app-zj/lib/utils/file_utils.dart

import 'dart:io';
import 'dart:typed_data';
import 'dart:ui' as ui;

import 'package:flutter/cupertino.dart';
import 'package:flutter/rendering.dart';
import 'package:path_provider/path_provider.dart';

class FileUtils {
  static Future<File> convertUint8ListToFile(Uint8List data, String fileName) async {
    final directory = await getApplicationCacheDirectory();
    final filePath = '${directory.path}/$fileName';
    final file = File(filePath);
    await file.writeAsBytes(data);
    return file;
  }

  /// 从Context中获取图片
  static Future<Uint8List?> getBitmapFromContext(
    BuildContext? context, {
    double pixelRatio = 3.0,
  }) async {
    if (context == null) return null;
    RenderRepaintBoundary render = context.findRenderObject() as RenderRepaintBoundary;
    ui.Image image = await render.toImage(pixelRatio: pixelRatio);
    ByteData? bytes = await image.toByteData(format: ui.ImageByteFormat.png);
    return bytes?.buffer.asUint8List();
  }
}