How to get the custom overlay for UIImagePicker ca

问题:

I am interested in using a custom overlay for the UIImagePickerController for camera controls that take the entire screen, very similar to what the default Camera app does when switched to the video function.

I have referenced several questions here on SO on this topic, particularly this one, as well as the Apple example on how to use a custom overlay for the UIImagePickerController, but none of them have been able to produce a successful, full-screen result with iOS 7.

So far, this is what the camera UI looks like with the custom overlay (without any buttons):

Note that there is a black bar in the bottom of the screen. I noticed that I could get the black bar removed if I change the cameraAspectRatio to 1, but this distorts the camera zoom as it then has a very zoomed in view. Is there a way to have full screen without either distorting the zoom too much (I understand that a small bit is necessary), and also remove the black bar?

Here is my code that configures the custom overlay:

{
        self.imagePickerController.showsCameraControls = NO;

        [[NSBundle mainBundle] loadNibNamed:@"overlayView" owner:self options:nil];
        self.overlayView.frame = self.imagePickerController.cameraOverlayView.frame;
        self.imagePickerController.cameraOverlayView = self.overlayView;
        self.overlayView = nil;

        // Device's screen size (ignoring rotation intentionally):
        CGSize screenSize = [[UIScreen mainScreen] bounds].size;


        float cameraAspectRatio = 4.0 / 3.0; //! Note: 4.0 and 4.0 works
        float imageWidth = floorf(screenSize.width * cameraAspectRatio);
        float scale = ceilf((screenSize.height / imageWidth) * 10.0) / 10.0;

        self.imagePickerController.cameraViewTransform = CGAffineTransformMakeScale(scale, scale);

    }

Update:

An additional issue that I noticed is, the picture that is shown in camera preview is always smaller and has less details than the picture that is saved when the method [self.imagePickerController takePicture]. To illustrate:

This is what the keyboard looks like in the camera preview with the black bar below (sorry its a bit shaky):

However, note that the actual captured image in the preview panel has a lot more details as shown here, especially towards the top, as well as both left and right.

My question is, how would be able to set my camera preview so that what the user sees in preview is exactly the image that it will capture and could be shown to them afterwards? Thanks!

Update 2

Here is the entire code in viewDidLoad that sets up the camera controls.

- (void)viewDidLoad
{
    [super viewDidLoad];

    //Appearance configuration
    self.navigationItem.hidesBackButton = YES;

    //UIImagePickerController initialization and setup
    self.imagePickerController = [[UIImagePickerController alloc] init];
    self.imagePickerController.delegate = self;
    self.imagePickerController.allowsEditing = NO;
    if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]){
        self.imagePickerController.sourceType = UIImagePickerControllerSourceTypeCamera; //if there is a camera avaliable
    } else {
        self.imagePickerController.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;//otherwise go to the folder
    }
    self.imagePickerController.mediaTypes = [[NSArray alloc] initWithObjects: (NSString *) kUTTypeImage, nil];
    if (self.imagePickerController.sourceType == UIImagePickerControllerSourceTypeCamera)
    {
        self.imagePickerController.showsCameraControls = NO;

        [[NSBundle mainBundle] loadNibNamed:@"overlayView" owner:self options:nil];
        self.overlayView.frame = self.imagePickerController.cameraOverlayView.frame;
        self.imagePickerController.cameraOverlayView = self.overlayView;
        self.overlayView = nil;

        // Device's screen size (ignoring rotation intentionally):
        CGSize screenSize = [[UIScreen mainScreen] bounds].size;

        int heightOffset = 0;

        if(SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(@"7.0"))
        {
            heightOffset = 120; //whole screen :)
        }

        float cameraAspectRatio = 4.0 / 3.0; //! Note: 4.0 and 4.0 works
        float imageWidth = floorf(screenSize.width * cameraAspectRatio);
        float scale = ceilf(((screenSize.height + heightOffset) / imageWidth) * 10.0) / 10.0;

        self.imagePickerController.cameraViewTransform = CGAffineTransformMakeScale(scale, scale);

    }
}

And in viewWillAppear, I call the image picker view:

BOOL modalPresent = (BOOL)(self.presentedViewController);
    //Present the Camera UIImagePicker if no image is taken
    if (!appDelegate.imageStorageDictionary[@"picture1"]){
        if (modalPresent == NO){ //checks if the UIImagePickerController is modally active
            [self presentViewController:self.imagePickerController animated:NO completion:nil];
        }
    }

回答1:

After many attempts, this is what worked for me with many thanks to other people's suggestions. The following facts were very helpful to know and keep in mind:

The camera's points resolution is 426 * 320. In order for the camera preview's height to be stretched to the phone's screen height of 568, it needs to be multiplied by a factor of 1.3333 when using CGAffineTransformScale.

Note that the below are hard coded with various numbers based on the iPhone 5's screen resolution in points. They could be improved by using such objects such as screen.height, screen.width and other variables to make it applicable to iPhone 4/4s dimensions as well.

    self.imagePickerController.showsCameraControls = NO;

    [[NSBundle mainBundle] loadNibNamed:@"overlayView" owner:self options:nil];
    self.overlayView.frame = self.imagePickerController.cameraOverlayView.frame;
    self.imagePickerController.cameraOverlayView = self.overlayView;
    self.overlayView = nil;

    //For iphone 5+
    //Camera is 426 * 320. Screen height is 568.  Multiply by 1.333 in 5 inch to fill vertical
    CGAffineTransform translate = CGAffineTransformMakeTranslation(0.0, 71.0); //This slots the preview exactly in the middle of the screen by moving it down 71 points
    self.imagePickerController.cameraViewTransform = translate;

    CGAffineTransform scale = CGAffineTransformScale(translate, 1.333333, 1.333333);
    self.imagePickerController.cameraViewTransform = scale;

回答2:

In Swift

var picker: UIImagePickerController = UIImagePickerController();

picker.sourceType = UIImagePickerControllerSourceType.Camera;

picker.showsCameraControls = false;

var screenBounds: CGSize = UIScreen.mainScreen().bounds.size;

var scale = screenBounds.height / screenBounds.width;

picker.cameraViewTransform = CGAffineTransformScale(picker.cameraViewTransform, scale, scale);

回答3:

Make sure that you account for 20px status bar change in iOS7. If you are facing a 20px black screen at bottom of the screen then this will be your issue. You can check that whether the app is running in ios7 or not by one of these preprocessors

#define SYSTEM_VERSION_EQUAL_TO(v)                  ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] == NSOrderedSame)
#define SYSTEM_VERSION_GREATER_THAN(v)              ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] == NSOrderedDescending)
#define SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(v)  ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] != NSOrderedAscending)
#define SYSTEM_VERSION_LESS_THAN(v)                 ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] == NSOrderedAscending)
#define SYSTEM_VERSION_LESS_THAN_OR_EQUAL_TO(v)     ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] != NSOrderedDescending)

And you can make following changes to your code and see if it works

{
        self.imagePickerController.showsCameraControls = NO;

        [[NSBundle mainBundle] loadNibNamed:@"overlayView" owner:self options:nil];
        self.overlayView.frame = self.imagePickerController.cameraOverlayView.frame;
        self.imagePickerController.cameraOverlayView = self.overlayView;
        self.overlayView = nil;

        // Device's screen size (ignoring rotation intentionally):
        CGSize screenSize = [[UIScreen mainScreen] bounds].size;

        int heightOffset = 0;

        if(SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(@"7.0"))
        {
            heightOffset = 20;
        }

        float cameraAspectRatio = 4.0 / 3.0; //! Note: 4.0 and 4.0 works
        float imageWidth = floorf(screenSize.width * cameraAspectRatio);
        float scale = ceilf(((screenSize.height + heightOffset) / imageWidth) * 10.0) / 10.0;

        self.imagePickerController.cameraViewTransform = CGAffineTransformMakeScale(scale, scale);

    }

Please let me know if it works. I haven't coded it to test.

回答4:

Because the screen aspect ratio is different than the 4/3 ratio of the camera itself, you need (as you mentioned) to slightly crop the edges in order to have the image extend to the bottom.

In order to do that, you need to have the width be wide enough so that the height can be the full screen. So, your image width and height must be:

float cameraAspectRatio = 4.0 / 3.0; //! Note: 4.0 and 4.0 works
float imageWidth = screenSize.height / cameraAspectRatio;

You'll also probably want the view presenting the camera image to be that width that extends off both sides of the screen.

回答5:

There is a way easier method to get your overlay fullscreen at least tested in iOS 9.

let view    = ... your overlayView
let bounds  = UIScreen.mainScreen().bounds
view.center = CGPoint(x: bounds.midX, y: bounds.midY)
view.bounds = bounds
self.imagePicker.cameraOverlayView = view

回答6:

I don't know why you use screen size. Just try this simple code:

if ([UIImagePickerController isSourceTypeAvailable: UIImagePickerControllerSourceTypeCamera])

{

     UIImagePickerController *controller = [[UIImagePickerController alloc] init];
     controller.sourceType = UIImagePickerControllerSourceTypeCamera;
     controller.allowsEditing = NO;
     controller.mediaTypes = [UIImagePickerController availableMediaTypesForSourceType:
     UIImagePickerControllerSourceTypeCamera];
     controller.delegate = self;
     [self presentViewController:controller animated:NO completion:^{}];
}

回答7:

Try this code to maintain your resultant image in custom size. I got result by using custom method for getting resultant image as custom size.

First create IBOutlet for UIImageview.

-(void)imagePickerController:(UIImagePickerController *)picker
didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    NSString *mediaType = info[UIImagePickerControllerMediaType];
[self dismissViewControllerAnimated:YES completion:nil];


if ([mediaType isEqualToString:(NSString *)kUTTypeImage]) {
    OriginalImage=info[UIImagePickerControllerOriginalImage];
    image = info[UIImagePickerControllerOriginalImage];
//----------------------------------------
     imageview.image = image; //------------- additional method for custom image size
     self resizeImage];


//-----------------------------------------
        if (_newMedia)
            UIImageWriteToSavedPhotosAlbum(image,self,@selector(image:finishedSavingWithError:contextInfo:),nil);

}
else if ([mediaType isEqualToString:(NSString *)kUTTypeMovie])
{
    // Code here to support video if enabled
}

}

//---- Resize the original image by using custom method----------------------

-(void)resizeImage
{
    UIImage *resizeImage = imageview.image;

    float width = 320;
    float height = 320;

    CGSize newSize = CGSizeMake(320,320);
    UIGraphicsBeginImageContextWithOptions(newSize,NO,0.0);
    CGRect rect = CGRectMake(0, 0, width, height);

    float widthRatio = resizeImage.size.width / width;
    float heightRatio = resizeImage.size.height / height;
    float divisor = widthRatio > heightRatio ? widthRatio : heightRatio;

    width = resizeImage.size.width / divisor;
    height = resizeImage.size.height / divisor;

    rect.size.width  = width;
    rect.size.height = height;

    //indent in case of width or height difference
    float offset = (width - height) / 2;
    if (offset > 0) {
        rect.origin.y = offset;
    }
    else {
        rect.origin.x = -offset;
    }

    [resizeImage drawInRect: rect];

    UIImage *smallImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

imageview.image = smallImage;
imageview.contentMode = UIViewContentModeScaleAspectFit;

}

回答8:

To solve a similar problem, I instantiated a ViewController from storyboard and used the controller's view as camera overlay. I don't know if it's what you're looking for, but i used the following code:

UIImagePickerController *globalPicker = [[UIImagePickerController alloc] init];
globalPicker.delegate = self;
globalPicker.sourceType = UIImagePickerControllerSourceTypeCamera;controller=[self.storyboard instantiateViewControllerWithIdentifier:@"myVC"];
overlayView = controller.view;
UIView *cameraView=[[UIView alloc] initWithFrame:self.view.bounds];
[cameraView addSubview:overlayView];
[globalPicker setCameraOverlayView:cameraView];

回答9:

Try this code, it works fine for me

UIImagePickerController *cameraUI = [[UIImagePickerController alloc] init];
cameraUI.sourceType = UIImagePickerControllerSourceTypeCamera;
cameraUI.showsCameraControls = NO;

CGSize screenSize = [[UIScreen mainScreen] bounds].size;
float cameraAspectRatio = 4.0 / 3.0;
float imageHeight = floorf(screenSize.width * cameraAspectRatio);
float scale = screenSize.height / imageHeight;
float trans = (screenSize.height - imageHeight)/2;
CGAffineTransform translate = CGAffineTransformMakeTranslation(0.0, trans);
CGAffineTransform final = CGAffineTransformScale(translate, scale, scale);
cameraUI.cameraViewTransform = final
;
cameraUI.delegate = self;
[self presentViewController:cameraUI animated:YES completion:nil];

This code assumes that the aspect of the original camera preview area is 4:3.