gyan/pptx

Create and edit PowerPoint decks (pptx) using PptxGenJS.

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PptxGenJS Tutorial

Name: gyan/pptx
Rating: 0.915 (1 reviews)
Author: gyan

Setup & Basic Structure

const pptxgen = require("pptxgenjs");

let pres = new pptxgen();
pres.layout = 'LAYOUT_16x9';  // or 'LAYOUT_16x10', 'LAYOUT_4x3', 'LAYOUT_WIDE'
pres.author = 'Your Name';
pres.title = 'Presentation Title';

let slide = pres.addSlide();
slide.addText("Hello World!", { x: 0.5, y: 0.5, fontSize: 36, color: "363636" });

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

Layout Dimensions

Slide dimensions (coordinates in inches):

LAYOUT_16x9: 10" × 5.625" (default)
LAYOUT_16x10: 10" × 6.25"
LAYOUT_4x3: 10" × 7.5"
LAYOUT_WIDE: 13.3" × 7.5"

Text & Formatting

// Basic text
slide.addText("Simple Text", {
  x: 1, y: 1, w: 8, h: 2, fontSize: 24, fontFace: "Arial",
  color: "363636", bold: true, align: "center", valign: "middle"
});

// Character spacing (use charSpacing, not letterSpacing which is silently ignored)
slide.addText("SPACED TEXT", { x: 1, y: 1, w: 8, h: 1, charSpacing: 6 });

// Rich text arrays
slide.addText([
  { text: "Bold ", options: { bold: true } },
  { text: "Italic ", options: { italic: true } }
], { x: 1, y: 3, w: 8, h: 1 });

// Multi-line text (requires breakLine: true)
slide.addText([
  { text: "Line 1", options: { breakLine: true } },
  { text: "Line 2", options: { breakLine: true } },
  { text: "Line 3" }  // Last item doesn't need breakLine
], { x: 0.5, y: 0.5, w: 8, h: 2 });

// Text box margin (internal padding)
slide.addText("Title", {
  x: 0.5, y: 0.3, w: 9, h: 0.6,
  margin: 0  // Use 0 when aligning text with other elements like shapes or icons
});

Tip: Text boxes have internal margin by default. Set margin: 0 when you need text to align precisely with shapes, lines, or icons at the same x-position.

Lists & Bullets

// ✅ CORRECT: Multiple bullets
slide.addText([
  { text: "First item", options: { bullet: true, breakLine: true } },
  { text: "Second item", options: { bullet: true, breakLine: true } },
  { text: "Third item", options: { bullet: true } }
], { x: 0.5, y: 0.5, w: 8, h: 3 });

// ❌ WRONG: Never use unicode bullets
slide.addText("• First item", { ... });  // Creates double bullets

// Sub-items and numbered lists
{ text: "Sub-item", options: { bullet: true, indentLevel: 1 } }
{ text: "First", options: { bullet: { type: "number" }, breakLine: true } }

Shapes

slide.addShape(pres.shapes.RECTANGLE, {
  x: 0.5, y: 0.8, w: 1.5, h: 3.0,
  fill: { color: "FF0000" }, line: { color: "000000", width: 2 }
});

slide.addShape(pres.shapes.OVAL, { x: 4, y: 1, w: 2, h: 2, fill: { color: "0000FF" } });

slide.addShape(pres.shapes.LINE, {
  x: 1, y: 3, w: 5, h: 0, line: { color: "FF0000", width: 3, dashType: "dash" }
});

// With transparency
slide.addShape(pres.shapes.RECTANGLE, {
  x: 1, y: 1, w: 3, h: 2,
  fill: { color: "0088CC", transparency: 50 }
});

// Rounded rectangle (rectRadius only works with ROUNDED_RECTANGLE, not RECTANGLE)
// ⚠️ Don't pair with rectangular accent overlays — they won't cover rounded corners. Use RECTANGLE instead.
slide.addShape(pres.shapes.ROUNDED_RECTANGLE, {
  x: 1, y: 1, w: 3, h: 2,
  fill: { color: "FFFFFF" }, rectRadius: 0.1
});

// With shadow
slide.addShape(pres.shapes.RECTANGLE, {
  x: 1, y: 1, w: 3, h: 2,
  fill: { color: "FFFFFF" },
  shadow: { type: "outer", color: "000000", blur: 6, offset: 2, angle: 135, opacity: 0.15 }
});

Shadow options:

Property	Type	Range	Notes
`type`	string	`"outer"`, `"inner"`
`color`	string	6-char hex (e.g. `"000000"`)	No `#` prefix, no 8-char hex — see Common Pitfalls
`blur`	number	0-100 pt
`offset`	number	0-200 pt	Must be non-negative — negative values corrupt the file
`angle`	number	0-359 degrees	Direction the shadow falls (135 = bottom-right, 270 = upward)
`opacity`	number	0.0-1.0	Use this for transparency, never encode in color string

To cast a shadow upward (e.g. on a footer bar), use angle: 270 with a positive offset — do not use a negative offset.

Note: Gradient fills are not natively supported. Use a gradient image as a background instead.

Images

Image Sources

// From file path
slide.addImage({ path: "images/chart.png", x: 1, y: 1, w: 5, h: 3 });

// From URL
slide.addImage({ path: "https://example.com/image.jpg", x: 1, y: 1, w: 5, h: 3 });

// From base64 (faster, no file I/O)
slide.addImage({ data: "image/png;base64,iVBORw0KGgo...", x: 1, y: 1, w: 5, h: 3 });

Image Options

slide.addImage({
  path: "image.png",
  x: 1, y: 1, w: 5, h: 3,
  rotate: 45,              // 0-359 degrees
  rounding: true,          // Circular crop
  transparency: 50,        // 0-100
  flipH: true,             // Horizontal flip
  flipV: false,            // Vertical flip
  altText: "Description",  // Accessibility
  hyperlink: { url: "https://example.com" }
});

Image Sizing Modes

// Contain - fit inside, preserve ratio
{ sizing: { type: 'contain', w: 4, h: 3 } }

// Cover - fill area, preserve ratio (may crop)
{ sizing: { type: 'cover', w: 4, h: 3 } }

// Crop - cut specific portion
{ sizing: { type: 'crop', x: 0.5, y: 0.5, w: 2, h: 2 } }

Calculate Dimensions (preserve aspect ratio)

const origWidth = 1978, origHeight = 923, maxHeight = 3.0;
const calcWidth = maxHeight * (origWidth / origHeight);
const centerX = (10 - calcWidth) / 2;

slide.addImage({ path: "image.png", x: centerX, y: 1.2, w: calcWidth, h: maxHeight });

Supported Formats

Standard: PNG, JPG, GIF (animated GIFs work in Microsoft 365)
SVG: Works in modern PowerPoint/Microsoft 365

Icons

Use react-icons to generate SVG icons, then rasterize to PNG for universal compatibility.

Setup

const React = require("react");
const ReactDOMServer = require("react-dom/server");
const sharp = require("sharp");
const { FaCheckCircle, FaChartLine } = require("react-icons/fa");

function renderIconSvg(IconComponent, color = "#000000", size = 256) {
  return ReactDOMServer.renderToStaticMarkup(
    React.createElement(IconComponent, { color, size: String(size) })
  );
}

async function iconToBase64Png(IconComponent, color, size = 256) {
  const svg = renderIconSvg(IconComponent, color, size);
  const pngBuffer = await sharp(Buffer.from(svg)).png().toBuffer();
  return "image/png;base64," + pngBuffer.toString("base64");
}

Add Icon to Slide

const iconData = await iconToBase64Png(FaCheckCircle, "#4472C4", 256);

slide.addImage({
  data: iconData,
  x: 1, y: 1, w: 0.5, h: 0.5  // Size in inches
});

Note: Use size 256 or higher for crisp icons. The size parameter controls the rasterization resolution, not the display size on the slide (which is set by w and h in inches).

Icon Libraries

Install: npm install -g react-icons react react-dom sharp

Popular icon sets in react-icons:

react-icons/fa - Font Awesome
react-icons/md - Material Design
react-icons/hi - Heroicons
react-icons/bi - Bootstrap Icons

Slide Backgrounds

// Solid color
slide.background = { color: "F1F1F1" };

// Color with transparency
slide.background = { color: "FF3399", transparency: 50 };

// Image from URL
slide.background = { path: "https://example.com/bg.jpg" };

// Image from base64
slide.background = { data: "image/png;base64,iVBORw0KGgo..." };

Tables

slide.addTable([
  ["Header 1", "Header 2"],
  ["Cell 1", "Cell 2"]
], {
  x: 1, y: 1, w: 8, h: 2,
  border: { pt: 1, color: "999999" }, fill: { color: "F1F1F1" }
});

// Advanced with merged cells
let tableData = [
  [{ text: "Header", options: { fill: { color: "6699CC" }, color: "FFFFFF", bold: true } }, "Cell"],
  [{ text: "Merged", options: { colspan: 2 } }]
];
slide.addTable(tableData, { x: 1, y: 3.5, w: 8, colW: [4, 4] });

Charts

// Bar chart
slide.addChart(pres.charts.BAR, [{
  name: "Sales", labels: ["Q1", "Q2", "Q3", "Q4"], values: [4500, 5500, 6200, 7100]
}], {
  x: 0.5, y: 0.6, w: 6, h: 3, barDir: 'col',
  showTitle: true, title: 'Quarterly Sales'
});

// Line chart
slide.addChart(pres.charts.LINE, [{
  name: "Temp", labels: ["Jan", "Feb", "Mar"], values: [32, 35, 42]
}], { x: 0.5, y: 4, w: 6, h: 3, lineSize: 3, lineSmooth: true });

// Pie chart
slide.addChart(pres.charts.PIE, [{
  name: "Share", labels: ["A", "B", "Other"], values: [35, 45, 20]
}], { x: 7, y: 1, w: 5, h: 4, showPercent: true });

Better-Looking Charts

Default charts look dated. Apply these options for a modern, clean appearance:

slide.addChart(pres.charts.BAR, chartData, {
  x: 0.5, y: 1, w: 9, h: 4, barDir: "col",

  // Custom colors (match your presentation palette)
  chartColors: ["0D9488", "14B8A6", "5EEAD4"],

  // Clean background
  chartArea: { fill: { color: "FFFFFF" }, roundedCorners: true },

  // Muted axis labels
  catAxisLabelColor: "64748B",
  valAxisLabelColor: "64748B",

  // Subtle grid (value axis only)
  valGridLine: { color: "E2E8F0", size: 0.5 },
  catGridLine: { style: "none" },

  // Data labels on bars
  showValue: true,
  dataLabelPosition: "outEnd",
  dataLabelColor: "1E293B",

  // Hide legend for single series
  showLegend: false,
});

Key styling options:

chartColors: [...] - hex colors for series/segments
chartArea: { fill, border, roundedCorners } - chart background
catGridLine/valGridLine: { color, style, size } - grid lines (style: "none" to hide)
lineSmooth: true - curved lines (line charts)
legendPos: "r" - legend position: "b", "t", "l", "r", "tr"

Slide Masters

pres.defineSlideMaster({
  title: 'TITLE_SLIDE', background: { color: '283A5E' },
  objects: [{
    placeholder: { options: { name: 'title', type: 'title', x: 1, y: 2, w: 8, h: 2 } }
  }]
});

let titleSlide = pres.addSlide({ masterName: "TITLE_SLIDE" });
titleSlide.addText("My Title", { placeholder: "title" });

Common Pitfalls

⚠️ These issues cause file corruption, visual bugs, or broken output. Avoid them.

NEVER use "#" with hex colors - causes file corruption

color: "FF0000"      // ✅ CORRECT
color: "#FF0000"     // ❌ WRONG

NEVER encode opacity in hex color strings - 8-char colors (e.g., "00000020") corrupt the file. Use the opacity property instead.

shadow: { type: "outer", blur: 6, offset: 2, color: "00000020" }          // ❌ CORRUPTS FILE
shadow: { type: "outer", blur: 6, offset: 2, color: "000000", opacity: 0.12 }  // ✅ CORRECT

Use bullet: true - NEVER unicode symbols like "•" (creates double bullets)
Use breakLine: true between array items or text runs together
Avoid lineSpacing with bullets - causes excessive gaps; use paraSpaceAfter instead
Each presentation needs fresh instance - don't reuse pptxgen() objects

NEVER reuse option objects across calls - PptxGenJS mutates objects in-place (e.g. converting shadow values to EMU). Sharing one object between multiple calls corrupts the second shape.

const shadow = { type: "outer", blur: 6, offset: 2, color: "000000", opacity: 0.15 };
slide.addShape(pres.shapes.RECTANGLE, { shadow, ... });  // ❌ second call gets already-converted values
slide.addShape(pres.shapes.RECTANGLE, { shadow, ... });

const makeShadow = () => ({ type: "outer", blur: 6, offset: 2, color: "000000", opacity: 0.15 });
slide.addShape(pres.shapes.RECTANGLE, { shadow: makeShadow(), ... });  // ✅ fresh object each time
slide.addShape(pres.shapes.RECTANGLE, { shadow: makeShadow(), ... });

Don't use ROUNDED_RECTANGLE with accent borders - rectangular overlay bars won't cover rounded corners. Use RECTANGLE instead.

// ❌ WRONG: Accent bar doesn't cover rounded corners
slide.addShape(pres.shapes.ROUNDED_RECTANGLE, { x: 1, y: 1, w: 3, h: 1.5, fill: { color: "FFFFFF" } });
slide.addShape(pres.shapes.RECTANGLE, { x: 1, y: 1, w: 0.08, h: 1.5, fill: { color: "0891B2" } });

// ✅ CORRECT: Use RECTANGLE for clean alignment
slide.addShape(pres.shapes.RECTANGLE, { x: 1, y: 1, w: 3, h: 1.5, fill: { color: "FFFFFF" } });
slide.addShape(pres.shapes.RECTANGLE, { x: 1, y: 1, w: 0.08, h: 1.5, fill: { color: "0891B2" } });

Quick Reference

Shapes: RECTANGLE, OVAL, LINE, ROUNDED_RECTANGLE
Charts: BAR, LINE, PIE, DOUGHNUT, SCATTER, BUBBLE, RADAR
Layouts: LAYOUT_16x9 (10"×5.625"), LAYOUT_16x10, LAYOUT_4x3, LAYOUT_WIDE
Alignment: "left", "center", "right"
Chart data labels: "outEnd", "inEnd", "center"

Install with Tessl CLI

npx tessl i gyan/pptx

references

scripts