UIButton trimmed text when using bold text

I was able to reproduce this on iOS 13 and on iOS 14 (beta 3) - Filed another feedback (8115220) for this.

I dug a bit further into this and it seems that UIButton isn't reporting the correct intrinsicContentSize when bold text is enabled.

From a small experiment I subclassed UIButton to print out the intrinsicContentSize of the button itself and some of its subviews:

Code Block swift
private class Button: UIButton {
        override var intrinsicContentSize: CGSize {
            let size = super.intrinsicContentSize
            guard let imageView = imageView, let titleLabel = titleLabel else {
                return size
            }
            print("""
            button.intrinsicContentSize = \(size)
                button.titleLabel.intrinsicContentSize = \(titleLabel.intrinsicContentSize)
                button.titleLabel.sizeThatFits = \(titleLabel.sizeThatFits(CGSize(width: .max, height: .max)))
                button.imageView.intrinsicContentSize = \(imageView.intrinsicContentSize)
                button.imageView.sizeThatFits = \(imageView.sizeThatFits(CGSize(width: .max, height: .max)))
            """)
					 return size
        }
    }

For a simple use case:

Code Block swift
    func makeButton() -> UIButton {
        let button = Button(type: .system)
        let image = UIImage(named: "menu")
        button.setImage(image, for: .normal)
        button.setTitle("Menu", for: .normal)
        return button
    }

We get the following results

for Normal Text:

Code Block 
intrinsicContentSize = (68.0, 29.0)
		button.titleLabel..intrinsicContentSize = (38.5, 18.0)
		button.titleLabel..sizeThatFits = (38.5, 18.0)
		button.imageView.intrinsicContentSize = (29.0, 29.0)
		button.imageView.sizeThatFits = (29.0, 29.0)

when Bold Text is enabled:

Code Block 
button.intrinsicContentSize = (69.0, 29.0)
		button.titleLabel.intrinsicContentSize = (40.0, 18.0)
		button.titleLabel.sizeThatFits = (40.0, 18.0)
		button.imageView.intrinsicContentSize = (29.0, 29.0)
		button.imageView.sizeThatFits = (30.0, 30.0)

Notice the button's imageView isn't reporting the correct intrinsicContentSize when bold text is enabled, interestingly it does report the correct size when asking for sizeThatFits!!

A workaround I found is to manually add the size diff to the intrinsic content size of the button, but that isn't fool proof as there could be situations / configurations where that isn't correct.

e.g.

Code Block swift
        override var intrinsicContentSize: CGSize {
            let size = super.intrinsicContentSize
            guard let imageView = imageView else {
                return size
            }
						let imageSizeThatFits = imageView.sizeThatFits(CGSize(width: .max, height: .max))
            let imageIntrinsicSize = imageView.intrinsicContentSize
            let sizeDiff = CGSize(width: imageSizeThatFits.width - imageIntrinsicSize.width,
                                  height: imageSizeThatFits.height - imageIntrinsicSize.height)
            return CGSize(width: size.width + sizeDiff.width,
                          height: size.height + sizeDiff.height)
			 }

I've just noticed this issue myself on iOS 17, and have found that it seems to only truncate the button title when the image uses the template rendering mode.

// The following causes the title to be truncated when bold text is turned on,
// because the image width increases slightly
setImage(myImage.withRenderingMode(.alwaysTemplate), for: .normal)

// The following prevents the image size from changing when bold text is enabled
setImage(myImage.withRenderingMode(.alwaysOriginal), for: .normal) 

Seems like an unusual bug with UIButton, but at least this fix/workaround is simpler than attempting to calculate changes to the intrinsic content size.