Prism-Notes-Main/tools/screen-capture/README.md

Screen Capture Tool

A standalone utility for capturing screenshots from user's screen using the native Browser Screen Capture API.

Features

• 📸 Capture screenshots from user-selected screen/window
• 🎯 No external dependencies
• ⚡ Returns canvas for flexible post-processing
• 🛡️ Graceful error handling
• ♿ Respects user permissions

Installation

Copy the screen-capture folder to your project:

your-project/
├── tools/
│   └── screen-capture/
│       ├── index.js
│       └── README.md

Usage

Basic Screenshot Capture

import { captureScreenshot } from './tools/screen-capture/index.js';

const canvas = await captureScreenshot();
if (canvas) {
  // Canvas is ready for use
  // Convert to File, display, or manipulate further
}

Convert to File

import { captureScreenshot, canvasToFile } from './tools/screen-capture/index.js';

const canvas = await captureScreenshot();
if (canvas) {
  const file = await canvasToFile(canvas, 'my-screenshot.png');
  // Use file with FormData, attachments, etc.
}

One-liner with Blob

const canvas = await captureScreenshot();
canvas?.toBlob((blob) => {
  const file = new File([blob], `screenshot-${Date.now()}.png`, { type: 'image/png' });
  // Use file...
});

API Reference

captureScreenshot()

Returns: Promise<Canvas | null>

Opens native browser dialog for user to select screen/window to capture. Returns a canvas element containing the screenshot, or null if user cancels or error occurs.

Example:

const canvas = await captureScreenshot();

canvasToFile(canvas, filename?)

Parameters:

• canvas (Canvas): Canvas element to convert
• filename (string, optional): Custom filename. Defaults to screenshot-{timestamp}.png

Returns: Promise<File>

Converts canvas to PNG File object for easy handling in file uploads or attachments.

Example:

const file = await canvasToFile(canvas, 'custom-name.png');

Browser Support

Requires browsers supporting the Screen Capture API:

• Chrome 72+
• Edge 79+
• Firefox 66+
• Safari 13+

Note: User must grant permission for each capture request.

Error Handling

The tool gracefully handles:

• User cancellation of the capture dialog
• Browser permission denial
• Browser incompatibility
• Missing canvas/video support

All errors are logged to console and return null.

Examples

React Component

import { captureScreenshot, canvasToFile } from './tools/screen-capture/index.js';

export function ScreenshotButton() {
  const handleCapture = async () => {
    const canvas = await captureScreenshot();
    if (canvas) {
      const file = await canvasToFile(canvas);
      console.log('Screenshot captured:', file.name);
    }
  };

  return <button onClick={handleCapture}>Take Screenshot</button>;
}

With Form Submission

import { captureScreenshot, canvasToFile } from './tools/screen-capture/index.js';

const canvas = await captureScreenshot();
if (canvas) {
  const file = await canvasToFile(canvas);
  
  const formData = new FormData();
  formData.append('screenshot', file);
  
  await fetch('/api/upload', { method: 'POST', body: formData });
}

License

MIT - Use freely in your projects