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libvips_ffi_core

Pure Dart FFI bindings for libvips. No Flutter dependency.

Installation​

dependencies:
  libvips_ffi_core: ^0.1.0+8.16.0
note

This package provides FFI bindings only. You need to load the library separately.

Features​

  • Pure Dart (no Flutter dependency)
  • Generated bindings from libvips headers
  • VarArgs support for variadic functions
  • Memory management utilities

Core Classes​

VipsCore​

Static class for library initialization and version info.

// Initialize libvips
VipsCore.init();

// Get version
print(VipsCore.version);     // e.g., "8.16.0"
print(VipsCore.majorVersion); // e.g., 8

// Shutdown
VipsCore.shutdown();

VipsPointerManager​

Memory management for native pointers.

final manager = VipsPointerManager();
try {
  final ptr = manager.allocate<Int>(10);
  // Use ptr...
} finally {
  manager.freeAll();
}

LibraryLoader​

Platform-specific library loading.

// Automatic detection
final lib = LibraryLoader.load();

// Custom path
final lib = LibraryLoader.loadFromPath('/path/to/libvips.so');

Enums​

The package exports libvips enums:

VipsDirection.horizontal
VipsDirection.vertical

VipsInterpretation.sRGB
VipsInterpretation.lab
VipsInterpretation.grey16

VipsBlendMode.over
VipsBlendMode.multiply
VipsBlendMode.screen

// ... and many more

Low-Level Usage​

For advanced users who need direct FFI access:

import 'package:libvips_ffi_core/libvips_ffi_core.dart';
import 'dart:ffi' as ffi;

void main() {
  VipsCore.init();
  
  final bindings = VipsCore.bindings;
  
  // Direct FFI call
  final namePtr = 'input.jpg'.toNativeUtf8();
  final imagePtr = bindings.vips_image_new_from_file(
    namePtr.cast(),
    ffi.nullptr,  // NULL terminator for variadic args
  );
  
  if (imagePtr != ffi.nullptr) {
    print('Width: ${bindings.vips_image_get_width(imagePtr)}');
    bindings.g_object_unref(imagePtr.cast());
  }
  
  calloc.free(namePtr);
  VipsCore.shutdown();
}

When to Use​

Use libvips_ffi_core when:

  • Building a custom high-level API
  • Need direct FFI access for performance
  • Working in a non-Flutter Dart environment
  • Creating specialized image processing tools

For most use cases, prefer libvips_ffi_api which provides a friendlier API.