- name
- snapdom
- description
- DOM capture engine that can export any DOM subtree as SVG, PNG, JPG, WebP, Canvas, or Blob, supporting inline styles, fonts, background images, pseudo-elements, and Shadow DOM.
snapdom — DOM Capture Engine
Use Cases
Use this skill when users request to take a screenshot of a web page element, DOM node, or HTML fragment, export it as an image, generate a web page snapshot, or convert any DOM element to an image/Canvas.
Installation
NPM:
npm i @zumer/snapdomCDN (script tag):
<script src="https://unpkg.com/@zumer/snapdom/dist/snapdom.js"></script>Quick Start
Shortcuts (One-off export)
import { snapdom } from '@zumer/snapdom';
// Export a DOM element as PNG
const png = await snapdom.toPng(document.querySelector('#card'));
document.body.appendChild(png);
// Other formats
const blob = await snapdom.toBlob(document.querySelector('#card'));
const svgImg = await snapdom.toSvg(document.querySelector('#card'));Reusable Capture (Clone once, export multiple times)
const result = await snapdom(document.querySelector('#card'));
const png = await result.toPng();
const jpg = await result.toJpg({ quality: 0.92 });
await result.download({ format: 'jpg', filename: 'card.jpg' });Common Options
| Option | Type | Default | Description |
|---|---|---|---|
scale | number | 1 | Output scale multiplier |
width / height | number | - | Force output dimensions |
quality | number | 1 | JPG/WebP quality 0~1 |
backgroundColor | string | "#fff" | Background color for JPG/WebP |
embedFonts | boolean | false | Embed non-icon fonts |
useProxy | string | '' | CORS proxy URL |
exclude | string[] | - | CSS selectors to exclude |
filter | function | - | Filter function (el) => boolean |
debug | boolean | false | Output silent errors to console.warn |
Examples
// High-definition screenshot (2x)
await snapdom.toPng(el, { scale: 2 });
// CORS cross-origin images
await snapdom.toPng(el, { useProxy: 'https://proxy.corsfix.com/?' });
// Exclude elements
await snapdom.toPng(el, { exclude: ['.cookie-banner', '.tooltip'] });
// Filter out display:none elements
await snapdom.toPng(document.body, {
filter: el => window.getComputedStyle(el).display !== 'none'
});xbrowser Integration
When capturing in a xbrowser environment, SnapDOM must be run through the browser's execution context. Recommended pattern:
// After an xbrowser snapshot, execute in the page via evaluate
await browser.evaluate(async (selector) => {
const { snapdom } = window._snapdom || await import('https://unpkg.com/@zumer/snapdom/dist/snapdom.mjs');
const el = document.querySelector(selector);
if (!el) throw new Error(`Element not found: ${selector}`);
const result = await snapdom(el, { scale: 2, embedFonts: true });
const dataUrl = await result.toPng();
return dataUrl;
}, selector);See references/api_reference.md for detailed API documentation and full options list.
Plugins
Install official plugins:
npm install @zumer/snapdom-pluginsRegister and use:
import { snapdom } from '@zumer/snapdom';
import { filter, timestampOverlay } from '@zumer/snapdom-plugins';
snapdom.plugins(
[filter, { preset: 'grayscale' }],
[timestampOverlay, { position: 'bottom-right' }]
);
const out = await snapdom(element);
const png = await out.toPng();Plugin lifecycle hooks: beforeSnap → beforeClone → afterClone → beforeRender → afterRender → beforeExport → afterExport.
Example Reference assets/demo.html。