iPhone：相机预览叠加

Question

如何将叠加层 (UIImageView) 添加到相机预览并 处理这个问题吗？

我之前尝试执行此操作（例如使用 UIImagePickerController 并将图像添加为子视图）失败了。

Answer 1

对于您的实现文件：

- (IBAction)TakePicture:(id)sender {

    // Create image picker controller
    UIImagePickerController *imagePicker = [[UIImagePickerController alloc] init];

    // Set source to the camera
    imagePicker.sourceType =  UIImagePickerControllerSourceTypeCamera;

        // Delegate is self
        imagePicker.delegate = self;

        OverlayView *overlay = [[OverlayView alloc] initWithFrame:CGRectMake(0, 0, 320, 480)];     

        // Insert the overlay:
        imagePicker.cameraOverlayView = overlay;

       // Allow editing of image ?
        imagePicker.allowsImageEditing = YES;
        [imagePicker setCameraDevice:
        UIImagePickerControllerCameraDeviceFront];
        [imagePicker setAllowsEditing:YES];
        imagePicker.showsCameraControls=YES;
        imagePicker.navigationBarHidden=YES;
        imagePicker.toolbarHidden=YES;
        imagePicker.wantsFullScreenLayout=YES;

        self.library = [[ALAssetsLibrary alloc] init];

        // Show image picker
        [self presentModalViewController:imagePicker animated:YES];
    }

创建一个 UIView 类并添加此代码

    - (id)initWithFrame:(CGRect)frame
    {
        self = [super initWithFrame:frame];
        if (self) {
            // Initialization code


            // Clear the background of the overlay:
            self.opaque = NO;
            self.backgroundColor = [UIColor clearColor];

            // Load the image to show in the overlay:
            UIImage *overlayGraphic = [UIImage imageNamed:@"overlaygraphic.png"];
            UIImageView *overlayGraphicView = [[UIImageView alloc] initWithImage:overlayGraphic];
            overlayGraphicView.frame = CGRectMake(30, 100, 260, 200);
            [self addSubview:overlayGraphicView];

        }
        return self;
    }

Answer 2

您可以直接将 UIImageView 添加为主窗口的子视图，而不是 UIImagePicker，这样效果可能会更好。 只需确保按正确的顺序添加它们，或者

[window bringSubviewToFront:imageView];

在相机启动后致电即可。

如果您想处理 UIImageView 上的触摸，只需将 UIImageView 添加为具有透明背景的普通全屏 View 的子视图，然后将 that 添加到窗口，并使用可用于处理触摸事件的普通 UIViewController 子类。

Answer 3

查看相机叠加视图（3.1 及更高版本中提供）

@property(nonatomic, retain) UIView *cameraOverlayView