Joshua Rowe

Joshua Rowe


High Performance Animations and 2D Games with Flutter


SpriteWidget is a toolkit for building complex, high performance animations and 2D games with Flutter. Your sprite render tree lives inside a widget that mixes seamlessly with other Flutter and Material widgets. You can use SpriteWidget to create anything from an animated icon to a full fledged game.

This guide assumes a basic knowledge of Flutter and Dart. Get support by posting a question tagged spritewidget on StackOverflow.

You can find examples in the examples directory, or check out the complete Space Blast game.


Adding SpriteWidget to your project

SpriteWidget is available as a standard package. Just add it as a dependency to your pubspec.yaml and you are good to go.

    sdk: flutter

Creating a SpriteWidget

The first thing you need to do to use SpriteWidget is to setup a root node that is used to draw it’s contents. Any sprite nodes that you add to the root node will be rendered by the SpriteWidget. Typically, your root node is part of your app’s state. This is an example of how you can setup a custom stateful widget with a SpriteWidget:

import 'package:flutter/material.dart';
import 'package:spritewidget/spritewidget.dart';

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

class MyWidgetState extends State<MyWidget> {
  NodeWithSize rootNode;

  void initState() {
    rootNode = new NodeWithSize(const Size(1024.0, 1024.0));

  Widget build(BuildContext context) {
  	return new SpriteWidget(rootNode);

The root node that you provide the SpriteWidget is a NodeWithSize, the size of the root node defines the coordinate system used by the SpriteWidget. By default the SpriteWidget uses letterboxing to display its contents. This means that the size that you give the root node will determine how the SpriteWidget’s contents will be scaled to fit. If it doesn’t fit perfectly in the area of the widget, either its top and bottom or the left and right side will be trimmed. You can optionally pass in a parameter to the SpriteWidget for other scaling options depending on your needs.

When you have added the SpriteWidget to your app’s build method it will automatically start running animations and handling user input. There is no need for any other extra setup.

Adding objects to your node graph

Your SpriteWidget manages a node graph, the root node is the NodeWithSize that is passed in to the SpriteWidget when it’s created. To render sprites, particles systems, or any other objects simply add them to the node graph.

Each node in the node graph has a transform. The transform is inherited by its children, this makes it possible to build more complex structures by grouping objects together as children to a node and then manipulating the parent node. For example the following code creates a car sprite with two wheels attached to it. The car is added to the root node.

Sprite car = new Sprite.fromImage(carImage);
Sprite frontWheel = new Sprite.fromImage(wheelImage);
Sprite rearWheel = new Sprite.fromImage(wheelImage);

frontWheel.position = const Offset(100, 50);
rearWheel.position = const Offset(-100, 50);



You can manipulate the transform by setting the position, rotation, scale, and skew properties.

Sprites, textures, and sprite sheets

To load image resources, the easiest way is to use the ImageMap class. The ImageMap can load one or multiple images at once.

The Image class isn’t automatically imported through flutter/material, so you may need to add an import at the top of your file.

import 'dart:ui' as ui show Image;

Now you can load images using the ImageMap. Note that the loading methods are asynchronous, so this example code will need to go in an asynch method. For a full example of loading images see the Weather Demo.

ImageMap images = new ImageMap(rootBundle);

// Load a single image
ui.Image image = await images.loadImage('assets/my_image.png');

// Load multiple images
await images.load(<String>[

// Access a loaded image from the ImageMap
image = images['assets/image_0.png'];

The most common node type is the Sprite node. A sprite simply draws an image to the screen. Sprites can be drawn from Image objects or SpriteTexture objects. A texture is a part of an Image. Using a SpriteSheet you can pack several texture elements within a single image. This saves space in the device’s gpu memory and also make drawing faster. Currently SpriteWidget supports sprite sheets in json format and produced with a tool such as TexturePacker. It’s uncommon to manually edit the sprite sheet files. You can create a SpriteSheet with a definition in json and an image:

SpriteSheet sprites = new SpriteSheet(myImage, jsonCode);
SpriteTexture texture = sprites['texture.png'];

The frame cycle

Each time a new frame is rendered to screen SpriteWidget will perform a number of actions. Sometimes when creating more advanced interactive animations or games, the order in which these actions are performed may matter.

This is the order things will happen:

  1. Handle input events
  2. Run animation motions
  3. Call update functions on nodes
  4. Apply constraints
  5. Render the frame to screen

Read more about each of the different phases below.

Handling user input

You can subclass any node type to handle touches. To receive touches, you need to set the userInteractionEnabled property to true and override the handleEvent method. If the node you are subclassing doesn’t have a size, you will also need to override the isPointInside method.

class EventHandlingNode extends NodeWithSize {
  EventHandlingNode(Size size) : super(size) {
    userInteractionEnabled = true;

  @override handleEvent(SpriteBoxEvent event) {
    if (event.type == PointerDownEvent)
    else if (event.type == PointerMoveEvent)

    return true;

If you want your node to receive multiple touches, set the handleMultiplePointers property to true. Each touch down or dragged touch will generate a separate call to the handleEvent method, you can distinguish each touch by its pointer property.

Animating using motions

SpriteWidget provides easy to use functions for animating nodes through motions. You can combine simple motion blocks to create more complex animations.

To execute a motion animation you first build the motion itself, then pass it to the run method of a nodes motion manager (see the Tweens section below for an example).


Tweens are the simplest building block for creating an animation. It will interpolate a value or property over a specified time period. You provide the MotionTween class with a setter function, its start and end value, and the duration for the tween.

After creating a tween, execute it by running it through a node’s motion manager.

Node myNode = new Node();

MotionTween myTween = new MotionTween<Offset> (
  (a) => myNode.position = a,,
  const Offset(100.0, 0.0),

You can animate values of different types, such as floats, points, rectangles, and even colors. You can also optionally provide the MotionTween class with an easing function.


When you need to play two or more motions in a sequence, use the MotionSequence class:

MotionSequence sequence = new MotionSequence([


Use MotionGroup to play motions in parallel:

MotionGroup group = new MotionGroup([


You can loop any motion, either a fixed number of times, or until the end of times:

MotionRepeat repeat = new MotionRepeat(loopedMotion, 5);

MotionRepeatForever longLoop = new MotionRepeatForever(loopedMotion);


It’s possible to create more complex motions by composing them in any way:

MotionSequence complexMotion = new MotionSequence([
  new MotionRepeat(myLoop, 2),
  new MotionGroup([

Handle update events

Each frame, update events are sent to each node in the current node tree. Override the update method to manually do animations or to perform game logic.

MyNode extends Node {
  update(double dt) {
    // Move the node at a constant speed
  	position += new Offset(dt * 1.0, 0.0);

Defining constraints

Constraints are used to constrain properties of nodes. They can be used to position nodes relative other nodes, or adjust the rotation or scale. You can apply more than one constraint to a single node.

For example, you can use a constraint to make a node follow another node at a specific distance with a specified dampening. The dampening will smoothen out the following node’s movement.

followingNode.constraints = [
  new ConstraintPositionToNode(
    offset: const Offset(0.0, 100.0),
    dampening: 0.5

Constraints are applied at the end of the frame cycle. If you need them to be applied at any other time, you can directly call the applyConstraints method of a Node object.

Perform custom drawing

SpriteWidget provides a default set of drawing primitives, but there are cases where you may want to perform custom drawing. To do this you will need to subclass either the Node or NodeWithSize class and override the paint method:

class RedCircle extends Node {

  double radius;

  void paint(Canvas canvas) {
      new Paint()..color = const Color(0xffff0000)

If you are overriding a NodeWithSize you may want to call applyTransformForPivot before starting drawing to account for the node’s pivot point. After the call the coordinate system is setup so you can perform drawing starting at origo to the size of the node.

void paint(Canvas canvas) {

    new Rect.fromLTWH(0.0, 0.0, size.width, size.height),

Add effects using particle systems

Particle systems are great for creating effects such as rain, smoke, or fire. It’s easy to setup a particle system, but there are very many properties that can be tweaked. The best way of to get a feel for how they work is to simply play around with the them.

This is an example of how a particle system can be created, configured, and added to the scene:

ParticleSystem particles = new ParticleSystem(
  posVar: const Point(100, 100.0),
  startSize: 1.0,
  startSizeVar: 0.5,
  endSize: 2.0,
  endSizeVar: 1.0,
  life: 1.5 * distance,
  lifeVar: 1.0 * distance


Download Details:

Author: spritewidget


#flutter #dart #mobile-apps #game2d

What is GEEK

Buddha Community

High Performance Animations and 2D Games with Flutter

Google's Flutter 1.20 stable announced with new features - Navoki

Flutter Google cross-platform UI framework has released a new version 1.20 stable.

Flutter is Google’s UI framework to make apps for Android, iOS, Web, Windows, Mac, Linux, and Fuchsia OS. Since the last 2 years, the flutter Framework has already achieved popularity among mobile developers to develop Android and iOS apps. In the last few releases, Flutter also added the support of making web applications and desktop applications.

Last month they introduced the support of the Linux desktop app that can be distributed through Canonical Snap Store(Snapcraft), this enables the developers to publish there Linux desktop app for their users and publish on Snap Store.  If you want to learn how to Publish Flutter Desktop app in Snap Store that here is the tutorial.

Flutter 1.20 Framework is built on Google’s made Dart programming language that is a cross-platform language providing native performance, new UI widgets, and other more features for the developer usage.

Here are the few key points of this release:

Performance improvements for Flutter and Dart

In this release, they have got multiple performance improvements in the Dart language itself. A new improvement is to reduce the app size in the release versions of the app. Another performance improvement is to reduce junk in the display of app animation by using the warm-up phase.


If your app is junk information during the first run then the Skia Shading Language shader provides for pre-compilation as part of your app’s build. This can speed it up by more than 2x.

Added a better support of mouse cursors for web and desktop flutter app,. Now many widgets will show cursor on top of them or you can specify the type of supported cursor you want.

Autofill for mobile text fields

Autofill was already supported in native applications now its been added to the Flutter SDK. Now prefilled information stored by your OS can be used for autofill in the application. This feature will be available soon on the flutter web.


A new widget for interaction

InteractiveViewer is a new widget design for common interactions in your app like pan, zoom drag and drop for resizing the widget. Informations on this you can check more on this API documentation where you can try this widget on the DartPad. In this release, drag-drop has more features added like you can know precisely where the drop happened and get the position.

Updated Material Slider, RangeSlider, TimePicker, and DatePicker

In this new release, there are many pre-existing widgets that were updated to match the latest material guidelines, these updates include better interaction with Slider and RangeSliderDatePicker with support for date range and time picker with the new style.


New pubspec.yaml format

Other than these widget updates there is some update within the project also like in pubspec.yaml file format. If you are a flutter plugin publisher then your old pubspec.yaml  is no longer supported to publish a plugin as the older format does not specify for which platform plugin you are making. All existing plugin will continue to work with flutter apps but you should make a plugin update as soon as possible.

Preview of embedded Dart DevTools in Visual Studio Code

Visual Studio code flutter extension got an update in this release. You get a preview of new features where you can analyze that Dev tools in your coding workspace. Enable this feature in your vs code by _dart.previewEmbeddedDevTools_setting. Dart DevTools menu you can choose your favorite page embed on your code workspace.

Network tracking

The updated the Dev tools comes with the network page that enables network profiling. You can track the timings and other information like status and content type of your** network calls** within your app. You can also monitor gRPC traffic.

Generate type-safe platform channels for platform interop

Pigeon is a command-line tool that will generate types of safe platform channels without adding additional dependencies. With this instead of manually matching method strings on platform channel and serializing arguments, you can invoke native class and pass nonprimitive data objects by directly calling the Dartmethod.

There is still a long list of updates in the new version of Flutter 1.2 that we cannot cover in this blog. You can get more details you can visit the official site to know more. Also, you can subscribe to the Navoki newsletter to get updates on these features and upcoming new updates and lessons. In upcoming new versions, we might see more new features and improvements.

You can get more free Flutter tutorials you can follow these courses:

#dart #developers #flutter #app developed #dart devtools in visual studio code #firebase local emulator suite in flutter #flutter autofill #flutter date picker #flutter desktop linux app build and publish on snapcraft store #flutter pigeon #flutter range slider #flutter slider #flutter time picker #flutter tutorial #flutter widget #google flutter #linux #navoki #pubspec format #setup flutter desktop on windows

Terry  Tremblay

Terry Tremblay


What is Flutter and why you should learn it?

Flutter is an open-source UI toolkit for mobile developers, so they can use it to build native-looking** Android and iOS** applications from the same code base for both platforms. Flutter is also working to make Flutter apps for Web, PWA (progressive Web-App) and Desktop platform (Windows,macOS,Linux).


Flutter was officially released in December 2018. Since then, it has gone a much stronger flutter community.

There has been much increase in flutter developers, flutter packages, youtube tutorials, blogs, flutter examples apps, official and private events, and more. Flutter is now on top software repos based and trending on GitHub.

Flutter meaning?

What is Flutter? this question comes to many new developer’s mind.


Flutter means flying wings quickly, and lightly but obviously, this doesn’t apply in our SDK.

So Flutter was one of the companies that were acquired by **Google **for around $40 million. That company was based on providing gesture detection and recognition from a standard webcam. But later when the Flutter was going to release in alpha version for developer it’s name was Sky, but since Google already owned Flutter name, so they rename it to Flutter.

Where Flutter is used?

Flutter is used in many startup companies nowadays, and even some MNCs are also adopting Flutter as a mobile development framework. Many top famous companies are using their apps in Flutter. Some of them here are





Reflectly app

Reflectly app

Abbey Road Studios

Abbey Road Studios

and many more other apps. Mobile development companies also adopted Flutter as a service for their clients. Even I was one of them who developed flutter apps as a freelancer and later as an IT company for mobile apps.

Flutter as a service

#dart #flutter #uncategorized #flutter framework #flutter jobs #flutter language #flutter meaning #flutter meaning in hindi #google flutter #how does flutter work #what is flutter

Adobe XD plugin for Flutter with CodePen Tutorial

Recently Adobe XD releases a new version of the plugin that you can use to export designs directly into flutter widgets or screens. Yes, you read it right, now you can make and export your favorite design in Adobe XD and export all the design in the widget form or as a full-screen design, this can save you a lot of time required in designing.

What we will do?
I will make a simple design of a dialogue box with a card design with text over it as shown below. After you complete this exercise you can experiment with the UI. You can make your own components or import UI kits available with the Adobe XD.

#developers #flutter #adobe xd design export to flutter #adobe xd flutter code #adobe xd flutter code generator - plugin #adobe xd flutter plugin #adobe xd flutter plugin tutorial #adobe xd plugins #adobe xd to flutter #adobe xd tutorial #codepen for flutter.

Autumn  Blick

Autumn Blick


Game Development with .NET

We’ve launched a new Game Development with .NET section on our site. It’s designed for current .NET developers to explore all the choices available to them when developing games. It’s also designed for new developers trying to learn how to use .NET by making games. We’ve also launched a new game development Learn portal for .NET filled with tutorials, videos, and documentation provided by Microsoft and others in the .NET game development community. Finally, we launched a step-by-step Unity get-started tutorial that will get you started with Unity and writing C## scripts for it in no time. We are excited to show you what .NET has to offer to you when making games. .NET is also part of Microsoft Game Stack, a comprehensive suite of tools and services just for game development.

A picture of a game controller

.NET for game developers

.NET is cross-platform. With .NET you can target over 25+ different platforms with a single code base. You can make games for, but not limited to, Windows, macOS, Linux, Android, iOS, Xbox, PlayStation, Nintendo, and mixed reality devices.

C## is the most popular programming language in game development. The wider .NET community is also big. There is no lack of expertise and support you can find from individuals and user groups, locally or online.

.NET does not just cover building your game. You can also use it to build your game’s website with ASP.NET, your mobile app using Xamarin, and even do remote rendering with Microsoft Azure. Your skills will transfer across the entire game development pipeline.

logos of some gaming platforms supported by .NET

Available game engines

The first step to developing games in .NET is to choose a game engine. You can think of engines as the frameworks and tools you use for developing your game. There are many game engines that use .NET and they differ widely. Some of the engines are commercial and some are completely royalty free and open source. I am excited to see some of them planning to adopt .NET 5 soon. Just choose the engine that better works for you and your game. Would you like to read a blog post to help you learn about .NET game engines, and which one would be best for you? core #azure #c# #game development #azure #cryengine #game developers #game development #game development with .net #game engines #games #monogame #playfab #stride #unity #visual studio #waveengine

Carmelo  Hauck

Carmelo Hauck


Animations in Flutter - 3. Cloning Animation

In this video tutorial, we are going to build a simple animation using flutter. In this animation, two circle containers overlap each other, the animation will separate these circles and make it look like a single container is cloning itself.

Source code:

Let’s start our animation app. :)

#flutter #animations in flutte #cloning animation #animations