (only when the user wants a polished deck, not a data dump)

• Pick a topic-specific palette and one accent; don't default to generic blue.

One color should dominate. Dark title/closing slides, light content slides.

• Vary layouts across slides (two-column, stat callout, quote, section divider) —

repeating one bullet layout reads as low-effort. Give most slides a visual

element (image/chart/shape), not just title + bullets.

• Type scale: title 36-44pt, section headers 20-24pt, body 14-16pt. Bold headers

and inline labels. Left-align body; center only titles. Keep >=0.5in margins.

• Set text_frame.word_wrap = True and watch for overflow; long replacement text

may spill. After rendering (see Export), inspect the images critically — assume

there are overlap/overflow/contrast bugs and fix them before declaring done.

Export to PDF / images (optional, needs LibreOffice)

Do the availability check and conversion through Python source sent to exec;

this works with pip, source, Docker, and Windows deployments without

assuming POSIX shell syntax or printing a physical working directory:

from pathlib import Path
import shutil
import subprocess

deck = Path("out.pptx")
soffice = shutil.which("soffice")
if not soffice:
    print("soffice not available — cannot export")
else:
    subprocess.run([soffice, "--headless", "--convert-to", "pdf", str(deck)], check=True)
    pdftoppm = shutil.which("pdftoppm")
    if pdftoppm:
        subprocess.run([pdftoppm, "-jpeg", "-r", "150", "out.pdf", "slide"], check=True)
        print(*sorted(str(path) for path in Path(".").glob("slide-*.jpg")), sep="\n")

If an image-reading tool is actually mounted, use it to inspect every rendered

slide. workspace_present only presents a file to the user; it does not let you

see the rendered pixels. If no image-reading tool is available, perform the

structural checks below and say that visual inspection was unavailable rather

than claiming you inspected the slides. Re-run conversion after every edit — the

PDF won't reflect a changed .pptx otherwise. If soffice (or pdftoppm) is

absent, say so and skip export; do not install it during the task.

.ppt → .pptx

Legacy .ppt is a different binary format — python-pptx cannot open it. Convert

first if soffice exists, else tell the user it can't be processed. Route this

through exec with language: python, not an implicit shell:

import shutil
import subprocess

soffice = shutil.which("soffice")
if not soffice:
    print("need soffice for .ppt")
else:
    subprocess.run([soffice, "--headless", "--convert-to", "pptx", "old.ppt"], check=True)

Advanced: raw OOXML (last resort)

Use only for things python-pptx can't do (e.g. exact-fidelity slide duplication,

gradient fills, theme color edits, untyped XML elements). python-pptx already

exposes each shape's XML via shape._element (lxml) — prefer surgical lxml edits

there over a full unzip when you can. For part-level surgery, unzip → edit the

XML part → re-zip with stdlib zipfile.

Package map: slide order in ppt/presentation.xml <p:sldIdLst>; slides in

ppt/slides/slideN.xml with rels in ppt/slides/_rels/slideN.xml.rels; layouts/

masters under ppt/slideLayouts, ppt/slideMasters; media in ppt/media/;

part types in [Content_Types].xml.

Critical invariants if you add/edit parts by hand — break one and PowerPoint

reports the file as corrupt:

• Every new part is declared in [Content_Types].xml (an <Override> for slides;

a <Default> per media extension like png/jpeg).

• Every cross-part link goes through a _rels/*.rels <Relationship>; r:id refs

in XML must resolve. Adding a slide means: write the part + its .rels, add the

content-type override, add a <Relationship> in presentation.xml.rels, and a

<p:sldId> in <p:sldIdLst>.

• IDs must be unique: <p:sldId> ids, and shape ids (<p:cNvPr id=...>) within a

slide. sldLayoutId/sldMasterId are globally unique.

• Whitespace: any <a:t> with leading/trailing spaces needs xml:space="preserve".
• Parse/serialize with lxml or defusedxml; never naive string munging that

mangles namespaces or pretty-prints into text nodes.

Minimal text edit by zip surgery (zip members can't be overwritten in place —

rebuild the archive, swapping the one part):

import zipfile

target = "ppt/slides/slide1.xml"
with zipfile.ZipFile("in.pptx") as zin:
    xml = zin.read(target).decode().replace("Old title", "New title")
    with zipfile.ZipFile("out.pptx", "w", zipfile.ZIP_DEFLATED) as zout:
        for item in zin.namelist():
            zout.writestr(item, xml.encode() if item == target else zin.read(item))

Verify before done

Reopen the output with Presentation("out.pptx") and assert slide count / key

text — a clean reopen catches most corruption. For decks meant to look good,

also export and visually inspect (above). Check templates for leftover

placeholder text (xxxx, lorem, [insert ...]) and fix before declaring done.