pdfrx_engine

pdfrx_engine is a platform-agnostic PDF rendering engine built on top of PDFium. It provides low-level PDF document APIs without any Flutter dependencies, making it suitable for use in pure Dart applications, CLI tools, or server-side processing.

This package is a part of pdfrx Flutter plugin, which adds UI widgets and Flutter-specific features on top of this engine.

Multi-platform support

• Android
• iOS
• Windows
• macOS
• Linux (even on Raspberry Pi)
• Web (WASM) supported only on Flutter by pdfrx

Example Code

The following fragment illustrates how to use the PDF engine to load and render a PDF file:

import 'dart:io';
import 'package:image/image.dart' as img;
import 'package:pdfrx_engine/pdfrx_engine.dart';

void main() async {
  await pdfrxInitialize();

  final document = await PdfDocument.openFile('test.pdf');
  final page = document.pages[0]; // first page
  final pageImage = await page.render(
    width: page.width * 200 / 72,
    height: page.height * 200 / 72,
  );
  final image = pageImage!.createImageNF();
  await File('output.png').writeAsBytes(img.encodePng(image));
  pageImage.dispose();
  document.close();
}

You should call pdfrxInitialize() before using any PDF engine APIs to ensure the native PDFium library is properly loaded. For more information, see pdfrx Initialization

PDF API

• Easy to use PDF APIs
  • PdfDocument - Main document interface
    • PdfDocument.openFile - Open PDF from file path
    • PdfDocument.openData - Open PDF from memory (Uint8List)
    • PdfDocument.openUri - Open PDF from stream (advanced use case)
    • PdfDocument.openAsset - Open PDF from Flutter asset
  • PdfPage - Page representation and rendering
    • PdfPage.render - Render page to bitmap
    • PdfPage.loadText - Extract text content from page
    • PdfPage.loadLinks - Extract links from page
• PDFium bindings
  • For advanced use cases, you can access the raw PDFium bindings via package:pdfrx_engine/src/native/pdfium_bindings.dart
  • Note: Direct use of PDFium bindings is not recommended for most use cases

When to Use pdfrx_engine vs. pdfrx

Use pdfrx_engine when:

• Building CLI tools or server applications
• You need PDF rendering without Flutter UI
• Creating custom PDF processing pipelines
• Working in pure Dart environments

Use pdfrx when:

• Building Flutter applications
• You need ready-to-use PDF viewer widgets
• You want features like text selection, search, and zoom controls
• You prefer high-level APIs with Flutter integration