PHAuthorizationStatusLimited 选择更多照片

1.如果不想每次都弹出系统的弹窗，需要在info.plist中添加Prevent limited photos access alert 为YES

2.自己控制选择添加更多 ：

[[PHPhotoLibrary sharedPhotoLibrary] presentLimitedLibraryPickerFromViewController:self
        completionHandler:^(NSArray<NSString *> *newlySelectedAssetIdentifiers) {
     [weakSelf loadAllAssets];  // 刷新数据
}];

3.在Link Binary With Libraries 中添加PhotosUI.framework ，否则程序会闪退

4.旋转照片

- (UIImage *)rotateImageByChangingOrientation:(UIImage *)image {
  if (!image) return nil;

    UIImageOrientation currentOrientation = image.imageOrientation;
    UIImageOrientation newOrientation;

  switch (currentOrientation) {
    case UIImageOrientationUp:
        newOrientation = UIImageOrientationRight;
        break;
    case UIImageOrientationRight:
        newOrientation = UIImageOrientationDown;
        break;
    case UIImageOrientationDown:
        newOrientation = UIImageOrientationLeft;
        break;
    case UIImageOrientationLeft:
        newOrientation = UIImageOrientationUp;
        break;
    default:
        newOrientation = UIImageOrientationUp;
        break;
 }

  return [UIImage imageWithCGImage:image.CGImage
                          scale:image.scale
                    orientation:newOrientation];
}

5.调用旋转照片

self.capturedImage = [self rotateImageByChangingOrientation:self.capturedImage];

6.压缩照片

- (UIImage *)compressImage:(UIImage *)image toMaxSize:(NSInteger)maxSize {
CGFloat compression = 1.0;
NSData *imageData = UIImageJPEGRepresentation(image, compression);
NSLog(@"原图%.2fMB",(float)(imageData.length/1024.0/1024));
if (!imageData) return image;

if (imageData.length <= maxSize) {
    return image;
}

CGFloat min = 0.0;
CGFloat max = 1.0;
for (int i = 0; i < 8; i++) {
    compression = (min + max) / 2;
    imageData = UIImageJPEGRepresentation(image, compression);
    if (imageData.length < maxSize) {
        min = compression;
    } else {
        max = compression;
    }
}

imageData = UIImageJPEGRepresentation(image, min);
NSLog(@"压缩后图片%.2fMB",(float)(imageData.length/1024.0/1024));
return [[UIImage alloc] initWithData:imageData];
}

7.调用

UIImage *image = [self compressImage:self.resultImageView.image toMaxSize:1.8 * 1024 * 1024];

8. 拍照

   - (void)setupCamera {
      self.session = [[AVCaptureSession alloc] init];
      self.session.sessionPreset = AVCaptureSessionPresetPhoto;
   
      AVCaptureDevice *backCamera = [AVCaptureDevice defaultDeviceWithDeviceType:AVCaptureDeviceTypeBuiltInWideAngleCamera mediaType:AVMediaTypeVideo position:AVCaptureDevicePositionBack];
   
   // 开启连续自动对焦，防抖防糊
    if ([backCamera isFocusModeSupported:AVCaptureFocusModeContinuousAutoFocus]) {
        [backCamera lockForConfiguration:nil];
        backCamera.focusMode = AVCaptureFocusModeContinuousAutoFocus;
        [backCamera unlockForConfiguration];
    }
   
     NSError *error;
    AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:backCamera error:&error];
    if ([self.session canAddInput:input]) {
       [self.session addInput:input];
    }
   
    self.photoOutput = [[AVCapturePhotoOutput alloc] init];
    if ([self.session canAddOutput:self.photoOutput]) {
         [self.session addOutput:self.photoOutput];
      }
   
     self.previewLayer = [AVCaptureVideoPreviewLayer layerWithSession:self.session];
     self.previewLayer.frame = self.view.bounds;
     self.previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
     [self.view.layer addSublayer:self.previewLayer];
   }
   
    - (void)startSession {
      if (_session && !_session.isRunning) {
          dispatch_async(dispatch_get_global_queue(0, 0), ^{
             [self.session startRunning];
             self.isSessionRunning = YES;
       });
       }
    }
   
   - (void)stopSession {
      if (_session && _session.isRunning) {
        dispatch_async(dispatch_get_global_queue(0, 0), ^{
          [self.session stopRunning];
          self.isSessionRunning = NO;
       });
     }
   }
   

9. 拍照处理

   - (void)captureAction {
       if (!self.isSessionRunning) return;
       AVCapturePhotoSettings *settings = [AVCapturePhotoSettings photoSettings];
       [self.photoOutput capturePhotoWithSettings:settings delegate:self];
   }
   
     - (void)captureOutput:(AVCapturePhotoOutput *)output didFinishProcessingPhoto:(AVCapturePhoto *)photo error:(NSError *)error {
         if (error || !photo) return;
   
          __weak typeof(self) weakSelf = self;
         dispatch_async(dispatch_get_global_queue(0, 0), ^{
               NSData *data = photo.fileDataRepresentation;
               UIImage *image = [UIImage imageWithData:data];
       
                dispatch_async(dispatch_get_main_queue(), ^{
                  self.rotateAngle = 0;
                  weakSelf.capturedImage = image;
                  weakSelf.resultImageView.image = image;
                  weakSelf.resultView.hidden = NO;
                  weakSelf.guideContainer.hidden = YES;
              });
          });
    }