Remove sizeToFit() from SizeCalculable protocol

[antoinelamy]

As per the documentation, we should not directly override sizeToFit() but rather always only implement sizeThatFits(_:) for auto-sizing needs. This PR aim to remove the sizeToFit() requirement in the SizeCalculable protocol.

You should not override this method. If you want to change the default sizing information for your view, override the sizeThatFits(_:) instead. That method performs any needed calculations and returns them to this method, which then makes the change.

Internally, UIView has a very basic implementation of the sizeToFit() method which is the equivalent of calling sizeThatFits with the view bounds so instead of calling it directly, we replicate its behaviour inside PinLayout (the implementation is not gonna change anytime soon anyway).

The original class look like this in assembly pseudo-code:

Once converted into a more human readable form, the implementation source code look like this:

- (void)sizeToFit {
  CGAffineTransform *transform = [self transform];

  if (CGAffineTransformIsIdentity(transform)) {
    CGRect frame = [self frame];
    CGSize size = [self sizeThatFits: CGSizeMake(frame.width, frame.height)];
    [self setFrame: CGRectMake(frame.x, frame.y, size.width, size.height)];
  }
  else {
    CGRect bounds = [self bounds];
    CGSize size = [self sizeThatFits: CGSizeMake(bounds.width, bounds.height)];
    [self setBounds: CGRectMake(bounds.x, bounds.y, size.width, size.height)];
  }
}

[lucdion]

Good catch 👍 We should eventually add more unit tests for objective-c.

[lucdion]

Icchh if case .fitTypeContent = adjustSizeType {} else { 😬. I would prefer a switch case here, even if it is longer, it is cleaner.

[lucdion]

@antoinelamy does this match also the size computed by UILabel.sizeToFit()?

[antoinelamy]

@lucdion sorry it took forever but I finally got the chance to make the requested changes. About your question wether or not it match the size computed by UILabel.sizeToFit(), the answer is yes. I also added tests to ensure they both produce the same result with or without a transform applied.

[lucdion]

Thanks @antoinelamy 🙂