how to align my image in the center IOS horizontally

Question

Here is my image :

Obj *obj = ... obj has imageHref which is NSString

UIImage *image = [UIImage imageNamed:[NSString stringWithFormat:obj.imageHref]]; 
[image drawInRect:CGRectMake(0, 0, image.size.width, image.size.height)];

Depending on image size I can't figure out how to center it, any ideas ?

This is all inside method :

- (void)drawRect:(CGRect)rect {    
    Obj *obj = ... obj has imageHref which is NSString

    UIImage *image = [UIImage imageNamed:[NSString stringWithFormat:obj.imageHref]]; 
    [image drawInRect:CGRectMake(0, 0, image.size.width, image.size.height)];

    NSLog(@"%f", rect.size.width);
     NSLog(@"%f", rect.size.height);
}

Where rect.size.width prints 320.000000 and rect.size.height prints 416.000000

Answer 1

This or something very like this should centre horizontally.

CGPoint centerImageView = imageView.center;
centerImageView.x = self.view.center.x;
ImageView.center = centerImageView;

Answer 2

[image drawInRect:CGRectMake((self.view.frame.size.width/2) - (image.size.width/2),
                             (self.view.frame.size.height / 2) - (image.size.height / 2),
                             image.size.width, 
                             image.size.height)];

edit:

As you are already in a UIView:

[image drawInRect:CGRectMake((self.frame.size.width/2) - (image.size.width/2), (self.frame.size.height / 2) - (image.size.height / 2), image.size.width, image.size.height)];

Answer 3

It is possible to add a macro like this before @interface in .h class file
#define COUNTMID(X,Y) (float) (X-Y)/2
and then use it in code as
float center COUNTMID(ParentView.frame.width,ChildView.frame.width)
to place your ChildView view at horizontal center of ParentView
I've also made a method, making a ChildView frame to be placed in the center of ParentView:

-(CGRect) CenterFrameOfView:(UIView *) ParentView forView:(UIView *) ChildView
{
    CGRect result = CGRectMake(COUNTMID(ParentView.frame.size.width,ChildView.frame.size.width),COUNTMID(ParentView.frame.size.height,ChildView.frame.height),ChildView.frame.size.width,ChildView.frame.size.height);
    return result;
}

Or with setFrame

-(void) CenterFrameOfView:(UIView *) ParentView forView:(UIView *) ChildView 
{
    CGRect result = CGRectMake(COUNTMID(ParentView.frame.size.width,ChildView.frame.size.width),COUNTMID(ParentView.frame.size.height,ChildView.frame.height),ChildView.frame.size.width,ChildView.frame.size.height);
    [ChildView setFrame:result];
}

Hope it helps