multi_vid_player/lib/pages/canvas_player/widgets/canvas_player.dart

import 'dart:typed_data';
import 'package:fis_measure/view/player/controller.dart';
import 'package:fis_measure/view/player/enums.dart';
import 'package:fis_measure/view/player/events.dart';
import 'package:flutter/material.dart';
import 'dart:ui' as ui;
import 'vid_painter.dart';

///基于Canvas组件的播放器
class VidCanvasPlayer extends StatefulWidget {
  const VidCanvasPlayer(
    this.controller, {
    Key? key,
    this.width,
    this.height,
  }) : super(key: key);

  final VidPlayerController controller;

  final double? width;
  final double? height;

  @override
  State<StatefulWidget> createState() => _VidCanvasPlayerState();
}

class _VidCanvasPlayerState extends State<VidCanvasPlayer> {
  Uint8List? frameBytes;
  ui.Image? image;
  @override
  void initState() {
    widget.controller.eventHandler.addListener(onControllerEvent);
    super.initState();
  }

  @override
  void didUpdateWidget(covariant VidCanvasPlayer oldWidget) {
    if (oldWidget.controller != widget.controller) {
      throw UnsupportedError("[VidTestPlayer] unsupport replace controller.");
    }
    super.didUpdateWidget(oldWidget);
  }

  void onControllerEvent(Object sender, VidPlayerEvent e) {
    if (e is VidPlayerStatusChangeEvent) {
      if (!widget.controller.hasView) {
        setState(() {});
      }
    }
    if (e is VidPlayerFrameIndexChangeEvent) {
      onFrameChanged(e);
    }
    if (e is VidPlayerBrightnessChangeEvent) {
      updateFrame();
    }
    if (e is VidPlayerContrastChangeEvent) {
      updateFrame();
    }
  }

  void onFrameChanged(VidPlayerFrameIndexChangeEvent e) {
    loadFrame(e.bytes);
  }

  void loadFrame(Uint8List bytes) async {
    image = await decodeImageFromList(bytes);
    setState(() {});
  }

  void updateFrame() {
    setState(() {});
  }

  @override
  Widget build(BuildContext context) {
    Widget? child;
    switch (widget.controller.status) {
      case VidPlayStatus.init:
        child = Container(child: const Text("Loading"));
        break;
      case VidPlayStatus.ready:
        child = Container(child: const Text("Ready"));
        break;
      case VidPlayStatus.loadFail:
        child = Container(child: const Text("Load fail"));
        break;
      case VidPlayStatus.play:
        child = buildFrameView(context);
        break;
      case VidPlayStatus.pause:
        child = Text(
          widget.controller.currentFrameIndex.toString(),
        );
        break;
      case VidPlayStatus.stop:
      case VidPlayStatus.dispose:
        child = Container(child: const Text("Closed"));
        break;
    }
    return buildBox(context, child);
  }

  Widget buildBox(BuildContext context, Widget child) {
    return Container(
      alignment: Alignment.center,
      child: child,
    );
  }

  Widget buildFrameView(BuildContext context) {
    if (image != null) {
      // final size = MediaQuery.of(context).size;
      return CustomPaint(
        painter: VidPainter(image: image),
        isComplex: false, //是否为复杂图像（true会缓存）
      );
    } else {
      return Container();
    }
  }

  @override
  void dispose() {
    widget.controller.eventHandler.removeListener(onControllerEvent);
    super.dispose();
  }
}