Question

I would like to have a feature in my app that

-lets you take a picture of yourself or other that has a fame eg “Wanted:” overlaid on it.

-The user then would take the photo and the overlay and photo would be combined into one

-The resulting image usable in code.

Any ideas where to/how to start with this. Any tutorials etc.

Cheers

Answer 1

It can get a little tricky, dealing with the transform applied to the preview of the image which makes it look a little different from the one you get handed by the camera, but here is the basic idea:

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {

UIImage *img = [info objectForKey:UIImagePickerControllerOriginalImage];

// Here we are throwing away lots of image resolution -- but since our art is built for the 320 x 480 screen
// and we are worried about uploading bandwidth, crunching the image down from ~1600 x 2400 to 320 x 480 just makes sense
// note that the proportion is a little different, so the picture is slightly stretched in the y-axis, but this is augmented reality, so we like that

// note that hardwareScreenSize has to be determined by checking UIDeviceHardware

UIGraphicsBeginImageContext(hardwareScreenSize);


[img drawInRect:CGRectMake(0, ((hardwareScreenSize.height - hardwareScreenSize.height ) / 2), hardwareScreenSize.width, hardwareScreenSize.height)];


// this scales overlayImage to fit ontop of camera image
[(UIImage *)overlayImage drawInRect:CGRectMake(0, 0, hardwareScreenSize.width, hardwareScreenSize.height)];

UIImage *finalImage = UIGraphicsGetImageFromCurrentImageContext();
[finalImage retain];

UIGraphicsEndImageContext();