Capture overlayimage using AVFoundation framework - iphone

Question

I want to take picture with overlay image.
code:
- (void)addStillImageOutput
{
// NSLog(#"You capture image");
[self setStillImageOutput:[[[AVCaptureStillImageOutput alloc] init] autorelease]];
NSDictionary *outputSettings = [[NSDictionary alloc] initWithObjectsAndKeys:AVVideoCodecJPEG,AVVideoCodecKey,nil];
[[self stillImageOutput] setOutputSettings:outputSettings];
AVCaptureConnection *videoConnection = nil;
for (AVCaptureConnection *connection in [[self stillImageOutput] connections]) {
for (AVCaptureInputPort *port in [connection inputPorts]) {
if ([[port mediaType] isEqual:AVMediaTypeVideo] ) {
videoConnection = connection;
break;
}
}
if (videoConnection) {
break;
}
}
[[self captureSession] addOutput:[self stillImageOutput]];
}
- (void)captureStillImage
{
AVCaptureConnection *videoConnection = nil;
for (AVCaptureConnection *connection in [[self stillImageOutput] connections]) {
for (AVCaptureInputPort *port in [connection inputPorts]) {
if ([[port mediaType] isEqual:AVMediaTypeVideo]) {
videoConnection = connection;
break;
}
}
if (videoConnection) {
break;
}
}
NSLog(#"about to request a capture from: %#", [self stillImageOutput]);
[[self stillImageOutput] captureStillImageAsynchronouslyFromConnection:videoConnection
completionHandler:^(CMSampleBufferRef imageSampleBuffer, NSError *error) {
CFDictionaryRef exifAttachments = CMGetAttachment(imageSampleBuffer, kCGImagePropertyExifDictionary, NULL);
if (exifAttachments) {
NSLog(#"attachements: %#", exifAttachments);
} else {
NSLog(#"no attachments");
}
NSData *imageData = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageSampleBuffer];
UIImage *image = [[UIImage alloc] initWithData:imageData];
[self setStillImage:image];
[image release];
[[NSNotificationCenter defaultCenter] postNotificationName:kImageCapturedSuccessfully object:nil];
}];
}
OverlayImage:
-(void)ButtonPressed1{
UIImageView *overlayImageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"sof.png"]];
[overlayImageView setFrame:CGRectMake(30, 100, 260, 200)];
[[self view] addSubview:overlayImageView];
[overlayImageView release];
}

Answer 1

captureStillImageAsynchronouslyFromConnection captures only data from connection (AVCaptureConnection) and the additional images are not in connection. They are in the view.
So, to "generate" an image with all elements (picture and overlay), you must have to do something like this:
UIGraphicsBeginImageContext(stillImage.size);
[stillImage drawInRect:CGRectMake(0, 0, picture.size.width, picture.size.height)];
[overlayImageView drawInRect:CGRectMake(overlayImageView.frame.origin.x, overlayImageView.frame.origin.y, overlayImageView.frame.size.width, overlayImageView.frame.size.height)];
UIImage *result = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
This code is considering that picture size is equal to screen size. If picture size is different, you have to calculate the coordinates to place the overlay in the drawRect method. Sorry for bad english.