A Flutter widget that paints an image and moves it at a slower speed than the main scrolling content.

demo.gif

Installation

Add dependency to your pubspec.yaml:

dependencies:
  parallax_image: [latest version]

Usage

ParallaxImage can be used with any Scrollable (ListView for instance). When created, it subscribes to scroll updates on nearest Scrollable ancestor. It is also possible to specify custom ScrollController in which case this widget subscribes to updates on ScrollController.position (assumes that controller is attached to only one Scrollable).

class MyWidget extends StatefulWidget {
  @override
  MyWidgetState createState() => new MyWidgetState();
}

class MyWidgetState extends State<MyWidget> {
  final _controller = new ScrollController();

  @override
  Widget build(BuildContext context) {
    return new ListView(controller: _controller, children: [
      new ParallaxImage(
        image: new AssetImage('images/january.jpg'),
        // Extent of this widget in scroll direction.
        // In this case it is vertical scroll so extent defines
        // the height of this widget.
        // The image is scaled with BoxFit.fitWidth which makes it
        // occupy full width of this widget.
        // After image is scaled it should normally have height greater
        // than this value to allow for parallax effect to be
        // visible.
        extent: 100.0,
        // Optionally specify child widget.
        child: new Text('January'),
        // Optinally specify scroll controller.
        controller: _controller,
      ),
      // ...add more list items
    ]);
  }
}

See example/ folder for a complete demo.

Features and bugs

Please file feature requests and bugs at the issue tracker.

Libraries

parallax_image
ParallaxImage paints an image and moves it at a slower speed than the main scrolling content.

Dart

dart:ui
Built-in types and core primitives for a Flutter application. [...]

Core

dart:async
Support for asynchronous programming, with classes such as Future and Stream. [...]
dart:collection
Classes and utilities that supplement the collection support in dart:core. [...]
dart:convert
Encoders and decoders for converting between different data representations, including JSON and UTF-8. [...]
dart:core
Built-in types, collections, and other core functionality for every Dart program. [...]
dart:developer
Interact with developer tools such as the debugger and inspector. [...]
dart:math
Mathematical constants and functions, plus a random number generator. [...]
dart:typed_data
Lists that efficiently handle fixed sized data (for example, unsigned 8 byte integers) and SIMD numeric types. [...]

VM

dart:io
File, socket, HTTP, and other I/O support for non-web applications. [...]
dart:isolate
Concurrent programming using isolates: independent workers that are similar to threads but don't share memory, communicating only via messages. [...]