iphone - Iphonesdk Merge three images two single image

Question

i am working on iphone app where i have to merge three images and make them single image. I mean to say i have a background image, a header image and lower image, i need to combine all this to make a single image so i can use it to post to the facebook. thanks.

*EDIT* i know this code for two images but how can i use it for three images :

UIGraphicsBeginImageContext(saveView.bounds.size);
[saveView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *finalImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

Answer 1

You can just align them together in a single UIView ( I think even off-screen but I haven't checked yet) - and then just convert that UIView to a UIImage using QuartzCode:

UIGraphicsBeginImageContext(myView.bounds.size);
[myView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

Then turn that into a format - like PNG for instance:

NSData *imageData = UIImagePNGRepresentation(image);

Then sending shouldn't be too difficult.

EDIT Here is an extended example you can also see for 3 images - you can of course use Interface Builder and Outlets instead of writing it all - but you can copy paste this to try:

UIImageView *imgView1, *imgView2, *imgView3;
imgView1 = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"image1"]];
imgView2 = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"image2"]];
imgView3 = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"image3"]];

imgView1.frame = CGRectMake(0, 0, 50, 50);
imgView2.frame = CGRectMake(50, 50, 100, 100);
imgView3.frame = CGRectMake(100, 100, 200, 200);

[referenceView addSubview:imgView1];
[referenceView addSubview:imgView2];
[referenceView addSubview:imgView3];

UIGraphicsBeginImageContext(referenceView.bounds.size);
[referenceView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *finalImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

resultView = [[UIImageView alloc] initWithImage:finalImage];
resultView.frame = CGRectMake(0, 0, 320, 480);
[self.view addSubview:resultView];

referenceView.hidden = YES; 

NOTE I've checked and the UIView must be drawable/visible at the time you call renderInContext (it can be off-screen but it cannot be hidden or alpha=0 because then it will be rendered invisible). So either put it off-screen or immediately hide it after drawing