pdfium_dart 0.2.0

Dart FFI bindings for PDFium library. Provides low-level access to PDFium's C API from Dart.

pdfium_dart

Dart FFI bindings for the PDFium library. This package provides low-level access to PDFium's C API from Dart.

This package is part of the pdfrx project.

Overview

This package contains auto-generated FFI bindings for PDFium using ffigen. It is designed to be a minimal, pure Dart package that other packages can depend on to access PDFium functionality.

Key Features:

• Pure Dart package with no Flutter dependencies
• Auto-generated FFI bindings using ffigen
• Provides direct access to PDFium's C API
• Downloads and bundles PDFium at build time using Dart native assets
• Includes getPdfium() for resolving PDFium across Dart and Flutter runtimes
• Supports Windows, Linux, Android, and macOS build hooks

Usage

Basic Usage

This package is primarily intended to be used as a dependency by higher-level packages like pdfium_flutter and pdfrx_engine. Direct usage is possible but not recommended unless you need low-level PDFium access.

import 'package:pdfium_dart/pdfium_dart.dart';
import 'dart:ffi';

// If you already have PDFium loaded
final pdfium = PDFium(DynamicLibrary.open('/path/to/libpdfium.so'));

PDFium Loading

The getPdfium function resolves the PDFium library for the current runtime. You can also pass an explicit module path for custom deployments or tests:

import 'package:pdfium_dart/pdfium_dart.dart';

void main() async {
  // Resolves PDFium for the current Dart or Flutter runtime.
  final pdfium = getPdfium();

  // Or load a specific shared library.
  final customPdfium = getPdfium(modulePath: '/path/to/libpdfium.so');

  // Use PDFium API
  // ...
}

The build hook downloads binaries from bblanchon/pdfium-binaries and exposes them through Dart native assets. At runtime, getPdfium() chooses the appropriate loading strategy:

• modulePath is used first when explicitly provided.
• Flutter apps on iOS/macOS use the PDFium XCFramework that is already linked into the app by pdfium_flutter.
• Native PDFium assets are not built for iOS; Flutter iOS apps should depend on pdfium_flutter so the XCFramework is linked by the Flutter plugin.
• Pure Dart commands on macOS, such as dart test, dart run, and dart compile, use the libpdfium.dylib native asset.
• Flutter apps on Linux look for libpdfium.so in the shared library directory relative to the resolved executable.
• Other supported platforms first try the platform library name, then fall back to the bundled native asset recorded in .dart_tool/native_assets.yaml.

Generating Bindings

Prerequisites

The ffigen process requires LLVM/Clang to be installed for parsing C headers:

• macOS: Install via Homebrew

  brew install llvm
  

• Linux: Install via package manager

  # Ubuntu/Debian
  sudo apt-get install libclang-dev
  
  # Fedora
  sudo dnf install clang-devel
  

• Windows: Download and install LLVM from llvm.org

Regenerating Bindings

To regenerate the FFI bindings:

1. Run tests once to download PDFium headers into test/.tmp:

   dart test
   

2. Generate bindings:

   dart run ffigen
   

The bindings are generated from PDFium headers using the configuration in ffigen.yaml.

Platform Support

Platform	Architecture	Support
Windows	x64, ARM64, x86	✅
Linux	x64, ARM64, ARM, x86	✅
Android	ARM64, ARMv7, x86, x86_64	✅
macOS	x64, ARM64	✅

Note: For Flutter applications, use pdfium_flutter unless you specifically need the lower-level Dart bindings directly. pdfium_flutter includes the Flutter deployment layer for all native platforms except Web.