flutter_svga_easyplayer

Play SVGA animations in Flutter with one widget. Caching, precaching, sound, loading states and typed errors are built in.

Features

• One widget. SVGAEasyPlayer downloads, caches, decodes, plays and cleans up.
• Nothing fails silently. Every failure is a typed SVGAException, with a placeholder and an error widget to show while loading or when it fails.
• Safe caching. Files are stored only after they decode, written atomically and verified by checksum. A bad entry replaces itself.
• Shared decoding. Players showing the same animation decode it once and share the bitmaps.
• Smooth. Large files decode off the UI thread, and the canvas repaints only when the frame changes.
• Light. The SVGA format is read by the package itself; no protobuf runtime.

Install

dependencies:
  flutter_svga_easyplayer: ^0.1.0

import 'package:flutter_svga_easyplayer/flutter_svga_easyplayer.dart';

Animations with sound use audioplayers; follow its platform setup if you need sound.

Usage

// From the network
const SVGAEasyPlayer(resUrl: 'https://cdn.example.com/gift.svga')

// From an asset
const SVGAEasyPlayer(assetsName: 'assets/gift.svga')

A fuller example:

SVGAEasyPlayer(
  resUrl: url,
  loops: 0, // play once
  fit: BoxFit.cover,
  volume: 0.5,
  placeholder: const CircularProgressIndicator(),
  errorBuilder: (context, error) => const Icon(Icons.broken_image),
  onFinished: () => Navigator.pop(context),
)

Option	Default	What it does
resUrl / assetsName	—	Where the animation comes from.
loops	null	null repeats forever, 0 plays once, n plays n + 1 times.
onFinished	—	Called when a finite playback ends.
fit	BoxFit.contain	How the animation fills its box.
volume / isMute	1.0 / false	Sound level, and mute without losing it.
placeholder	nothing	Shown while loading.
errorBuilder / onError	nothing	Shown, or called, when loading fails.
onLoaded	—	Called with the decoded animation before it plays.
clearsAfterStop	true	Blank the canvas when playback ends; false keeps the last frame.
useCache	true	false loads fresh and stores nothing, for this widget only.
clearCacheOnDispose	false	Delete the cached file when the widget is removed.
headers / timeout	— / 30 s	For the download.

Errors

Every failure extends SVGAException and carries message, source and cause.

Type	When
SVGANetworkException	The request failed or the server answered with a non-2xx statusCode.
SVGATimeoutException	The download took longer than timeout.
SVGAFormatException	Not a complete SVGA 2.x file: an error page, a cut-off download, an SVGA 1.x archive.
SVGAAssetException	The asset is not in the bundle.

errorBuilder: (context, error) => switch (error) {
  SVGANetworkException(statusCode: 404) => const Text('Not found'),
  SVGATimeoutException() => const Text('Slow connection'),
  _ => const Icon(Icons.broken_image),
},

Caching

Both caches work without configuration.

// Downloaded files, on disk
SVGACache.shared
  ..setMaxCacheSize(200 * 1024 * 1024)   // default 100 MB
  ..setMaxAge(const Duration(days: 30)); // default 7 days
await SVGACache.shared.clear();

// Decoded animations, in memory
SVGAMemoryCache.shared.maxIdleBytes = 64 * 1024 * 1024; // default 32 MB
SVGAMemoryCache.shared.clear();

Over the disk limit, the least recently used files are removed first. Assets are read from the app bundle and are not copied to disk.

Precaching

Download animations ahead of time so the first playback starts instantly.

final result = await SVGAPrecacheManager.shared.precache(
  ['https://cdn.example.com/a.svga', 'https://cdn.example.com/b.svga'],
  delay: const Duration(seconds: 2),
  onProgress: (done, total, url, ok) {},
);

SVGAPrecacheManager.shared.cancel();

It never throws, skips files that are already cached, and stores a download only after verifying it. Calling it on every launch is safe.

Full control

SVGAAnimationController is a regular AnimationController.

final controller = SVGAAnimationController(vsync: this);

final movie = await SVGAParser.shared.decodeFromURL(url); // or decodeFromAssets
controller
  ..videoItem = movie
  ..repeat();

// in build:
SVGAImage(controller)

Replace parts of an animation at runtime by layer name:

movie.dynamicItem
  ..setText(textPainter, 'banner')
  ..setHidden(true, 'watermark')
  ..setDynamicDrawer((canvas, frame) {}, 'badge');
await movie.dynamicItem.setImageWithUrl(avatarUrl, 'avatar');

Players that share a cached animation also share its dynamicItem; pass useCache: false to SVGAEasyPlayer when one widget needs its own.

Performance

Compared with 0.0.7 on the gift animations in the example app, using test/benchmark/render_bench.dart. Output was compared pixel for pixel on 173 frames from 15 files and is identical.

Animation	Decode	Paint one frame
kiss (54 KB, 10 layers)	0.8 → 0.6 ms	40 → 33 µs
corgi-cloud (118 KB, 39 layers)	2.2 → 1.5 ms	64 → 52 µs
bunny-birthday-cake (240 KB, 100 layers)	5.7 → 3.8 ms	97 → 68 µs
blue-rose-heart (132 KB, 102 layers)	13.5 → 2.7 ms	136 → 112 µs
heart-jar (165 KB, 609 layers)	18.3 → 3.7 ms	283 → 51 µs

Measured in the Flutter test environment on one machine, so read them as relative numbers.

Platforms

Android, iOS, macOS, Windows and Linux. Web is experimental: no disk cache, and decoding runs on the main thread.

SVGA 2.x files are supported. Matte layers are not rendered.

Migrating from 0.0.x

Widget code keeps working. Three things changed:

• MovieEntity is a plain Dart class, not a protobuf message. params, sprites, audios, dynamicItem, autorelease and dispose() are the same.
• Load failures are SVGAExceptions instead of raw HTTP or zlib errors.
• Assets are no longer copied into the disk cache, so precacheAssets only checks that they exist.

License

MIT