🖊️ react-annotator-lite

A lightweight, extensible React component for image annotation. react-annotator-lite enables freehand drawing and threaded comments directly on images or canvases, with a responsive layout, rich metadata handling, and built-in UI components for action bars, comment sidebars, and overlays.

✨ Features

• Threaded Comments: Add comments and replies directly on images.
• Draggable Annotations: Move comments anywhere over the image.
• Drawing Tools: Freehand drawing with undo/redo, eraser, and color/stroke selection.
• Nearest Tag Visibility: Show the closest tag on hover for context.
• Layer Control: Toggle visibility of comments and drawing layers independently.
• Responsive Design: Works seamlessly on both desktop and mobile.
• Customizable UI: Replace built-in components or styles with your own.
• Performance Optimized: Uses React memoization and efficient event handling.

🚀 Quick Start

Installation

npm install react-annotator-lite
# or
yarn add react-annotator-lite

Usage Example

import React, { useState } from "react";
import Annotator from "react-annotator-lite";

//add the following line to include default styles
import 'react-annotator-lite/dist/index.css'

const App = () => {
  const [annotations, setAnnotations] = useState([]);
  const [paths, setPaths] = useState([]);

  const handleCommentAdd = (comment) => {
    setAnnotations((prev) => [...prev, comment]);
  };

  const handleReplyAdd = (reply, parentId) => {
    // Add reply logic
  };

  const handleSave = (metaData, canvasPaths) => {
    // Save logic
  };

  const handleDelete = (metadataId) => {
    // Delete logic
  };

  // Example: Custom tooltip for drawing paths
  const renderPathTooltip = (path, index) => (
    <div style={{ background: '#222', color: '#fff', padding: 4, borderRadius: 4 }}>
      <strong>Drawn by:</strong> {path.user?.userName || 'Unknown'}<br />
      <strong>Path #{index + 1}</strong>
    </div>
  );

  return (
    <div style={{ maxWidth: 800, margin: "0 auto" }}>
      <Annotator
        image_url="https://example.com/sample-image.jpg"
        initial_Annotations={annotations}
        initial_Paths={paths}
        onCommentAdd={handleCommentAdd}
        onReplyAdd={handleReplyAdd}
        onSave={handleSave}
        onDelete={handleDelete}
        enableDrawing={true}
        currentUserData={{ userId: "user-123", userName: "Alice" }}
        maxWidth={800}
        maxHeight={600}
        drawingOptions={{ strokeColor: '#00f', strokeWidth: 8 }}
        renderPathTooltip={renderPathTooltip}
      />
    </div>
  );
};

export default App;

📚 API Reference

<Annotator /> Props

Callback Details

• onCommentAdd(comment: MetaData): Called when a new comment is added. Receives the comment object.
• onReplyAdd(reply: MetaData, parentId: string): Called when a reply is added to a comment. Receives the reply and parent comment ID.
• onSave(metaData: MetaData[], paths: UserCanvasPath[]): Called when the user triggers a save action. Receives all metadata and drawing paths.
• onDelete(metadataId: string): Called when a comment or reply is deleted. Receives the metadata ID.

🧩 Custom Drawing Path Tooltip (renderPathTooltip)

You can provide a custom tooltip for each drawing path using the renderPathTooltip prop. This function receives the path object and its index, and should return a React node to display as a tooltip when hovering over a path.

Example:

const renderPathTooltip = (path, index) => (
  <div style={{ background: '#333', color: '#fff', padding: 6, borderRadius: 4 }}>
    <div>Drawn by: <b>{path.user?.userName || 'Unknown'}</b></div>
    <div>Path #{index + 1}</div>
    <div>Points: {path.paths.length}</div>
  </div>
);

<Annotator
  image_url="..."
  // ...other props
  renderPathTooltip={renderPathTooltip}
/>

🏗️ Architecture Overview

• Component Structure:
  • Annotator is the main component, managing state and context for annotation, drawing, and UI.
  • Modular subcomponents: SketchCanvas, MetaDataLayer, ActionBar, MetaDataSideBar, BottomMetaDataMenu, etc.
  • Uses React Context for state sharing and hooks for responsive layout and performance.
• Drawing Engine:
  • Freehand drawing with undo/redo, eraser, and color/stroke selection.
  • Drawing paths are normalized for responsive scaling.
• Comment System:
  • Threaded comments with drag-and-drop, reply, and delete support.
  • Sidebar and overlay UI for managing and viewing comments.
• Customization:
  • All UI elements can be styled or replaced via props.
  • Supports custom icons, toolbars, and comment rendering.

🤝 Contributing

Contributions are welcome! To contribute:

1. Fork the repository and create your branch from main.
2. Run npm install to install dependencies.
3. Make your changes and add tests if applicable.
4. Run npm run lint and npm run build to ensure code quality.
5. Submit a pull request with a clear description of your changes.

Guidelines

• Follow the existing code style and naming conventions.
• Write clear, concise commit messages.
• Add or update documentation as needed.
• Ensure all tests pass before submitting.

📄 License

MIT