mcpbeat

Snapdom

aiskillstore/snapdom

snapDOM is a fast, accurate DOM-to-image capture tool that converts HTML elements into scalable SVG images. Use for capturing HTML elements, converting DOM to images (SVG, PNG, JPG, WebP), preserving styles, fonts, and pseudo-elements.

This is a copy. The original lives at comeonoliver/snapdom.

17k tokens
context cost
the whole folder, loaded on every use
4
files
instructions only
0
copies elsewhere
how many repositories repackaged it
404
stars on the repo
on the repository, not the skill itself

Install

one command, takes just this skill from the repository
npx skills add https://github.com/aiskillstore/marketplace --skill snapdom

What comes with it

59 653 bytes besides the instruction
references/index.md
references/other.md
skill-report.json

The instruction itself

40 sections, as written by the author

SnapDOM Skill

Fast, dependency-free DOM-to-image capture library for converting HTML elements into scalable SVG or raster image formats.

When to Use This Skill

Use SnapDOM when you need to:

  • Convert HTML elements to images (SVG, PNG, JPG, WebP)
  • Capture styled DOM with pseudo-elements and shadows
  • Export elements with embedded fonts and icons
  • Create screenshots with custom dimensions or scaling
  • Handle CORS-blocked resources using proxy fallback
  • Implement custom rendering pipelines with plugins
  • Optimize performance on large or complex elements

Key Features

Universal Export Options

  • SVG - Scalable vector format, embeds all styles
  • PNG, JPG, WebP - Raster formats with configurable quality
  • Canvas - Get raw Canvas element for further processing
  • Blob - Raw binary data for custom handling

Performance

  • Ultra-fast capture (1.6ms for small elements, ~171ms for 4000×2000)
  • No dependencies - Uses standard Web APIs only
  • Outperforms html2canvas by 10-40x on complex elements

Style Support

  • Embedded fonts (including icon fonts)
  • CSS pseudo-elements (::before, ::after)
  • CSS counters
  • CSS line-clamp
  • Transform and shadow effects
  • Shadow DOM content

Advanced Capabilities

  • Same-origin iframe support
  • CORS proxy fallback for blocked assets
  • Plugin system for custom transformations
  • Straighten transforms (remove rotate/translate)
  • Selective element exclusion
  • Tight bounding box calculation

Installation

NPM/Yarn

npm install @zumer/snapdom
# or
yarn add @zumer/snapdom

CDN (ES Module)

<script type="module">
  import { snapdom } from "https://unpkg.com/@zumer/snapdom/dist/snapdom.mjs";
</script>

CDN (UMD)

<script src="https://unpkg.com/@zumer/snapdom/dist/snapdom.umd.js"></script>

Quick Start Examples

Basic Reusable Capture

// Create reusable capture object
const result = await snapdom(document.querySelector('#target'));

// Export to different formats
const png = await result.toPng();
const jpg = await result.toJpg();
const svg = await result.toSvg();
const canvas = await result.toCanvas();
const blob = await result.toBlob();

// Use the result
document.body.appendChild(png);

One-Step Export

// Direct export without intermediate object
const png = await snapdom.toPng(document.querySelector('#target'));
const svg = await snapdom.toSvg(element);

Download Element

// Automatically download as file
await snapdom.download(element, 'screenshot.png');
await snapdom.download(element, 'image.svg');

With Options

const result = await snapdom(element, {
  scale: 2,                    // 2x resolution
  width: 800,                  // Custom width
  height: 600,                 // Custom height
  embedFonts: true,            // Include @font-face
  exclude: '.no-capture',      // Hide elements
  useProxy: true,              // Enable CORS proxy
  straighten: true,            // Remove transforms
  noShadows: false             // Keep shadows
});

const png = await result.toPng({ quality: 0.95 });

Essential Options Reference

| Option | Type | Purpose |

|--------|------|---------|

| scale | Number | Scale output (e.g., 2 for 2x resolution) |

| width | Number | Custom output width in pixels |

| height | Number | Custom output height in pixels |

| embedFonts | Boolean | Include non-icon @font-face rules |

| useProxy | String\|Boolean | Enable CORS proxy (URL or true for default) |

| exclude | String | CSS selector for elements to hide |

| straighten | Boolean | Remove translate/rotate transforms |

| noShadows | Boolean | Strip shadow effects |

Common Patterns

Responsive Screenshots

// Capture at different scales
const mobile = await snapdom.toPng(element, { scale: 1 });
const tablet = await snapdom.toPng(element, { scale: 1.5 });
const desktop = await snapdom.toPng(element, { scale: 2 });

Exclude Elements

// Hide specific elements from capture
const png = await snapdom.toPng(element, {
  exclude: '.controls, .watermark, [data-no-capture]'
});

Fixed Dimensions

// Capture with specific size
const result = await snapdom(element, {
  width: 1200,
  height: 630  // Standard social media size
});

CORS Handling

// Fallback for CORS-blocked resources
const png = await snapdom.toPng(element, {
  useProxy: 'https://cors.example.com/?' // Custom proxy
});

Plugin System (Beta)

// Extend with custom exporters
snapdom.plugins([pluginFactory, { colorOverlay: true }]);

// Hook into lifecycle
defineExports(context) {
  return {
    pdf: async (ctx, opts) => { /* generate PDF */ }
  };
}

// Lifecycle hooks available:
// beforeSnap → beforeClone → afterClone →
// beforeRender → beforeExport → afterExport

Performance Comparison

SnapDOM significantly outperforms html2canvas:

| Scenario | SnapDOM | html2canvas | Improvement |

|----------|---------|-------------|-------------|

| Small (200×100) | 1.6ms | 68ms | 42x faster |

| Medium (800×600) | 12ms | 280ms | 23x faster |

| Large (4000×2000) | 171ms | 1,800ms | 10x faster |

Development

Setup

git clone https://github.com/zumerlab/snapdom.git
cd snapdom
npm install

Build

npm run compile

Testing

npm test

Browser Support

  • Chrome/Edge 90+
  • Firefox 88+
  • Safari 14+
  • Mobile browsers (iOS Safari 14+, Chrome Mobile)

Resources

Documentation

  • Official Website: https://snapdom.dev/
  • GitHub Repository: https://github.com/zumerlab/snapdom
  • NPM Package: https://www.npmjs.com/package/@zumer/snapdom
  • License: MIT

scripts/

Add helper scripts here for automation, e.g.:

  • batch-screenshot.js - Capture multiple elements
  • pdf-export.js - Convert snapshots to PDF
  • compare-outputs.js - Compare SVG vs PNG quality

assets/

Add templates and examples:

  • HTML templates for common capture scenarios
  • CSS frameworks pre-configured with snapdom
  • Boilerplate projects integrating snapdom
  • html2canvas - Alternative DOM capture (slower but more compatible)
  • Orbit CSS Toolkit - Companion toolkit by Zumerlab (https://github.com/zumerlab/orbit)

Tips & Best Practices

  • Performance: Use scale instead of width/height for better performance
  • Fonts: Set embedFonts: true to ensure custom fonts appear correctly
  • CORS Issues: Use useProxy: true if images fail to load
  • Large Elements: Break into smaller chunks for complex pages
  • Quality: For PNG/JPG, use quality: 0.95 for best quality
  • SVG Vectors: Prefer SVG export for charts and graphics

Troubleshooting

Elements Not Rendering

  • Check if element has sufficient height/width
  • Verify CSS is fully loaded before capture
  • Try straighten: false if transforms are causing issues

Missing Fonts

  • Set embedFonts: true
  • Ensure fonts are loaded before calling snapdom
  • Check browser console for font loading errors

CORS Issues

  • Enable useProxy: true
  • Use custom proxy URL if default fails
  • Check if resources are from same origin

Performance Issues

  • Reduce scale value
  • Use noShadows: true to skip shadow rendering
  • Consider splitting large captures into smaller sections

How to use it

Copy the folder

Take aiskillstore/snapdom from the repository into ~/.claude/skills for personal use, or into .claude/skills inside a project.

Check the name does not clash

The agent identifies a skill by the name field in its header. Two skills with the same name cannot sit side by side — one of them will be ignored.

Install what it needs

The instructions reference npm, yarn. Without those the skill loads but fails at the first command.