Question

Special Thanks in advance……
I m the beggininer in iphone software development.

Just looking for how to programmatically add real time a watermark image to camera view using cocoa. Not looking for a step by step ( although that would awesome ), but more or less looking for where I should start looking to learn how. Are there frameworks developed to work for this. Would like something native to objective-C using XCode framework because I would like to eventually give this a go on the iPhone. Any help would be great.

Answer 1

UPDATE: here’s my other answer about how this overlay view can be put under the camera animations: camera overlay view – just for preview?

Helo Rajendra!

I’ve created a simple Window-based iPhone OS Application to give you a very simple example on what and how should be done to capture photos with camera, overlay views in camera mode, resize and merge images. This project is actually has only AppDelegate header and implementation files and can be easily reproduced in XCode.

Here’s the header file:

//
//  CameraWatermarkAppDelegate.h
//  CameraWatermark
//
//  Created by Ivan Karpan on 1/16/10.
//  Copyright __MyCompanyName__ 2010. All rights reserved.
//

#import <UIKit/UIKit.h>


@interface CameraWatermarkAppDelegate : NSObject < UIApplicationDelegate, UIImagePickerControllerDelegate, UINavigationControllerDelegate > {
    UIImageView *imageView;
    UIViewController *viewController;
    UIWindow *window;
}

@property (nonatomic, retain) UIImageView *imageView;
@property (nonatomic, retain) UIViewController *viewController;
@property (nonatomic, retain) IBOutlet UIWindow *window;


@end

And here’s the implementation file:

//
//  CameraWatermarkAppDelegate.m
//  CameraWatermark
//
//  Created by Ivan Karpan on 1/16/10.
//  Copyright __MyCompanyName__ 2010. All rights reserved.
//

#import "CameraWatermarkAppDelegate.h"


const float WATERMARK_ALPHA = 0.5;


@implementation CameraWatermarkAppDelegate

@synthesize imageView, viewController, window;


- (void)applicationDidFinishLaunching:(UIApplication *)application {
    self.viewController = [[UIViewController new] autorelease];
    viewController.view.backgroundColor = [UIColor blackColor];

    // An image view to save to (and therefore display) the captured image
    self.imageView = [[UIImageView new] autorelease];
    imageView.frame = viewController.view.frame;
    [viewController.view addSubview:imageView];

    [window addSubview:viewController.view];

    UIImagePickerController *anImagePickerController = [UIImagePickerController new];
    anImagePickerController.delegate = self;
    anImagePickerController.sourceType = UIImagePickerControllerSourceTypeCamera;

    {// This block of code is only needed in case you want your watermark to be displayed also during the shooting process
        UIImageView *anImageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"Watermark.png"]];
        anImageView.alpha = WATERMARK_ALPHA;
        anImageView.contentMode = UIViewContentModeTopLeft;
        anImageView.frame = viewController.view.frame;
        anImagePickerController.cameraOverlayView = anImageView;
        [anImageView release];
    }

    // From the very beginning we simply present the image picker controller
    [viewController presentModalViewController:anImagePickerController animated:NO];
    [anImagePickerController release];
}


- (void)dealloc {
    [imageView release];
    [viewController release];
    [window release];
    [super dealloc];
}

#pragma mark UIImagePickerControllerDelegate

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
    UIGraphicsBeginImageContext(CGSizeMake(320, 480));
    // This is where we resize captured image
    [(UIImage *)[info objectForKey:UIImagePickerControllerOriginalImage] drawInRect:CGRectMake(0, 0, 320, 480)];
    // And add the watermark on top of it
    [[UIImage imageNamed:@"Watermark.png"] drawAtPoint:CGPointMake(0, 0) blendMode:kCGBlendModeNormal alpha:WATERMARK_ALPHA];
    // Save the results directly to the image view property
    imageView.image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    // Dismiss the image picker controller and look at the results
    [picker dismissModalViewControllerAnimated:YES];
}


@end

I hope this will serve you as a starting point.