frame altering image size - ios

Question

I'm trying to add my settings button to my toolbar but the frame I have to set for it is altering the image dimensions. How do i set the frame without messing with the image itself. The image is stored in an asset catalog for #1x, #2x, and #3x.
-(void)viewWillAppear:(BOOL)animated{
//Toolbar buttons
UIView *buttonContainer = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 200, 44)];
buttonContainer.backgroundColor = [UIColor clearColor];
UIButton *button0 = [UIButton buttonWithType:UIButtonTypeCustom];
--[button0 setFrame:CGRectMake(0, 0, 44, 44)];-------------
[button0 setBackgroundImage:[UIImage imageNamed:#"settings-128(1).png"] forState:UIControlStateNormal];
[button0 addTarget:self action:#selector(button0Action:) forControlEvents:UIControlEventTouchUpInside];
[button0 setShowsTouchWhenHighlighted:YES];
[buttonContainer addSubview:button0];
self.navigationItem.titleView = buttonContainer;
}

Answer 1

You have a few different options. If you don't absolutely need to make your button a different size than its background image, then you can set the background image and then get a size that will not stretch that background image, to assign to the button's frame, like:
[button0 setBackgroundImage:[UIImage imageNamed:#"settings-128(1).png"] forState:UIControlStateNormal];
const CGSize button0Size = [button0 sizeThatFits:CGSizeZero];
[button0 setFrame:CGRectMake(0, 0, button0Size.width, button0Size.height)];
If you actually want to change the size of your background image without distortion (for example, you might want to elongate the background image by copying pixels in its center) you should look into the resizableImageWithCapInsets: methods provided by UIImage.
If for some reason you need button0 to have a particular frame and you want its background to be a different size, you can subclass UIButton and in your subclass explicitly implement:
- (CGRect)backgroundRectForBounds:(CGRect)bounds
and return a correctly sized frame for your background image regardless of the button's bounds.
And of course, if all else fails, you can pad your asset settings-128(1).png with clear pixels to make the image size match the desired frame size. I don't recommend that approach if you can avoid it since it will cause any future changes to the button's size to require careful changes to the image (and the 2x and 3x versions of the image).