native_pdf_engine #

A minimal, high-performance Flutter package for generating PDFs from HTML or URLs using native OS webview capabilities.

This package uses dart:ffi and package:jni to invoke native APIs directly, ensuring:

• Zero bloat: No bundled browser engines (uses pre-installed OS webviews).
• High performance: Direct native calls, low overhead.
• Native fidelity: PDFs look exactly as they would when printing from Safari (iOS/macOS) or Chrome (Android).

Platforms Supported #

Features #

• Convert HTML String to PDF: Render raw HTML content directly to a PDF file.
• Convert URL to PDF: Capture a full webpage and save it as a PDF.
• Background Execution: Most operations run efficiently without blocking the main UI thread (Android uses runOnUiThread for safety).

Installation #

Add native_pdf_engine to your pubspec.yaml:

dependencies:
  native_pdf_engine: ^0.0.1

Setup #

Android #

1. Internet Permission: If you are converting URLs, ensure your android/app/src/main/AndroidManifest.xml includes:

   <uses-permission android:name="android.permission.INTERNET" />
   

2. Cleartext Traffic: If you need to support HTTP URLs (not recommended), allow cleartext traffic in your manifest or network security config.

iOS / macOS #

No special setup is usually required. App Sandbox/Hardened Runtime on macOS may require allowing outgoing network connections (com.apple.security.network.client) if fetching URLs.

Usage #

import 'package:native_pdf_engine/native_pdf_engine.dart';

void main() async {
  // 1. Convert HTML String
  try {
     await NativePdf.convert(
       '<h1>Hello World</h1><p>This is a native PDF!</p>',
       'output/path/document.pdf',
     );
     print('PDF Generated!');
  } catch (e) {
     print('Error: $e');
  }

  // 2. Convert URL
  try {
     await NativePdf.convertUrl(
       'https://flutter.dev',
       'output/path/flutter_website.pdf',
     );
     print('URL Captured!');
  } catch (e) {
     print('Error: $e');
  }
}

How It Works #

This package avoids the complexity of flutter_inappwebview or printing when you just need a simple, headless PDF generation:

• Android: It spins up a headless WebView, loads the content, waits for completion (via polling), and draws the view hierarchy onto a android.graphics.pdf.PdfDocument Canvas.
• iOS/macOS: It creates a headless WKWebView, loads the content, and uses the native createPDF configuration API available in WebKit.

License #

MIT