93 lines
2.1 KiB
Dart
93 lines
2.1 KiB
Dart
import 'dart:async';
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import 'package:flutter/material.dart';
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import 'dart:ui' as ui;
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import 'package:flutter/services.dart';
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class SpeedControlledGif extends StatefulWidget {
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final String assetPath;
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final double speedFactor;
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final BoxFit? fit;
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/// [speedFactor] 播放速度倍数，默认1.0，
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/// 大于1表示加速播放，小于1表示减速播放
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const SpeedControlledGif(
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this.assetPath, {
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Key? key,
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this.speedFactor = 1.0,
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this.fit,
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}) : super(key: key);
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@override
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_SpeedControlledGifState createState() => _SpeedControlledGifState();
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}
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class _SpeedControlledGifState extends State<SpeedControlledGif> {
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ui.Codec? _codec;
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ui.FrameInfo? _currentFrame;
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Timer? _timer;
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bool _isDisposed = false;
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@override
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void initState() {
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super.initState();
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_loadGif();
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}
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Future<void> _loadGif() async {
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final data = await rootBundle.load(widget.assetPath);
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_codec = await ui.instantiateImageCodec(data.buffer.asUint8List());
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if (_isDisposed) return;
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_showNextFrame();
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}
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Future<void> _showNextFrame() async {
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if (_isDisposed || _codec == null) return;
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_currentFrame = await _codec!.getNextFrame();
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if (_isDisposed) return;
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if (mounted) {
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setState(() {});
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}
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// 取当前帧持续时间，单位毫秒
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final baseDuration = _currentFrame?.duration.inMilliseconds ?? 100;
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// 限制最小帧间隔，防止刷新过快
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const minFrameDuration = 50;
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// 计算实际播放帧间隔，speedFactor越大速度越快
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final adjustedDuration = (baseDuration / widget.speedFactor)
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.round()
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.clamp(minFrameDuration, 10000);
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_timer = Timer(Duration(milliseconds: adjustedDuration), _showNextFrame);
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}
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@override
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void dispose() {
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_isDisposed = true;
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_timer?.cancel();
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_codec?.dispose();
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super.dispose();
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}
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@override
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Widget build(BuildContext context) {
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if (_currentFrame == null) {
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// 加载中或无帧时显示空容器或占位
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return Container();
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}
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return RawImage(
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image: _currentFrame!.image,
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fit: widget.fit,
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);
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}
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}
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