add flare_flutter.dart entrypoint, add FlareSpammerActor, FlareProgressController

flare_flutter/lib/flare_flutter.dart

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+/// Flare offers powerful realtime vector design and animation for app
+/// and game designers alike. The primary goal of Flare is to allow designers
+/// to work directly with assets that run in their final product, eliminating
+/// the need to redo that work in code.
+
+library flare_flutter;
+
+export 'package:flare_dart/math/mat2d.dart';
+
+export 'flare.dart';
+export 'flare_actor.dart';
+export 'flare_controller.dart';
+export 'flare_controls.dart';
+export 'flare_progress_controller.dart';
+export 'flare_spammer_actor.dart';

flare_flutter/lib/flare_progress_controller.dart

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+import 'package:flare_dart/math/mat2d.dart';
+
+import 'flare.dart';
+import 'flare_controller.dart';
+
+/// A naiive controller that allows you to scrub through a single animation.
+/// Useful for wiring up progress bars or scroll based animations.
+class FlareProgressController extends FlareController {
+  FlareProgressController(this.animation);
+
+  final String animation;
+
+  FlutterActorArtboard _artboard;
+  ActorAnimation _animation;
+
+  @override
+  bool advance(FlutterActorArtboard artboard, double elapsed) {
+    return false;
+  }
+
+  @override
+  void initialize(FlutterActorArtboard artboard) {
+    _artboard = artboard;
+    if (_artboard != null) {
+      _animation = artboard.getAnimation(animation);
+
+      if (_animation != null) {
+        _animation.apply(0.0, _artboard, 1.0);
+      }
+    }
+  }
+
+  /// Updates the animation progress and triggers a render
+  void update(double t) {
+    if (_animation != null) {
+      final time = _animation.duration * t;
+      _animation.apply(time, _artboard, 1.0);
+    }
+  }
+
+  @override
+  void setViewTransform(Mat2D viewTransform) {}
+}

flare_flutter/lib/flare_spammer_actor.dart

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+import 'package:flare_flutter/flare.dart';
+import 'package:flare_flutter/flare_render_box.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter/rendering.dart';
+import 'package:flare_dart/math/mat2d.dart';
+import 'package:flare_dart/math/aabb.dart';
+
+/// Triggers a [FlareSpammerActor] to fire an animation
+class FlareSpammerController extends ChangeNotifier {
+  void trigger() {
+    notifyListeners();
+  }
+}
+
+/// Allows spamming of multiple animations simultaneously. Useful for
+/// firing multiple like animations simultaneously similar to hearts
+/// in Facebook live streams.
+class FlareSpammerActor extends LeafRenderObjectWidget {
+  const FlareSpammerActor(
+    this.filename, {
+    @required this.animationBuilder,
+    @required this.controller,
+    this.fit = BoxFit.contain,
+    this.alignment = Alignment.center,
+    this.snapToEnd = false,
+    this.artboard,
+  });
+
+  /// Name of the Flare file to be loaded from the AssetBundle.
+  final String filename;
+
+  /// The name of the artboard to display.
+  final String artboard;
+
+  /// The name of the animation to play. Provides the number of currently
+  /// playing animations on screen.
+  final String Function(int count) animationBuilder;
+
+  /// When true, the animation will be applied at the end of its duration.
+  final bool snapToEnd;
+
+  /// The BoxFit strategy used to scale the Flare content into the
+  /// bounds of this widget.
+  final BoxFit fit;
+
+  /// The alignment that will be applied in conjuction to the [fit] to align
+  /// the Flare content within the bounds of this widget.
+  final Alignment alignment;
+
+  final FlareSpammerController controller;
+
+  @override
+  RenderObject createRenderObject(BuildContext context) {
+    return _FlareSpammerRenderObject(animationBuilder)
+      ..assetBundle = DefaultAssetBundle.of(context)
+      ..filename = filename
+      ..fit = fit
+      ..alignment = alignment
+      ..controller = controller;
+  }
+
+  @override
+  void updateRenderObject(
+      BuildContext context, covariant _FlareSpammerRenderObject renderObject) {
+    renderObject
+      ..assetBundle = DefaultAssetBundle.of(context)
+      ..filename = filename
+      ..fit = fit
+      ..alignment = alignment
+      ..controller = controller;
+  }
+
+  @override
+  void didUnmountRenderObject(
+      covariant _FlareSpammerRenderObject renderObject) {
+    renderObject.dispose();
+  }
+}
+
+class _RepaintAnimation {
+  final ActorAnimation animation;
+  double time = 0.0;
+  void apply(FlutterActorArtboard artboard) {
+    animation.apply(time, artboard, 1.0);
+  }
+
+  double get duration => animation.duration;
+  bool get isDone => time >= animation.duration;
+  bool get hasAnimation => animation != null;
+
+  _RepaintAnimation(this.animation);
+}
+
+/// Does the heavy lifting
+class _FlareSpammerRenderObject extends FlareRenderBox {
+  _FlareSpammerRenderObject(this.animationBuilder);
+
+  final String Function(int) animationBuilder;
+
+  String _filename;
+  FlutterActor _actor;
+  FlareSpammerController _controller;
+
+  FlareSpammerController get controller => _controller;
+  set controller(FlareSpammerController value) {
+    if (_controller == value) {
+      return;
+    }
+    _controller = value;
+    _controller.addListener(fireHeart);
+  }
+
+  void fireHeart() {
+    final newAnimation = _RepaintAnimation(
+      _artboard?.getAnimation(
+        animationBuilder(_repaintAnimations.length),
+      ),
+    );
+
+    if (newAnimation.hasAnimation) {
+      _repaintAnimations.add(newAnimation);
+    }
+  }
+
+  final List<_RepaintAnimation> _repaintAnimations = [];
+
+  FlutterActorArtboard _artboard;
+  AABB _setupAABB;
+
+  void updateBounds() {
+    if (_artboard != null) {
+      _setupAABB = _artboard.artboardAABB();
+    }
+  }
+
+  /// We're playing if we're not paused and our controller is active (or
+  /// there's no controller) or there are animations running.
+  @override
+  bool get isPlaying => _repaintAnimations.isNotEmpty;
+
+  @override
+  void onUnload() {
+    _repaintAnimations.clear();
+    controller?.removeListener(fireHeart);
+  }
+
+  String get filename => _filename;
+  set filename(String value) {
+    if (value == _filename) {
+      return;
+    }
+    _filename = value;
+
+    if (_filename == null) {
+      markNeedsPaint();
+    }
+    // file will change, let's clear out old animations.
+    _repaintAnimations.clear();
+    load();
+  }
+
+  bool _instanceArtboard() {
+    if (_actor == null || _actor.artboard == null) {
+      return false;
+    }
+    FlutterActorArtboard artboard =
+        _actor.artboard.makeInstance() as FlutterActorArtboard;
+    artboard.initializeGraphics();
+    _artboard = artboard;
+    _artboard.advance(0.0);
+    updateBounds();
+    markNeedsPaint();
+    return true;
+  }
+
+  @override
+  Future<void> load() async {
+    if (_filename == null) {
+      return;
+    }
+    _actor = await loadFlare(_filename);
+    if (_actor == null || _actor.artboard == null) {
+      return;
+    }
+    _instanceArtboard();
+  }
+
+  @override
+  void advance(double elapsedSeconds) {
+    // advance just moves every animation forward
+    if (isPlaying) {
+      for (final _RepaintAnimation animation in _repaintAnimations) {
+        animation.time += elapsedSeconds;
+      }
+    }
+
+    if (_artboard != null) {
+      _artboard.advance(elapsedSeconds);
+    }
+  }
+
+  @override
+  AABB get aabb => _setupAABB;
+
+  @override
+  void prePaint(Canvas canvas, Offset offset) {
+    // disable clipping for now
+    //   canvas.clipRect(offset & size);
+  }
+
+  @override
+  void paintFlare(Canvas canvas, Mat2D viewTransform) {
+    if (_artboard == null) {
+      return;
+    }
+
+    // Apply, paint, and prune.
+    List<_RepaintAnimation> prune = [];
+    for (final _RepaintAnimation animation in _repaintAnimations) {
+      animation.apply(_artboard);
+      // Don't have a sense of elapsed time here, so just pass 0 for time.
+      _artboard.advance(0);
+      _artboard.draw(canvas);
+      if (animation.isDone) {
+        prune.add(animation);
+      }
+    }
+    for (final _RepaintAnimation animation in prune) {
+      _repaintAnimations.remove(animation);
+    }
+  }
+}