HTML to PPTX

Turn a finished HTML deck into a native, fully‑editable PowerPoint (.pptx). Real text boxes and shapes you can keep editing — not flat screenshots.

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Why

You have a polished HTML presentation and you want it as a PowerPoint that recipients can reuse like a template — clicking a title to retype it, recoloring a shape, nudging a box. A screenshot‑to‑PPT export gives you flat images you can't edit.

HTML to PPTX renders your deck in real headless Chromium, measures every element, and rebuilds each slide as native PowerPoint text boxes, shapes and vector SVG — with fonts embedded and on‑screen line breaks preserved.

Editable conversion is, by design, not pixel‑perfect (PowerPoint re‑flows text). It's tuned for the template use case, where small shifts are fine. If you need a pixel‑exact, non‑editable copy, export a PDF instead (out of scope here).

Features

• 🧩 Native, editable output — text boxes, shapes and vector charts, not images.
• 🔤 Automatic font embedding — web fonts (Pretendard, Google Fonts…) are fetched Node‑side and embedded, including the real bold face, so layout doesn't drift.
• ↩️ Line‑break locking — the exact on‑screen wrap points are baked in so PowerPoint shows the same breaks (no mid‑word splits when a fallback font is wider).
• 📐 Any aspect ratio — the source slide ratio is auto‑detected (16:9, 4:3, portrait, ultrawide); no forced cropping.
• 🎞️ Slideshow decks handled — web‑component / reveal.js style decks (<deck-stage>) that show one slide at a time are auto‑switched to their print layout so every slide exports (no blank white slides).
• 🌏 CJK‑ready — Korean/Japanese/Chinese decks keep their fonts (incl. bold) and exact line breaks; Unicode filenames are preserved on save.
• 🔒 100% local & offline — your files never leave your machine. Fonts are self‑hosted.
• 🖥️ Three ways to run — a CLI, a local web app, and a desktop app (Windows installer).

Screens

Choose a file	Ready to convert	Done

Quick start

Requires Node.js ≥ 18. The first install downloads a bundled Chromium via Puppeteer.

git clone https://github.com/mmoollee101-lab/HTMLtoPPTX.git
cd HTMLtoPPTX
npm install
npm run sample        # converts samples/sample.html → samples/sample.pptx

Desktop app (Windows installer)

Grab HTML-to-PPTX-<version>-setup.exe from the Releases page and run it. It installs per‑user (no admin), adds Start‑menu / Desktop shortcuts and an uninstaller. No Node, no browser, no setup — Chromium is bundled; it unpacks once at install, then every launch is near‑instant. The app opens a single frameless window with standard minimize / close controls, and converted files land in your Downloads folder.

The installer is unsigned, so Windows SmartScreen / antivirus may warn on first run ("Windows protected your PC" → More info → Run anyway). Code signing is on the roadmap.

Build it yourself (from a clone):

npm run app           # dev: run the Electron app from source
npm run dist          # build dist/HTML-to-PPTX-<version>-setup.exe (Windows NSIS installer)

npm run dist stages the bundled Chromium (predist) and packages the installer via electron‑builder. (The older Puppeteer --app launcher is still available as npm run app:server.)

Web app (any browser)

npm run web           # then open http://localhost:3000

Drag in a .html file (or pick one), optionally set a slide selector, and convert. The .pptx is written to your Downloads folder; Open / Show in folder launch it through the OS.

The web/app modes can't resolve relative asset paths in uploaded HTML — use self‑contained HTML (absolute URLs or data: URIs) for images and fonts. Decks with many local relative assets are best converted with the CLI.

CLI

# single file (output name is inferred: deck.html → deck.pptx)
node src/cli.js deck.html

# explicit output, custom slide selector
node src/cli.js deck.html slides.pptx -s "section.slide"

# batch: convert every .html in a folder
node src/cli.js ./decks ./out -s ".page"

node src/cli.js --help

Option	Description	Default
<input>	input .html file or a folder (batch)	required
[output] / -o, --out	output .pptx (single) or output folder (batch)	inferred
-s, --selector	CSS selector for one slide	auto / .slide
--aspect <w:h>	force slide aspect ratio	auto‑detect
--no-lock-breaks	let PowerPoint re‑flow text instead of freezing breaks	off
--no-embed-fonts	don't embed web fonts (smaller file, may shift)	off
--print / --no-print	force / disable the slideshow print layout	auto

If the selector matches nothing, the tool prints the candidate ids/classes it found.

How it works

1. Render — Puppeteer (headless Chromium) loads the HTML and waits for web fonts, so dom-to-pptx measures real glyph metrics.
2. Resolve & fix — embeddable font URLs are fetched Node‑side; inline‑margin gaps and decorative pseudo‑element markers are normalized; soft line breaks are baked to <br>.
3. Convert — dom-to-pptx exports the slide elements to absolutely‑positioned PPTX boxes, keeping SVG as vectors. Post‑processing fixes line spacing and adds the bold face.

src/convert.js     conversion engine (Puppeteer + dom-to-pptx) — shared by CLI/web/app
src/cli.js         CLI (arg parsing, batch, errors)
src/server.js      local web server (Node http only) — detect/convert/open/reveal endpoints
src/util.js        shared helpers (output dir, filename dedup, path guard)
electron/          Electron shell — main.js (window + IPC) + preload.js (window.api bridge)
scripts/           build helpers (resolve-chromium.js stages the bundled browser)
public/            desktop UI (self-hosted fonts + icons) — IPC in Electron, fetch on the web
samples/           sample deck
docs/              design + PDCA notes

Fidelity tips

• Author at a fixed pixel size (e.g. 1920×1080 or 1024×768). vw/vh/% units are measured against the 1920×1080 viewport and can throw off the detected ratio.
• Korean / CJK: use word-break: keep-all and leave a little slack in text boxes so replacement copy doesn't overflow.
• Fonts: woff, woff2, ttf and otf web fonts are all embedded automatically — including fonts inlined as data: URIs (self-contained decks) and cross-origin CDN fonts. woff2 is decoded to TrueType so PowerPoint (which can't read woff2) embeds the real face, and a matching bold weight is added so bold text isn't rendered as a mismatched faux-bold.

Roadmap

• Package as a desktop app (Electron) with a frameless window, native file dialogs and a bundled Chromium — no Node install required. Ships as a Windows installer. (npm run dist)
• Code signing (remove the SmartScreen/AV warning).
• Per‑slide real conversion progress.
• Prebuilt releases for macOS / Linux (Windows installer ships today).

FAQ

Is the output pixel‑perfect? No — by design. PowerPoint re‑flows text, so expect minor shifts. The goal is an editable deck you can reuse as a template. For a pixel‑exact, non‑editable copy, export a PDF instead.

Does it really work offline? Yes. Everything runs on your machine, the UI fonts are self‑hosted, and the desktop app bundles its own Chromium. Nothing is uploaded.

Why is my .pptx large? Embedded fonts and vector graphics add weight. Pass --no-embed-fonts to shrink it (the layout may shift to a fallback font).

My slides came out blank / white. Your deck probably shows one slide at a time (a slideshow web component like <deck-stage> or reveal.js). These are auto‑detected and exported via their print layout — if yours isn't, force it with --print or pass the right --selector.

Does it support Korean / Japanese / Chinese? Yes — CJK fonts (including bold) are embedded and line breaks are locked. Use word-break: keep-all and leave a little slack in text boxes. Unicode filenames are kept.

Windows warns the installer .exe is unsafe. The binary is unsigned, so SmartScreen shows a warning. Verify you got it from the official Releases page, then More info → Run anyway. Code signing is on the roadmap.

Contributing

Issues and PRs welcome — see CONTRIBUTING.md. Please also read the Code of Conduct. The UI is built from the spec in design_handoff_html_to_pptx/; security reports go through SECURITY.md.

Acknowledgements

Built on dom-to-pptx and Puppeteer. UI typefaces are Hanken Grotesk and JetBrains Mono, both under the SIL Open Font License.

License

MIT © contributors. Bundled fonts (Hanken Grotesk, JetBrains Mono) are licensed under the SIL Open Font License 1.1.