Slide Making Skill

PptxGenJS Slide Making Skill

This skill teaches how to generate native .pptx slides using PptxGenJS (JavaScript).

PptxGenJS Reference

Read pptxgenjs.md for the complete PptxGenJS API reference, including:

• Setup & basic structure
• Text & formatting
• Lists & bullets
• Shapes & shadows
• Images & icons
• Slide backgrounds
• Tables & charts

Font Rules

Font Family Standards

fontFace: "Microsoft YaHei"  // Chinese text
fontFace: "Arial"            // English text (or approved alternative)

Use system-safe fonts for cross-platform compatibility. Header/body can use different fonts (e.g., Georgia + Calibri).

No Bold for Body Text

Plain body text and caption/legend text must NOT use bold.

• Body paragraphs, descriptions → normal weight
• Captions, legends, footnotes → normal weight
• Reserve bold for titles and headings only

// ✅ Correct
slide.addText("Main Title", { bold: true, fontSize: 36, fontFace: "Arial" });
slide.addText("Body text here.", { bold: false, fontSize: 14, fontFace: "Arial" });

// ❌ Wrong
slide.addText("Body text here.", { bold: true, fontSize: 14 });

Color Palette Rules (MANDATORY)

Strict Palette Adherence

Use ONLY the provided color palette. Do NOT create or modify colors.

• All colors must come from the user-provided palette
• Do NOT use colors outside the palette
• Do NOT modify palette colors (brightness, saturation, mixing)
• Only exception: Add transparency using the transparency property (0-100)

// ✅ Correct: Using palette colors
slide.addShape(pres.shapes.RECTANGLE, { fill: { color: theme.primary } });
slide.addText("Title", { color: theme.accent });

// ❌ Wrong: Colors outside palette
slide.addShape(pres.shapes.RECTANGLE, { fill: { color: "1a1a2e" } });

No Gradients

Gradients are prohibited. Use solid colors only.

// ✅ Correct: Solid colors
slide.background = { color: theme.bg };

// ✅ Correct: Solid + transparency for overlay
slide.addShape(pres.shapes.RECTANGLE, { fill: { color: theme.accent, transparency: 50 } });

No Animations

Animations and transitions are prohibited. All slides must be static.

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"
});

Theme Object Contract (MANDATORY)

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

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

Subagent Output Format

Each subagent outputs 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",  // English text uses Arial
    color: theme.primary, bold: true, align: "center"
  });

  return slide;
}

// Standalone preview - use slide-specific filename (slide-XX-preview.pptx)
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);
  // Replace XX with actual slide index (01, 02, etc.) to avoid conflicts
  pres.writeFile({ fileName: "slide-01-preview.pptx" });
}

module.exports = { createSlide, slideConfig };

Critical Pitfalls

NEVER use async/await in createSlide()

// ❌ WRONG - compile.js won't await
async function createSlide(pres, theme) { ... }

// ✅ CORRECT
function createSlide(pres, theme) { ... }

NEVER use "#" with hex colors

color: "FF0000"      // ✅ CORRECT
color: "#FF0000"     // ❌ CORRUPTS FILE

NEVER encode opacity in hex strings

shadow: { color: "00000020" }              // ❌ CORRUPTS FILE
shadow: { color: "000000", opacity: 0.12 } // ✅ CORRECT

Prevent text wrapping in titles

// ✅ Use fit:'shrink' for long titles
slide.addText("Long Title Here", {
  x: 0.5, y: 2, w: 9, h: 1,
  fontSize: 48, fit: "shrink"
});

Quick Reference

• Dimensions: 10" × 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"

QA (Required)

Assume there are problems. Your job is to find them.

Your first render is almost never correct. Approach QA as a bug hunt, not a confirmation step. If you found zero issues on first inspection, you weren't looking hard enough.

Content QA

python -m markitdown slide-XX-preview.pptx

Check for missing content, typos, wrong order.

Check for leftover placeholder text:

python -m markitdown slide-XX-preview.pptx | grep -iE "xxxx|lorem|ipsum|placeholder"

If grep returns results, fix them before declaring success.

Verification Loop

1. Generate slide → Extract text with python -m markitdown slide-XX-preview.pptx → Review content
2. List issues found (if none found, look again more critically)
3. Fix issues
4. Re-verify — one fix often creates another problem
5. Repeat until verification reveals no new issues

Do not declare success until you've completed at least one fix-and-verify cycle.