ninehills/pptx-generator

PPTX Generator & Editor

Overview

This skill handles all PowerPoint tasks: reading/analyzing existing presentations, editing template-based decks via XML manipulation, and creating presentations from scratch using PptxGenJS. It includes a complete design system (color palettes, fonts, style recipes) and detailed guidance for every slide type.

Quick Reference

| Task | Approach | |------|----------| | Read/analyze content | python -m markitdown presentation.pptx | | Edit or create from template | See Editing Presentations | | Create from scratch | See Creating from Scratch below |

| Item | Value | |------|-------| | Dimensions | 10" x 5.625" (LAYOUT_16x9) | | Colors | 6-char hex without # (e.g., "FF0000") | | English font | Arial (default), or approved alternatives | | Chinese font | Microsoft YaHei | | Page badge position | x: 9.3", y: 5.1" | | Theme keys | primary, secondary, accent, light, bg | | Shapes | RECTANGLE, OVAL, LINE, ROUNDED_RECTANGLE | | Charts | BAR, LINE, PIE, DOUGHNUT, SCATTER, BUBBLE, RADAR |

Reference Files

| File | Contents | |------|----------| | slide-types.md | 5 slide page types (Cover, TOC, Section Divider, Content, Summary) + additional layout patterns | | design-system.md | Color palettes, font reference, style recipes (Sharp/Soft/Rounded/Pill), typography & spacing | | editing.md | Template-based editing workflow, XML manipulation, formatting rules, common pitfalls | | pitfalls.md | QA process, common mistakes, critical PptxGenJS pitfalls | | pptxgenjs.md | Complete PptxGenJS API reference |

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Reading Content

# Text extraction
python -m markitdown presentation.pptx

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Creating from Scratch — Workflow

Use when no template or reference presentation is available.

Step 1: Research & Requirements

Search to understand user requirements — topic, audience, purpose, tone, content depth.

Step 2: Select Color Palette & Fonts

Use the Color Palette Reference to select a palette matching the topic and audience. Use the Font Reference to choose a font pairing.

Step 3: Select Design Style

Use the Style Recipes to choose a visual style (Sharp, Soft, Rounded, or Pill) matching the presentation tone.

Step 4: Plan Slide Outline

Classify every slide as exactly one of the 5 page types. Plan the content and layout for each slide. Ensure visual variety — do NOT repeat the same layout across slides.

Step 5: Generate Slide JS Files

Create one JS file per slide in slides/ directory. Each file must export a synchronous createSlide(pres, theme) function. Follow the Slide Output Format and the type-specific guidance in slide-types.md. Generate up to 5 slides concurrently using subagents if available.

Tell each subagent:

1. File naming: slides/slide-01.js, slides/slide-02.js, etc.
2. Images go in: slides/imgs/
3. Final PPTX goes in: slides/output/
4. Dimensions: 10" x 5.625" (LAYOUT_16x9)
5. Fonts: Chinese = Microsoft YaHei, English = Arial (or approved alternative)
6. Colors: 6-char hex without # (e.g. "FF0000")
7. Must use the theme object contract (see Theme Object Contract)
8. Must follow the PptxGenJS API reference

Step 6: Compile into Final PPTX

Create slides/compile.js to combine all slide modules:

// slides/compile.js
const pptxgen = require('pptxgenjs');
const pres = new pptxgen();
pres.layout = 'LAYOUT_16x9';

const theme = {
  primary: "22223b",    // dark color for backgrounds/text
  secondary: "4a4e69",  // secondary accent
  accent: "9a8c98",     // highlight color
  light: "c9ada7",      // light accent
  bg: "f2e9e4"          // background color
};

for (let i = 1; i <= 12; i++) {  // adjust count as needed
  const num = String(i).padStart(2, '0');
  const slideModule = require(`./slide-${num}.js`);
  slideModule.createSlide(pres, theme);
}

pres.writeFile({ fileName: './output/presentation.pptx' });

Run with: cd slides && node compile.js

Step 7: QA (Required)

See QA Process.

Output Structure

slides/
├── slide-01.js          # Slide modules
├── slide-02.js
├── ...
├── imgs/                # Images used in slides
└── output/              # Final artifacts
    └── presentation.pptx

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Slide Output Format

Each slide is a complete, runnable JS file:

// slide-01.js
const pptxgen = require("pptxgenjs");

const slideConfig = {
  type: 'cover',
  index: 1,
  title: 'Presentation Title'
};

// MUST be synchronous (not async)
function createSlide(pres, theme) {
  const slide = pres.addSlide();
  slide.background = { color: theme.bg };

  slide.addText(slideConfig.title, {
    x: 0.5, y: 2, w: 9, h: 1.2,
    fontSize: 48, fontFace: "Arial",
    color: theme.primary, bold: true, align: "center"
  });

  return slide;
}

// Standalone preview - use slide-specific filename
if (require.main === module) {
  const pres = new pptxgen();
  pres.layout = 'LAYOUT_16x9';
  const theme = {
    primary: "22223b",
    secondary: "4a4e69",
    accent: "9a8c98",
    light: "c9ada7",
    bg: "f2e9e4"
  };
  createSlide(pres, theme);
  pres.writeFile({ fileName: "slide-01-preview.pptx" });
}

module.exports = { createSlide, slideConfig };

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Theme Object Contract (MANDATORY)

The compile script passes a theme object with these exact keys:

| Key | Purpose | Example | |-----|---------|---------| | theme.primary | Darkest color, titles | "22223b" | | theme.secondary | Dark accent, body text | "4a4e69" | | theme.accent | Mid-tone accent | "9a8c98" | | theme.light | Light accent | "c9ada7" | | theme.bg | Background color | "f2e9e4" |

NEVER use other key names like background, text, muted, darkest, lightest.

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Page Number Badge (REQUIRED)

All slides except Cover Page MUST include a page number badge in the bottom-right corner.

• Position: x: 9.3", y: 5.1"
• Show current number only (e.g. 3 or 03), NOT "3/12"
• Use palette colors, keep subtle

Circle Badge (Default)

slide.addShape(pres.shapes.OVAL, {
  x: 9.3, y: 5.1, w: 0.4, h: 0.4,
  fill: { color: theme.accent }
});
slide.addText("3", {
  x: 9.3, y: 5.1, w: 0.4, h: 0.4,
  fontSize: 12, fontFace: "Arial",
  color: "FFFFFF", bold: true,
  align: "center", valign: "middle"
});

Pill Badge

slide.addShape(pres.shapes.ROUNDED_RECTANGLE, {
  x: 9.1, y: 5.15, w: 0.6, h: 0.35,
  fill: { color: theme.accent },
  rectRadius: 0.15
});
slide.addText("03", {
  x: 9.1, y: 5.15, w: 0.6, h: 0.35,
  fontSize: 11, fontFace: "Arial",
  color: "FFFFFF", bold: true,
  align: "center", valign: "middle"
});

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Dependencies

• pip install "markitdown[pptx]" — text extraction
• npm install -g pptxgenjs — creating from scratch
• npm install -g react-icons react react-dom sharp — icons (optional)