A Dart implementation of the Processing API for Flutter. Processing is a software sketchbook and a language for learning how to code within the context of the visual arts.
Note: this is an experimental library that only implements a few functions from the Processing API. Class names and structure will likely change in the future. And feel free to fork and play around with the code :-)
Add the p5 package to your Flutter app. For help using packages, see Flutter's online documentation.
You need to implement the widget containing the Processing sketch, and the sketch itself.
A simple widget tree is the follwing:
import 'package:flutter/material.dart';
import "package:p5/p5.dart";
import "sketch.dart";
void main() => runApp(new MyApp());
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
@override
_MyHomePageState createState() {
return new _MyHomePageState();
}
}
class MyApp extends StatelessWidget {
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return new MaterialApp(
title: 'P5 Demo',
theme: new ThemeData(
// This is the theme of your application.
primarySwatch: Colors.blue,
),
home: new MyHomePage(title: 'P5 Demo Home Page'),
);
}
}
class _MyHomePageState extends State<MyHomePage> with SingleTickerProviderStateMixin {
MySketch sketch;
PAnimator animator;
@override
void initState() {
super.initState();
sketch = new MySketch();
// Need an animator to call the draw() method in the sketch continuously,
// otherwise it will be called only when touch events are detected.
animator = new PAnimator(this);
animator.addListener(() {
setState(() {
sketch.redraw();
});
});
animator.run();
}
@override
Widget build(BuildContext context) {
return new Scaffold(
appBar: new AppBar(title: new Text("P5 Draw!")),
backgroundColor: const Color.fromRGBO(200, 200, 200, 1.0),
body: new Center(
child:new PWidget(sketch),
),
);
}
}
The MySketch class has to extend the base PPainter class in the p5 package, and implement the setup() and draw() functions, just like in Processing sketch:
class MySketch extends PPainter {
void setup() {
size(300, 300);
}
void draw() {
background(color(255, 255, 255));
}
}Both pieces of code can be inside single dart file, or on separate files for better clarity.
A simple drawing sketch can be implemented by handling the mouse dragging, and storing the pointer positions in a list of PVector object holding the (x, y) coordinates, which are then used to draw lines:
class MySketch extends PPainter {
var strokes = new List<List<PVector>>();
void setup() {
fullScreen();
}
void draw() {
background(color(255, 255, 255));
noFill();
strokeWeight(10);
stroke(color(10, 40, 200, 60));
for (var stroke in strokes) {
beginShape();
for (var p in stroke) {
vertex(p.x, p.y);
}
endShape();
}
}
void mousePressed() {
strokes.add([new PVector(mouseX, mouseY)]);
}
void mouseDragged() {
var stroke = strokes.last;
stroke.add(new PVector(mouseX, mouseY));
}
}Notice that the size of the drawing area can be made to fill the entire app by using fullScreen(). The app should give similar results for both iOS and Android:
For help getting started with Flutter, view our online documentation.
For help on editing package code, view the documentation.
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