Pptx

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

pythonCopy code
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.

pythonCopy code
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:

pythonCopy code
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.

pythonCopy code
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.

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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

pythonCopy code
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:

pythonCopy code
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:

pythonCopy code
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):

pythonCopy code
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.