Change color in rive (flare) - flutter

Question

I have a .flr animation of a minion. Is it possible to change colors of his body, pants, eyes, etc dynamicaly and separately in flutter app?
PS Minion is just an example i found on rive.app .There will be another character with lots of different parts.
PPS Maybe there is a better way to make a simple animated character in flutter? For now, i have a stack with positioned colorfilterd images, but i guess it should be easier with rive.

Answer 1

Yes you can. There is an example in the Flare github:
https://github.com/2d-inc/Flare-Flutter/tree/master/example/change_color
import 'package:flare_flutter/flare_controller.dart';
import 'package:flare_flutter/flare.dart';
import 'package:flare_dart/math/mat2d.dart';
import 'package:flare_flutter/flare_actor.dart';
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
#override
_MyHomePageState createState() => _MyHomePageState();
}
List<Color> exampleColors = <Color>[Colors.red, Colors.green, Colors.blue];
class _MyHomePageState extends State<MyHomePage> with FlareController {
FlutterColorFill _fill;
void initialize(FlutterActorArtboard artboard) {
// Find our "Num 2" shape and get its fill so we can change it programmatically.
FlutterActorShape shape = artboard.getNode("Num 2");
_fill = shape?.fill as FlutterColorFill;
}
void setViewTransform(Mat2D viewTransform) {}
bool advance(FlutterActorArtboard artboard, double elapsed) {
// advance is called whenever the flare artboard is about to update (before it draws).
Color nextColor = exampleColors[_counter % exampleColors.length];
if (_fill != null) {
_fill.uiColor = nextColor;
}
// Return false as we don't need to be called again. You'd return true if you wanted to manually animate some property.
return false;
}
// We're going to use the counter to iterate the color.
int _counter = 0;
void _incrementCounter() {
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++;
// advance the controller
isActive.value = true;
});
}
#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),
),
body: FlareActor("assets/change_color_example.flr", // You can find the example project here: https://www.2dimensions.com/a/castor/files/flare/change-color-example
fit: BoxFit.contain, alignment: Alignment.center, controller: this),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: 'Increment',
child: Icon(Icons.add),
), // This trailing comma makes auto-formatting nicer for build methods.
);
}
}
If you're using the beta of Rive it's a bit different. I'm not sure if it's the best approach but I'm doing the following:
artboard.forEachComponent((child){
if (child.name == 'Fill') {
Fill fill = child;
fill.paint.color = Colors.red.withOpacity(0.25);
}
else if (child.name == 'Stroke') {
Stroke stroke = child;
stroke.paint.color = Colors.red;
}
});

Answer 2

As Kretin already outlined with the Flutter rive package it is possible even though it's beta as of writing.
To get this to work, you have to know thinks about your animation, for example the name of the shape you want to change (first), and the fill color you want to change.
Let's assume, I have an animation with a shape which name is 'Button1'.
This shape has one fill color that I'd like to change, then my code looks like this:
artboard.forEachComponent((child) {
if (child is Shape && child.name == 'Button1') {
final Shape shape = child;
shape.fills.first.paint.color = Colors.red;
}
});

Answer 3

I have tried the forEachComponent method that the other answers here mention, but it didn't work exactly like I expected. It iterated the components over and over again, spending a lot of process power and also because I was testing merging colors, it ended up merging again and again.
So I ended up checking the properties of the classes to find how to get the colors precisely and changing.
In my code, I'm changing a part of a color of linear gradients. But to get a solid color you can change
shape.fills.first.paintMutator.children.[first/last].color
to
shape.fills.first.paint.color
My code is like this:
final rootBone =
artboard.children.firstWhereOrNull((e) => e.name == 'Root Bone');
final rootBoneChildren = rootBone?.artboard?.drawables;
// Changing hair color
final hair =
rootBoneChildren?.firstWhereOrNull((e) => e.name == 'hair');
if (hair is Shape) {
((hair.fills.first.paintMutator as dynamic)?.children.first
as dynamic)
.color = AppColors.accent;
}
// Changing head color
final head =
rootBoneChildren?.firstWhereOrNull((e) => e.name == 'head');
if (head is Shape) {
final colorParts =
(head.fills.first.paintMutator as dynamic)?.children;
const mergeColor = AppColors.brown;
const timeline = 0.9;
// center
colorParts.first.color =
Color.lerp(colorParts.first.color, mergeColor, timeline);
// border
colorParts.last.color =
Color.lerp(colorParts.last.color, mergeColor, timeline);
}
ps: I'm casting as dynamic because it is a class called LinearGradient, extended from the paintMutator original class, and the class LinearGradient from rive has the same name as LinearGradient from flutter and I didn't want to use aliases everywhere in the code just because of those lines.