使用cordova调用相机在相机中添加蒙版

变态的需求，要在cordova调起得相机上加入一拍照的轮廓，在cordova的插件中拿不到拍照的方法，起初选用UIImagePickerController的cameraOverlayView属行，结果拍照界面有轮廓，拍照完轮廓消失不了，纠结了，然后就想各种方法去获取拍照的方法的调用，最终也没成功😭，然后转换思想，通过查看相机的debug view Hierarchy 发现如果能获取到CAMPreviewView，把轮廓图加到这上面就可以解决问题，然后就用方法：

- (UIView *)findSubView:(UIView *)aView withName:(NSString *)name{
    NSString *desc = NSStringFromClass(aView.class);
    if ([name isEqualToString:desc]) {
        return aView;
    }
    for (UIView *v  in aView.subviews) {
        UIView *resultView = [self findSubView:v withName:name];
        if (resultView) {
            return resultView;
        }
    }
    return nil;
}

查询CAMPreviewView，然后在

[weakSelf.viewController presentViewController:cameraPicker animated:YES completion:^{
                    UIView * preview = [weakSelf findSubView:cameraPicker.view withName:@"CAMPreviewView"];
                    YTLog(@"%f",preview.frame.size.width/preview.frame.size.height);
                    UIImageView *imageView = [[UIImageView alloc] init];
                    imageView.frame = CGRectMake(0, 0, preview.bounds.size.width, preview.bounds.size.height);
                    imageView.image = [UIImage imageNamed:@"sfz1.png"];

                    [preview addSubview:imageView];
                    
                    
                    weakSelf.hasPendingOperation = NO;
                    
                }];

中加入图片，解决问题，收工！