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dart(freeform-gradient): feat: implementation

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Signed-off-by: prescientmoon <git@moonythm.dev>
This commit is contained in:
Matei Adriel 2021-08-05 16:25:35 +03:00 committed by prescientmoon
parent 5bbf425e2f
commit 8294895837
Signed by: prescientmoon
SSH key fingerprint: SHA256:UUF9JT2s8Xfyv76b8ZuVL7XrmimH4o49p4b+iexbVH4
4 changed files with 198 additions and 163 deletions
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56
dart/freeform-gradient/README.md
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@ -1,16 +1,10 @@
# Hello World application with Flutter + Nix
# Flutter freeform gradiant
This is a demonstration project to show usage of Flutter with Nix.
## Getting Started
If you have `direnv` installed, run:
```sh
direnv allow
```
Otherwise, enter in the `nix-shell`:
Enter in the `nix-shell`:
```sh
nix-shell
@ -29,49 +23,3 @@ flutter run
```
If you have any issue, you can run `flutter doctor` to get a diagnostic and potential solution to fix your issues.
## How to use it with your projects
Create a `shell.nix` file with this content:
```nix
{ pkgs ? import <nixpkgs> {} }:
let
flutter = (import (builtins.fetchTarball
"https://github.com/babariviere/nixpkgs/archive/flutter-init.tar.gz") {}).flutter; # this will be replaced when merged into NixOS
in pkgs.mkShell {
buildInputs = [ flutter ];
}
```
After this, enter into your nix-shell and you are good to go.
## Updating
### To update the whole environment, do the following in order:
- `niv init` will update nix/sources.nix if a new one is available
- Make sure you have a backup of your nix/sources.json. If you're not in a git repo or use another vcs: `cp nix/sources.json nix/sources.json.bak`
- `niv update` will update sources.json i.e. your version of nixpkgs used in this environment
- you may need to edit nix/android.nix if any of the attributes in there can't be found after this.
- `direnv reload` will rebuild/reload your environment (may not be necessary if it automatically reloads)
- alternatively, run `nix-shell` again (?)
- `flutter packages update` to update flutter/dart packages and get rid of the warning that you're using a different version of flutter than what was last referenced
## Global install
If you want to install `flutter` on your system, add this to your `/etc/nixos/configuration.nix`:
```nix
{
environment.systemPackages = [
(import (builtins.fetchTarball
"https://github.com/babariviere/nixpkgs/archive/flutter-init.tar.gz") {}).flutter
];
}
```
## Have an issue ?
Create an issue on this repository with your issue and I will try to help you as much as I can !

285
dart/freeform-gradient/lib/main.dart
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@ -1,111 +1,212 @@
import 'dart:math';
import 'package:flutter/material.dart';
import 'dart:ui' as ui;
import 'dart:async';
import 'dart:typed_data';
import 'package:vector_math/vector_math.dart' as vector;
void main() => runApp(MyApp());
void main() => runApp(Root());
class MyApp extends StatelessWidget {
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
// This is the theme of your application.
//
// Try running your application with "flutter run". You'll see the
// application has a blue toolbar. Then, without quitting the app, try
// changing the primarySwatch below to Colors.green and then invoke
// "hot reload" (press "r" in the console where you ran "flutter run",
// or simply save your changes to "hot reload" in a Flutter IDE).
// Notice that the counter didn't reset back to zero; the application
// is not restarted.
primarySwatch: Colors.blue,
),
home: MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
// This widget is the home page of your application. It is stateful, meaning
// that it has a State object (defined below) that contains fields that affect
// how it looks.
// This class is the configuration for the state. It holds the values (in this
// case the title) provided by the parent (in this case the App widget) and
// used by the build method of the State. Fields in a Widget subclass are
// always marked "final".
final String title;
class Root extends StatefulWidget {
const Root({
Key key,
}) : super(key: key);
@override
_MyHomePageState createState() => _MyHomePageState();
RootState createState() => RootState();
}
class _MyHomePageState extends State<MyHomePage> {
int _counter = 0;
class RootState extends State<Root> {
double angle = 0;
void _incrementCounter() {
@override
initState() {
super.initState();
Timer.periodic(Duration(milliseconds: 10), (timer) {
setState(() {
// This call to setState tells the Flutter framework that something has
// changed in this State, which causes it to rerun the build method below
// so that the display can reflect the updated values. If we changed
// _counter without calling setState(), then the build method would not be
// called again, and so nothing would appear to happen.
_counter++;
angle += 0.04;
});
});
}
@override
Widget build(BuildContext context) {
// This method is rerun every time setState is called, for instance as done
// by the _incrementCounter method above.
//
// The Flutter framework has been optimized to make rerunning build methods
// fast, so that you can just rebuild anything that needs updating rather
// than having to individually change instances of widgets.
return Scaffold(
appBar: AppBar(
// Here we take the value from the MyHomePage object that was created by
// the App.build method, and use it to set our appbar title.
title: Text(widget.title),
return MaterialApp(
title: 'Custom gradient',
theme: ThemeData(
primarySwatch: Colors.purple,
),
body: Center(
// Center is a layout widget. It takes a single child and positions it
// in the middle of the parent.
child: Column(
// Column is also a layout widget. It takes a list of children and
// arranges them vertically. By default, it sizes itself to fit its
// children horizontally, and tries to be as tall as its parent.
//
// Invoke "debug painting" (press "p" in the console, choose the
// "Toggle Debug Paint" action from the Flutter Inspector in Android
// Studio, or the "Toggle Debug Paint" command in Visual Studio Code)
// to see the wireframe for each widget.
//
// Column has various properties to control how it sizes itself and
// how it positions its children. Here we use mainAxisAlignment to
// center the children vertically; the main axis here is the vertical
// axis because Columns are vertical (the cross axis would be
// horizontal).
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text(
'You have pushed the button this many times:',
home: MyHomePage(
title: 'Multi point gradient',
config: MultiGradientConfig(
distanceScaling: 1,
blendStrength: 2,
points: [
MultiGradientPoint(
color: Colors.yellow,
intensity: 1.0,
position: vector.Vector2(
1.0 / 2 + cos(angle) * 0.3, 1.0 / 2 + sin(angle) * 0.3),
),
Text(
'$_counter',
style: Theme.of(context).textTheme.display1,
),
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: 'Increment',
child: Icon(Icons.add),
), // This trailing comma makes auto-formatting nicer for build methods.
MultiGradientPoint(
color: Color(0xff6E10AB),
intensity: 1,
position: vector.Vector2(0.1, 0.09)),
MultiGradientPoint(
color: Color(0xff041E1C),
intensity: 2,
position: vector.Vector2(0.84, 0.14)),
MultiGradientPoint(
color: Color(0xff015BBB),
intensity: 1,
position: vector.Vector2(0.07, 0.93)),
MultiGradientPoint(
color: Color(0xff06A599),
intensity: 1,
position: vector.Vector2(0.9, 0.94))
])),
);
}
}
class MyHomePage extends StatelessWidget {
MyHomePage({Key key, this.title, this.config}) : super(key: key);
final String title;
final MultiGradientConfig config;
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(title),
),
body: Center(
child: FutureBuilder<ui.Image>(
future: generateImage(MediaQuery.of(context).size, config),
builder: (context, snapshot) {
if (snapshot.hasData) {
MediaQueryData query = MediaQuery.of(context);
return CustomPaint(
child: Container(
width: query.size.width,
height: query.size.height,
),
painter: ImagePainter(image: snapshot.data));
}
return Text("Generating image");
},
)),
);
}
}
class ImagePainter extends CustomPainter {
ui.Image image;
ImagePainter({this.image});
@override
void paint(Canvas canvas, Size size) {
canvas.drawImage(image, Offset.zero, Paint());
}
@override
bool shouldRepaint(ImagePainter oldDelegate) {
return oldDelegate.image != image;
}
}
/// Generates a [ui.Image] with certain pixel data
Future<ui.Image> generateImage(Size size, MultiGradientConfig config) async {
int width = size.width.ceil();
int height = size.height.ceil();
var completer = Completer<ui.Image>();
Int32List pixels = Int32List(width * height);
for (var x = 0; x < width; x++) {
for (var y = 0; y < height; y++) {
int index = y * width + x;
pixels[index] = generatePixel(x, y, size, config);
}
}
ui.decodeImageFromPixels(
pixels.buffer.asUint8List(),
width,
height,
ui.PixelFormat.bgra8888,
(ui.Image img) {
completer.complete(img);
},
);
return completer.future;
}
class MultiGradientPoint {
double intensity;
vector.Vector4 color;
vector.Vector2 position;
MultiGradientPoint({Color color, this.position, this.intensity = 1}) {
this.color = vector.Vector4(color.red.toDouble(), color.green.toDouble(),
color.blue.toDouble(), color.opacity);
}
}
class MultiGradientConfig {
List<MultiGradientPoint> points;
double distanceScaling;
double blendStrength;
double opacityMultiplier = 1;
MultiGradientConfig(
{this.points,
this.distanceScaling = 1,
this.blendStrength = 3,
this.opacityMultiplier = 1});
}
double clamp(double min, double max, double value) {
if (value < min) return min;
if (value > max) return max;
return value;
}
/// Main area of interest, this function will
/// return color for each particular color on our [ui.Image]
int generatePixel(int x, int y, Size size, MultiGradientConfig config) {
vector.Vector4 color = vector.Vector4(0, 0, 0, 0);
double scale = 0;
var current = vector.Vector2(x.toDouble(), y.toDouble());
current.divide(vector.Vector2(size.width, size.height));
for (var i = 0; i < config.points.length; i++) {
MultiGradientPoint point = config.points[i];
var distance = pow(
1 - point.position.distanceTo(current) / config.distanceScaling,
config.blendStrength);
var multiplier = distance * point.intensity;
scale += multiplier;
color += point.color.scaled(multiplier);
}
if (scale != 0) {
color.scale(1 / scale);
}
return Color.fromRGBO(color.x.toInt(), color.y.toInt(), color.z.toInt(),
color.w * config.opacityMultiplier)
.value;
}

14
dart/freeform-gradient/pubspec.yaml
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@ -1,16 +1,6 @@
name: hello_world
description: A new Flutter project.
# The following defines the version and build number for your application.
# A version number is three numbers separated by dots, like 1.2.43
# followed by an optional build number separated by a +.
# Both the version and the builder number may be overridden in flutter
# build by specifying --build-name and --build-number, respectively.
# In Android, build-name is used as versionName while build-number used as versionCode.
# Read more about Android versioning at https://developer.android.com/studio/publish/versioning
# In iOS, build-name is used as CFBundleShortVersionString while build-number used as CFBundleVersion.
# Read more about iOS versioning at
# https://developer.apple.com/library/archive/documentation/General/Reference/InfoPlistKeyReference/Articles/CoreFoundationKeys.html
version: 1.0.0+1
environment:
@ -20,21 +10,17 @@ dependencies:
flutter:
sdk: flutter
# The following adds the Cupertino Icons font to your application.
# Use with the CupertinoIcons class for iOS style icons.
cupertino_icons: ^0.1.2
dev_dependencies:
flutter_test:
sdk: flutter
# For information on the generic Dart part of this file, see the
# following page: https://dart.dev/tools/pub/pubspec
# The following section is specific to Flutter.
flutter:
# The following line ensures that the Material Icons font is
# included with your application, so that you can use the icons in
# the material Icons class.

2
dart/freeform-gradient/test/widget_test.dart
View file

@ -13,7 +13,7 @@ import 'package:hello_world/main.dart';
void main() {
testWidgets('Counter increments smoke test', (WidgetTester tester) async {
// Build our app and trigger a frame.
await tester.pumpWidget(MyApp());
await tester.pumpWidget(Root());
// Verify that our counter starts at 0.
expect(find.text('0'), findsOneWidget);