Resize UIImage programmatically iphone

Question

I want to crop a UIImage that the size of the UIImage is 640*960 and i want to crop it and it will be 640*640.

I try to use this method:

CGImageRef imageRef = CGImageCreateWithImageInRect([largeImage CGImage], cropRect);
// or use the UIImage wherever you like
[UIImageView setImage:[UIImage imageWithCGImage:imageRef]]; 
CGImageRelease(imageRef);]]

and this CGRect : (0,0,640,640) but it give me UIImage that is not 640*640 from the original UIImage

Answer 1

use the following function

        UIImage *newImage = [self imageWithImage:mainDelegate.starImage scaledToSize:CGSizeMake(640, 640)];  

   - (UIImage *)imageWithImage:(UIImage *)image scaledToSize:(CGSize)newSize {
UIGraphicsBeginImageContext(newSize);
[image drawInRect:CGRectMake(0, 0, newSize.width, newSize.height)];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();    
UIGraphicsEndImageContext();
return newImage;
}

This will return the image with size (newSize.width,newSize.height)