blurhash_ffi 1.0.0

Blurhash encoder and decoder for flutter using native C code with ffi bindings.

blurhash_ffi

A Blurhash compact Image placeholder encoder and decoder FFI implementation for flutter in C, Supports Android, iOS, Linux, macOS and Windows.

Matches the official Blurhash implementation in performance and quality.

Usage

To use this plugin, add blurhash_ffi as a dependency in your pubspec.yaml file

Encoding

import 'package:blurhash_ffi/blurhash_ffi.dart';

/// Encoding a blurhash from an image provider
///
/// You can use any ImageProvider you want, including NetworkImage, FileImage, MemoryImage, AssetImage, etc.
final imageProvider = NetworkImage('https://picsum.photos/512');
final imageProvider2 = AssetImage('assets/image.jpg');

/// Signature
/// static Future<String> encode(
///   ImageProvider imageProvider, {
///   int componentX = 4,
///   int componentY = 3,
/// })
/// may throw `BlurhashFFIException` if encoding fails.
final String blurHash = await BlurhashFFI.encode(imageProvider);

Decoding

import 'package:blurhash_ffi/blurhash_ffi.dart';
import 'dart:ui' as ui;
/// You have 3 ways to decode a blurhash 
///
/// 1. Using the `BlurhashFfi` widget
/// 2. Using the `BlurhashFfiImage` ImageProvider
/// 3. Using the `BlurhashFfi.decode` static method

/// 1. Using the `BlurhashFfi` widget (same constructor as flutter_blurhash's Blurhash widget)
class BlurHashApp extends StatelessWidget {
  const BlurHashApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) => MaterialApp(
    home: Scaffold(
      appBar: AppBar(title: const Text("BlurHash")),
      body: const SizedBox.expand(
        child: Center(
          child: AspectRatio(
            aspectRatio: 1.6,
            child: BlurhashFfi(hash: "L5H2EC=PM+yV0g-mq.wG9c010J}I"),
          ),
        ),
      ),
    ),
  );
}

/// 2. Using the `BlurhashFfiImage` ImageProvider
final imageProvider = BlurhashFfiImage(hash: "L5H2EC=PM+yV0g-mq.wG9c010J}I");
class BlurHashApp2 extends StatelessWidget {
  const BlurHashApp2({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) => MaterialApp(
    home: Scaffold(
      appBar: AppBar(title: const Text("BlurHash")),
      body: const SizedBox.expand(
        child: Center(
          child: AspectRatio(
            aspectRatio: 1.6,
            child: Image(
              image: imageProvider,
              fit: BoxFit.cover, 
            ),
          ),
        ),
      ),
    ),
  );
}

/// 3. Using the `BlurhashFfi.decode` static method which returns dart:ui.Image
/// Signature 
/// static Future<ui.Image> decode(
///   String blurHash, {
///   int width = 32,
///   int height = 32,
///   int punch = 1,
/// })
/// may throw `BlurhashFFIException` if decoding fails.
final ui.Image image = await BlurhashFFI.decode("L5H2EC=PM+yV0g-mq.wG9c010J}I");

check the [example](./example/) for more details

## Project structure

* `src`: Contains the native source code, and a CmakeFile.txt file for building
  that source code into a dynamic library.

* `lib`: Contains the Dart code that defines the API of the plugin, and which
  calls into the native code using `dart:ffi`.

* platform folders (`android`, `ios`, `windows`, etc.): Contains the build files
  for building and bundling the native code library with the platform application.

## Building and bundling native code

The `pubspec.yaml` specifies FFI plugins as follows:

```yaml
  plugin:
    platforms:
      some_platform:
        ffiPlugin: true

This configuration invokes the native build for the various target platforms and bundles the binaries in Flutter applications using these FFI plugins.

This can be combined with dartPluginClass, such as when FFI is used for the implementation of one platform in a federated plugin:

  plugin:
    implements: some_other_plugin
    platforms:
      some_platform:
        dartPluginClass: SomeClass
        ffiPlugin: true

A plugin can have both FFI and method channels:

  plugin:
    platforms:
      some_platform:
        pluginClass: SomeName
        ffiPlugin: true

The native build systems that are invoked by FFI (and method channel) plugins are:

• For Android: Gradle, which invokes the Android NDK for native builds.
  • See the documentation in android/build.gradle.
• For iOS and MacOS: Xcode, via CocoaPods.
  • See the documentation in ios/blurhash_ffi.podspec.
  • See the documentation in macos/blurhash_ffi.podspec.
• For Linux and Windows: CMake.
  • See the documentation in linux/CMakeLists.txt.
  • See the documentation in windows/CMakeLists.txt.

Binding to native code

To use the native code, bindings in Dart are needed. To avoid writing these by hand, they are generated from the header file (src/blurhash_ffi.h) by package:ffigen. Regenerate the bindings by running flutter pub run ffigen --config ffigen.yaml.

Flutter help

For help getting started with Flutter, view our online documentation, which offers tutorials, samples, guidance on mobile development, and a full API reference.