@wity/scene-to-pptx

Server-side presentation renderer. Snapshots a wity-scene document at one or more timestamps and produces a PowerPoint (.pptx) file using node-canvas and pptxgenjs. Node.js / Lambda only, not browser-compatible.

The output is directly importable into PowerPoint, Keynote, and Google Slides.

Entry point: Call witySceneRender with outputFormat: "pptx" — do not invoke this Lambda directly. See the Deployment guide.

Install

npm install @wity/scene-to-pptx
# peer deps:
npm install @wity/scene-core @xmldom/xmldom

---

render(sceneXml, fontManifest, options)

Render scene snapshots to a PowerPoint file on disk.

render(
  sceneXml:     string,
  fontManifest: Record<string, string>,
  options: {
    ts?:         number,
    timestamps?: number[],
  }
): Promise<{ pptxPath: string, cleanup: () => Promise<void> }>

Argument	Type	Description
sceneXml	string	Raw <wity-scene> XML
fontManifest	Record<string, string>	Font family name → URL. Pass {} if no custom fonts.
options.ts	number (default 0)	Scene time in seconds to snapshot. Ignored when timestamps is provided.
options.timestamps	number[]	Array of scene times — each produces one slide.

Returns:

Field	Description
pptxPath	Absolute path of the rendered .pptx in /tmp
cleanup	Call after upload to remove temp files

import { render } from '@wity/scene-to-pptx';

// Single slide at t=0
const { pptxPath, cleanup } = await render(sceneXml, {}, { ts: 0 });
// upload pptxPath to storage...
await cleanup();

// Multi-slide deck: one slide per timestamp
const { pptxPath, cleanup } = await render(sceneXml, fontManifest, {
  timestamps: [0, 5.0, 10.0, 15.0],
});

---

Slide layout

The presentation layout is set to the scene's pixel dimensions interpreted at 96 DPI (standard screen PPI), preserving the exact aspect ratio:

• 1920 × 1080 scene → 20" × 11.25" slides (widescreen 16:9)
• 1080 × 1920 scene → 11.25" × 20" slides (portrait / reels)

Each slide contains the rendered scene frame as a full-bleed pixel-perfect PNG image.

---

What is rendered

Element type	Rendered?
ws-rect	Yes — filled rectangles, stroke, border-radius
ws-text	Yes — font, color, animation state at ts
ws-image	Yes — image with fit modes
ws-video	No — skipped silently (graphics snapshot only)
ws-audio	No — skipped silently

Animation and keyframe state is fully resolved at each ts — evaluate(scene, ts) produces the exact visual frame per slide.

---

Lambda deployment

The witySceneToPptx Lambda wraps this package.

Input:

{
  "sceneXml":    "<wity-scene>...</wity-scene>",
  "fontManifest": {},
  "timestamps":  [0, 5.0, 10.0]
}

Response:

{ "url": "https://...", "fileSize": 456789, "slides": 3 }

Config	Value
Function name	witySceneToPptx
Memory	1024 MB
Timeout	120 s
Ephemeral storage	1024 MB
Runtime	Node.js 20
FFmpeg layer	Not required