PowerPoint Presentation (.pptx)

A .pptx file is a ZIP archive of XML files. You can create, edit, and read them programmatically. Choose the right approach for the task:

Presentation Principles

• Every slide has one job. A slide that makes three points makes zero. Split ruthlessly.
• Text-only slides are forgettable. Every slide needs at least one visual element — chart, image, icon, data callout, or diagram.
• The deck must work without the speaker. Async decks (sent via email, read without a presenter) need more text and context than live-presentation decks.
• Visual hierarchy over bullet points. A large number + small label communicates faster than a sentence. A 2x2 grid communicates relationships better than a list.
• Commit to a visual direction and hold it. One font pair. One color palette. One layout style. Inconsistency signals lack of polish.
• AI slop is obvious. Cream backgrounds, accent stripes along card edges, Inter/Roboto with no rationale, blue CTA buttons, centered body text — these are trust killers. Avoid all of them.

Step 0: Before Creating

Ask the user:

1. What is the deck for? (investor pitch, all-hands, client presentation, technical review, sales demo)
2. Who is the audience? (technical, executive, external client, general team)
3. How many slides? Or: what content needs to be covered?
4. Brand constraints? (specific colors, fonts, logo to include)
5. Output format? (.pptx to edit further, or PDF to send)
6. Presenting live or sending async? (changes text density and speaker notes needs)

Creating with pptxgenjs (Node/TypeScript)

Setup

# pptxgenjs is often pre-installed — try require first
node -e "require('pptxgenjs')" 2>/dev/null && echo "installed" || npm install pptxgenjs

Basic Structure

const pptx = require("pptxgenjs");
const pres = new pptx();

// ALWAYS set layout before adding slides
pres.layout = "LAYOUT_16x9"; // 10" × 5.625" — standard widescreen

// Define theme colors (never use # prefix, never 8-digit hex)
const COLORS = {
  primary:    "1E3A5F",  // Deep navy
  accent:     "2E86AB",  // Electric blue
  light:      "F8F9FA",  // Near white
  dark:       "212529",  // Near black
  muted:      "6C757D",  // Gray
};

// Title slide
const titleSlide = pres.addSlide();
titleSlide.background = { color: COLORS.primary };
titleSlide.addText("Your Presentation Title", {
  x: 0.5, y: 1.8, w: 9, h: 1.2,
  fontSize: 40, bold: true, color: "FFFFFF",
  align: "left",
});
titleSlide.addText("Subtitle or date", {
  x: 0.5, y: 3.0, w: 9, h: 0.5,
  fontSize: 18, color: "A8C6E8",
  align: "left",
});

await pres.writeFile({ fileName: "presentation.pptx" });

Common Layout Patterns

Data callout slide (big numbers)

const slide = pres.addSlide();
slide.addText("Key Metrics", {
  x: 0.5, y: 0.3, w: 9, h: 0.6,
  fontSize: 28, bold: true, color: COLORS.dark
});

// Three metric blocks
const metrics = [
  { value: "810×", label: "Productivity increase" },
  { value: "40+",  label: "Features shipped" },
  { value: "3",    label: "Products launched" },
];

metrics.forEach((m, i) => {
  const x = 0.5 + i * 3.2;
  // Big number
  slide.addText(m.value, {
    x, y: 1.2, w: 2.8, h: 1.4,
    fontSize: 60, bold: true, color: COLORS.primary, align: "center"
  });
  // Label
  slide.addText(m.label, {
    x, y: 2.7, w: 2.8, h: 0.5,
    fontSize: 14, color: COLORS.muted, align: "center"
  });
});

Two-column slide

const slide = pres.addSlide();
// Left column — text
slide.addText("Problem", {
  x: 0.5, y: 0.3, w: 4.2, h: 0.5,
  fontSize: 24, bold: true, color: COLORS.dark
});
slide.addText("The current checkout flow has a 23% drop-off rate on mobile...", {
  x: 0.5, y: 1.0, w: 4.2, h: 3.5,
  fontSize: 14, color: COLORS.dark, valign: "top"
});
// Right column — image or chart
slide.addImage({ path: "chart.png", x: 5.2, y: 0.5, w: 4.3, h: 4.5 });

Critical gotchas

// ❌ WRONG — # prefix corrupts the file
color: "#FF0000"

// ✅ CORRECT — 6 hex chars, no #
color: "FF0000"

// ❌ WRONG — sharing option objects causes corruption
const shadow = { type: "outer", blur: 3, offset: 2, color: "000000" };
slide1.addShape(pptx.ShapeType.rect, { shadow }); // mutates shadow object
slide2.addShape(pptx.ShapeType.rect, { shadow }); // now uses corrupted values

// ✅ CORRECT — fresh object per call
const makeShadow = () => ({ type: "outer", blur: 3, offset: 2, color: "000000" });
slide1.addShape(pptx.ShapeType.rect, { shadow: makeShadow() });
slide2.addShape(pptx.ShapeType.rect, { shadow: makeShadow() });

// ❌ WRONG — shadow offset must be >= 0
shadow: { offset: -2 }  // corrupts file

// ✅ CORRECT
shadow: { offset: 2 }

Creating with python-pptx

from pptx import Presentation
from pptx.util import Inches, Pt, Emu
from pptx.dml.color import RGBColor
from pptx.enum.text import PP_ALIGN

prs = Presentation()
prs.slide_width  = Inches(13.33)
prs.slide_height = Inches(7.5)

# Add a slide using blank layout
blank_layout = prs.slide_layouts[6]
slide = prs.slides.add_slide(blank_layout)

# Add title text box
txBox = slide.shapes.add_textbox(Inches(0.5), Inches(0.3), Inches(12), Inches(1))
tf = txBox.text_frame
tf.word_wrap = True
p = tf.add_paragraph()
p.text = "Slide Title"
p.font.bold = True
p.font.size = Pt(36)
p.font.color.rgb = RGBColor(0x1E, 0x3A, 0x5F)
p.alignment = PP_ALIGN.LEFT

prs.save("presentation.pptx")

Editing an Existing Deck

# Unzip to inspect/edit
mkdir deck_unpacked && cp deck.pptx deck.zip
unzip deck.zip -d deck_unpacked/

# Slides are at: deck_unpacked/ppt/slides/slide1.xml, slide2.xml, etc.
# Edit XML directly for text replacement, color changes, etc.

# Repack
cd deck_unpacked && zip -r ../deck_edited.pptx . && cd ..

For simple text replacement across all slides:

from pptx import Presentation

prs = Presentation("template.pptx")
for slide in prs.slides:
    for shape in slide.shapes:
        if shape.has_text_frame:
            for para in shape.text_frame.paragraphs:
                for run in para.runs:
                    run.text = run.text.replace("{{COMPANY}}", "Acme Corp")
prs.save("output.pptx")

Reading / Extracting Content

# Extract all text, slide by slide
markitdown deck.pptx

# Check for placeholder text (leftover template text)
markitdown deck.pptx | grep -iE "\bx{3,}\b|lorem|ipsum|\bTODO|\[insert"

from pptx import Presentation

prs = Presentation("deck.pptx")
for i, slide in enumerate(prs.slides, 1):
    print(f"\n--- Slide {i} ---")
    for shape in slide.shapes:
        if shape.has_text_frame:
            print(shape.text_frame.text)

Design Standards

Color palettes (use one, stay consistent)

Typography

Safe fonts (render correctly in both PowerPoint and LibreOffice): Arial, Calibri, Cambria, Times New Roman, Courier New

What to never do

• ❌ Accent lines or stripes under titles (AI slop signature)
• ❌ Decorative color bars spanning slide width
• ❌ Centered body text (left-align everything except titles)
• ❌ Cream/beige background when not specified — use white
• ❌ Text-only slides — always add a visual element
• ❌ Same layout repeated on every slide
• ❌ # prefix in color values (pptxgenjs)
• ❌ Shared option objects across add calls (pptxgenjs)

QA Before Delivering

# 1. Content check — read all text
markitdown output.pptx

# 2. Check for leftover placeholder text
markitdown output.pptx | grep -iE "\bx{3,}\b|lorem|ipsum|TODO|\[insert"

# 3. Convert to PDF for visual check
libreoffice --headless --convert-to pdf output.pptx

# 4. Visual inspection checklist:

Visual QA checklist (check every slide):

• No text overflowing its box or the slide edge
• No overlapping elements
• Minimum 0.5" margin from all slide edges
• Consistent gaps between content blocks (0.3" or 0.5" — pick one)
• No low-contrast text (light on light, dark on dark)
• No leftover template placeholder text
• Speaker notes added for any slide that needs explanation

Definition of Done — PPTX

• Deck purpose, audience, and slide count confirmed before starting
• Layout set before first slide added (pres.layout = "LAYOUT_16x9")
• Color palette defined — no # prefix, no 8-digit hex
• One font pair used consistently throughout
• Every slide has at least one visual element (no text-only slides)
• No accent stripes, decorative bars, or cream backgrounds
• No AI slop patterns (see list above)
• Content QA run: markitdown output.pptx
• Placeholder text check: no leftover lorem, TODO, [insert]
• Visual QA: every slide inspected for overflow, overlap, contrast
• Speaker notes added where needed
• File opens without errors in PowerPoint / LibreOffice