159 lines
4.0 KiB
Dart
159 lines
4.0 KiB
Dart
import 'dart:async';
|
||
import 'dart:typed_data';
|
||
import 'package:camera/camera.dart';
|
||
import 'package:flutter/foundation.dart';
|
||
import 'package:image/image.dart' as img;
|
||
import '../utils/app_config.dart';
|
||
|
||
class CameraService extends ChangeNotifier {
|
||
CameraController? _controller;
|
||
List<CameraDescription> _cameras = [];
|
||
bool _isInitialized = false;
|
||
bool _isStreaming = false;
|
||
Timer? _captureTimer;
|
||
|
||
CameraController? get controller => _controller;
|
||
bool get isInitialized => _isInitialized;
|
||
bool get isStreaming => _isStreaming;
|
||
|
||
/// 初始化相机
|
||
Future<void> initialize() async {
|
||
try {
|
||
_cameras = await availableCameras();
|
||
if (_cameras.isEmpty) {
|
||
print('没有可用的相机');
|
||
return;
|
||
}
|
||
|
||
// 使用后置摄像头
|
||
final camera = _cameras.firstWhere(
|
||
(camera) => camera.lensDirection == CameraLensDirection.back,
|
||
orElse: () => _cameras.first,
|
||
);
|
||
|
||
_controller = CameraController(
|
||
camera,
|
||
ResolutionPreset.medium, // 中等分辨率，平衡质量和性能
|
||
enableAudio: false,
|
||
imageFormatGroup: ImageFormatGroup.jpeg,
|
||
);
|
||
|
||
await _controller!.initialize();
|
||
_isInitialized = true;
|
||
notifyListeners();
|
||
|
||
print('相机初始化成功');
|
||
} catch (e) {
|
||
print('相机初始化失败: $e');
|
||
_isInitialized = false;
|
||
}
|
||
}
|
||
|
||
/// 拍摄单张照片
|
||
Future<Uint8List?> takePicture() async {
|
||
if (!_isInitialized || _controller == null) return null;
|
||
|
||
try {
|
||
final XFile image = await _controller!.takePicture();
|
||
final bytes = await image.readAsBytes();
|
||
|
||
// 压缩图像
|
||
final compressedBytes = await _compressImage(bytes);
|
||
return compressedBytes;
|
||
} catch (e) {
|
||
print('拍照失败: $e');
|
||
return null;
|
||
}
|
||
}
|
||
|
||
/// 开始实时捕获（定时拍照）
|
||
void startStreaming(Function(Uint8List) onImageCaptured) {
|
||
if (_isStreaming) return;
|
||
|
||
_isStreaming = true;
|
||
notifyListeners();
|
||
|
||
_captureTimer = Timer.periodic(AppConfig.captureInterval, (timer) async {
|
||
if (!_isStreaming) {
|
||
timer.cancel();
|
||
return;
|
||
}
|
||
|
||
final imageBytes = await takePicture();
|
||
if (imageBytes != null) {
|
||
onImageCaptured(imageBytes);
|
||
}
|
||
});
|
||
|
||
print('开始实时捕获，间隔: ${AppConfig.captureInterval.inMilliseconds}ms');
|
||
}
|
||
|
||
/// 停止实时捕获
|
||
void stopStreaming() {
|
||
_isStreaming = false;
|
||
_captureTimer?.cancel();
|
||
_captureTimer = null;
|
||
notifyListeners();
|
||
print('停止实时捕获');
|
||
}
|
||
|
||
/// 压缩图像
|
||
Future<Uint8List> _compressImage(Uint8List bytes) async {
|
||
return await compute(_compressImageIsolate, bytes);
|
||
}
|
||
|
||
/// 在独立 Isolate 中压缩图像（避免阻塞 UI）
|
||
static Uint8List _compressImageIsolate(Uint8List bytes) {
|
||
// 解码图像
|
||
img.Image? image = img.decodeImage(bytes);
|
||
if (image == null) return bytes;
|
||
|
||
// 调整大小
|
||
if (image.width > AppConfig.imageMaxWidth ||
|
||
image.height > AppConfig.imageMaxHeight) {
|
||
image = img.copyResize(
|
||
image,
|
||
width: AppConfig.imageMaxWidth,
|
||
height: AppConfig.imageMaxHeight,
|
||
);
|
||
}
|
||
|
||
// 压缩为 JPEG
|
||
final compressed = img.encodeJpg(image, quality: AppConfig.imageQuality);
|
||
|
||
print('图像压缩: ${bytes.length} bytes -> ${compressed.length} bytes');
|
||
return Uint8List.fromList(compressed);
|
||
}
|
||
|
||
/// 切换摄像头
|
||
Future<void> switchCamera() async {
|
||
if (_cameras.length < 2) return;
|
||
|
||
final currentLens = _controller?.description.lensDirection;
|
||
final newCamera = _cameras.firstWhere(
|
||
(camera) => camera.lensDirection != currentLens,
|
||
orElse: () => _cameras.first,
|
||
);
|
||
|
||
await _controller?.dispose();
|
||
|
||
_controller = CameraController(
|
||
newCamera,
|
||
ResolutionPreset.medium,
|
||
enableAudio: false,
|
||
imageFormatGroup: ImageFormatGroup.jpeg,
|
||
);
|
||
|
||
await _controller!.initialize();
|
||
notifyListeners();
|
||
}
|
||
|
||
/// 释放资源
|
||
@override
|
||
void dispose() {
|
||
stopStreaming();
|
||
_controller?.dispose();
|
||
super.dispose();
|
||
}
|
||
}
|