vite-plugin-kapar

vite-plugin-kapar is a Vite dev-plugin for taking screenshots and recording .webm videos of your web application directly from the DOM.

It injects a sleek floating widget into your application during development, leveraging the experimental HTML-in-Canvas API to achieve zero-permission screen captures. It completely bypasses clunky getDisplayMedia screen-sharing prompts.

As a bonus, it includes a Grease Pencil (Pen) feature, allowing you to annotate your screen in real-time while recording demos or finding bugs.

Key Features

• Vite Dev Plugin: Injects seamlessly during development mode (apply: 'serve'), zero impact on production builds.
• Framework Agnostic: Bundles its UI runtime internally—works out of the box with Vue, Svelte, React, Solid, or Vanilla JS projects.
• Zero Permission Prompts: No "Share your screen" popups.
• Pixel-Perfect Scaling: Define exact capture dimensions regardless of your actual viewport.
• Fully Interactive: The captured DOM elements remain interactive (clicks, hovers, inputs).
• Built-in Pen Tool: Draw over your application in real-time.

Prerequisites (Crucial)

Because the HTML-in-Canvas API is currently experimental, this package requires specific browser settings to work:

1. Use Chrome Canary (or Chromium 147+).
2. Navigate to chrome://flags/#canvas-draw-element.
3. Enable the HTML elements in canvas flag and restart your browser.

Installation

Install the package via NPM as a development dependency:

npm install vite-plugin-kapar -D

Usage

Add the plugin to your vite.config.ts.

import { defineConfig } from 'vite';
import { kaparPlugin } from 'vite-plugin-kapar';

export default defineConfig({
  plugins: [
    kaparPlugin({
      targetSelector: '#app-wrapper' // Optional: target your app's main wrapper (defaults to #app, #root, or body)
    })
  ]
});

Once configured, start your Vite dev server (npm run dev). A floating widget will automatically appear in the bottom right corner of your app, giving you instant access to screenshot, recording, and pen tools.

Local Testing & Development

If you want to contribute to kapar or test it locally within another project:

1. Clone and Build:

git clone https://github.com/zerdalu/kapar.git
cd kapar
npm install
npm run build
npm link

2. Link to a local test project:

# Inside your test project folder (e.g., a blank Vite app):
npm link vite-plugin-kapar

Known Issues

• Viewport-Fixed Elements (position: fixed): Elements styled with position: fixed relative to the browser viewport may not appear inside the capture canvas. Workaround: Wrap fixed elements or assign them position: absolute relative to your targeted application container.
• Cross-Origin Content (CORS): Elements containing cross-origin resources (such as external images, web fonts, or nested <iframe> contents) may fail to render or taint the canvas due to browser security boundaries.
• Experimental API Reliance: Since this uses the experimental drawElementImage API, performance and rendering stability are tied to the browser's experimental canvas implementation.

Roadmap

• Video Quality and Bitrate Controls: Expose advanced configuration options for video capturing (e.g., custom bitrates, VP9/AV1 encoding formats) to maximize output recording quality.
• Enhanced Grease Pencil Tools: Expand the annotation tool with vector shapes (arrows, rectangles, circles), an eraser brush, and adjustable brush opacity.
• Audio Capture Integration: Add options to capture microphone audio track inputs alongside the video stream during session recording.
• Additional Image Export Formats: Support exporting screenshots as .webp or .jpeg alongside standard .png.
• Preflight Style Refinements: Optimize the inline CSS preflight reset to ensure broader layout rendering compatibility inside the Shadow DOM widget.

License

MIT © zerdalu