Etiqueta sob imagem em UIButton

Estou tentando criar um botão que tenha algum texto abaixo do ícone (como os botões do aplicativo), no entanto, parece ser bastante difícil de alcançar. Alguma idéia de como posso obter o texto a ser exibido abaixo da imagem com a UIButton?

Ou você pode apenas usar esta categoria:

ObjC

@interface UIButton (VerticalLayout)

- (void)centerVerticallyWithPadding:(float)padding;
- (void)centerVertically;

@end

@implementation UIButton (VerticalLayout)

- (void)centerVerticallyWithPadding:(float)padding {
    CGSize imageSize = self.imageView.frame.size;
    CGSize titleSize = self.titleLabel.frame.size;
    CGFloat totalHeight = (imageSize.height + titleSize.height + padding);
    
    self.imageEdgeInsets = UIEdgeInsetsMake(- (totalHeight - imageSize.height),
                                            0.0f,
                                            0.0f,
                                            - titleSize.width);
    
    self.titleEdgeInsets = UIEdgeInsetsMake(0.0f,
                                            - imageSize.width,
                                            - (totalHeight - titleSize.height),
                                            0.0f);
    
    self.contentEdgeInsets = UIEdgeInsetsMake(0.0f,
                                              0.0f,
                                              titleSize.height,
                                              0.0f);
}

- (void)centerVertically {
    const CGFloat kDefaultPadding = 6.0f;
    [self centerVerticallyWithPadding:kDefaultPadding];
}

@end

Extensão rápida

extension UIButton {
    
    func centerVertically(padding: CGFloat = 6.0) {
        guard
            let imageViewSize = self.imageView?.frame.size,
            let titleLabelSize = self.titleLabel?.frame.size else {
            return
        }
        
        let totalHeight = imageViewSize.height + titleLabelSize.height + padding
        
        self.imageEdgeInsets = UIEdgeInsets(
            top: -(totalHeight - imageViewSize.height),
            left: 0.0,
            bottom: 0.0,
            right: -titleLabelSize.width
        )
        
        self.titleEdgeInsets = UIEdgeInsets(
            top: 0.0,
            left: -imageViewSize.width,
            bottom: -(totalHeight - titleLabelSize.height),
            right: 0.0
        )
        
        self.contentEdgeInsets = UIEdgeInsets(
            top: 0.0,
            left: 0.0,
            bottom: titleLabelSize.height,
            right: 0.0
        )
    }
    
}

Sugestão: Se a altura do botão for menor que totalHeight, a imagem traçará bordas externas.

imageEdgeInset.top deveria estar:

max(0, -(totalHeight - imageViewSize.height))

No Xcode, você pode simplesmente definir o Título da borda esquerdo inserido como negativo na largura da imagem. Isso exibirá a etiqueta no centro da imagem.

Para que o rótulo seja exibido abaixo da imagem (como os botões do aplicativo), pode ser necessário definir a Inserção superior do título da borda como um número positivo.

Este é um botão de título centralizado simples implementado no Swift, substituindo titleRect(forContentRect:)e imageRect(forContentRect:). Também é implementado intrinsicContentSizepara uso com o AutoLayout.

import UIKit

class CenteredButton: UIButton
{
    override func titleRect(forContentRect contentRect: CGRect) -> CGRect {
        let rect = super.titleRect(forContentRect: contentRect)

        return CGRect(x: 0, y: contentRect.height - rect.height + 5,
            width: contentRect.width, height: rect.height)
    }

    override func imageRect(forContentRect contentRect: CGRect) -> CGRect {
        let rect = super.imageRect(forContentRect: contentRect)
        let titleRect = self.titleRect(forContentRect: contentRect)

        return CGRect(x: contentRect.width/2.0 - rect.width/2.0,
            y: (contentRect.height - titleRect.height)/2.0 - rect.height/2.0,
            width: rect.width, height: rect.height)
    }

    override var intrinsicContentSize: CGSize {
        let size = super.intrinsicContentSize

        if let image = imageView?.image {
            var labelHeight: CGFloat = 0.0

            if let size = titleLabel?.sizeThatFits(CGSize(width: self.contentRect(forBounds: self.bounds).width, height: CGFloat.greatestFiniteMagnitude)) {
                labelHeight = size.height
            }

            return CGSize(width: size.width, height: image.size.height + labelHeight + 5)
        }

        return size
    }

    override init(frame: CGRect) {
        super.init(frame: frame)
        centerTitleLabel()
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        centerTitleLabel()
    }

    private func centerTitleLabel() {
        self.titleLabel?.textAlignment = .center
    }
}

Veja esta ótima resposta em Swift.

extension UIButton {

    func alignImageAndTitleVertically(padding: CGFloat = 6.0) {
        let imageSize = self.imageView!.frame.size
        let titleSize = self.titleLabel!.frame.size
        let totalHeight = imageSize.height + titleSize.height + padding

        self.imageEdgeInsets = UIEdgeInsets(
            top: -(totalHeight - imageSize.height),
            left: 0,
            bottom: 0,
            right: -titleSize.width
        )

        self.titleEdgeInsets = UIEdgeInsets(
            top: 0,
            left: -imageSize.width,
            bottom: -(totalHeight - titleSize.height),
            right: 0
        )
    }

}

Subclasse UIButton. Substituir - layoutSubviewspara mover o built-in subviewspara novas posições:

- (void)layoutSubviews
{
    [super layoutSubviews];

    CGRect frame = self.imageView.frame;
    frame = CGRectMake(truncf((self.bounds.size.width - frame.size.width) / 2), 0.0f, frame.size.width, frame.size.height);
    self.imageView.frame = frame;

    frame = self.titleLabel.frame;
    frame = CGRectMake(truncf((self.bounds.size.width - frame.size.width) / 2), self.bounds.size.height - frame.size.height, frame.size.width, frame.size.height);
    self.titleLabel.frame = frame;
}

Resposta refecored icecrystal23.

O Swift 3, funciona com layouts automáticos, xib, storyboards, pode ser animado.

O botão na resposta original do icecrystal23 tinha um quadro mal calculado. Eu acho que consertei isso.

Edit: Atualizado para o Swift 5 e realizado dentro do Interface Builder / Storyboards

import UIKit

@IBDesignable
class VerticalButton: UIButton {

    @IBInspectable public var padding: CGFloat = 20.0 {
        didSet {
            setNeedsLayout()
        }
    }

    override var intrinsicContentSize: CGSize {
        let maxSize = CGSize(width: CGFloat.greatestFiniteMagnitude, height: CGFloat.greatestFiniteMagnitude)

        if let titleSize = titleLabel?.sizeThatFits(maxSize), let imageSize = imageView?.sizeThatFits(maxSize) {
            let width = ceil(max(imageSize.width, titleSize.width))
            let height = ceil(imageSize.height + titleSize.height + padding)

            return CGSize(width: width, height: height)
        }

        return super.intrinsicContentSize
    }

    override func layoutSubviews() {
        if let image = imageView?.image, let title = titleLabel?.attributedText {
            let imageSize = image.size
            let titleSize = title.size()

            titleEdgeInsets = UIEdgeInsets(top: 0.0, left: -imageSize.width, bottom: -(imageSize.height + padding), right: 0.0)
            imageEdgeInsets = UIEdgeInsets(top: -(titleSize.height + padding), left: 0.0, bottom: 0.0, right: -titleSize.width)
        }

        super.layoutSubviews()
    }

}

corrigiu uma das respostas aqui:

Swift 3:

class CenteredButton: UIButton
{
    override func titleRect(forContentRect contentRect: CGRect) -> CGRect {
        let rect = super.titleRect(forContentRect: contentRect)
        let imageRect = super.imageRect(forContentRect: contentRect)

        return CGRect(x: 0, y: imageRect.maxY + 10,
                      width: contentRect.width, height: rect.height)
    }

    override func imageRect(forContentRect contentRect: CGRect) -> CGRect {
        let rect = super.imageRect(forContentRect: contentRect)
        let titleRect = self.titleRect(forContentRect: contentRect)

        return CGRect(x: contentRect.width/2.0 - rect.width/2.0,
                      y: (contentRect.height - titleRect.height)/2.0 - rect.height/2.0,
                      width: rect.width, height: rect.height)
    }

    override init(frame: CGRect) {
        super.init(frame: frame)
        centerTitleLabel()
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        centerTitleLabel()
    }

    private func centerTitleLabel() {
        self.titleLabel?.textAlignment = .center
    }
}

Esta é uma versão modificada da excelente resposta de Erik W. Mas, em vez de colocar a imagem centralizada na parte superior da visualização, ela coloca a imagem e o rótulo centralizados na visualização como um grupo.

A diferença é:

+-----------+
|    ( )    |
|   Hello   |     // Erik W's code
|           |
|           |
+-----------+

vs

+-----------+
|           |
|    ( )    |     // My modified version
|   Hello   |
|           |
+-----------+

Fonte abaixo:

-(void)layoutSubviews {
    [super layoutSubviews];

    CGRect titleLabelFrame = self.titleLabel.frame;
    CGSize labelSize = [self.titleLabel.text sizeWithFont:self.titleLabel.font constrainedToSize:CGSizeMake(self.frame.size.width, CGFLOAT_MAX) lineBreakMode:NSLineBreakByWordWrapping];

    CGRect imageFrame = self.imageView.frame;

    CGSize fitBoxSize = (CGSize){.height = labelSize.height + kTextTopPadding +  imageFrame.size.height, .width = MAX(imageFrame.size.width, labelSize.width)};

    CGRect fitBoxRect = CGRectInset(self.bounds, (self.bounds.size.width - fitBoxSize.width)/2, (self.bounds.size.height - fitBoxSize.height)/2);

    imageFrame.origin.y = fitBoxRect.origin.y;
    imageFrame.origin.x = CGRectGetMidX(fitBoxRect) - (imageFrame.size.width/2);
    self.imageView.frame = imageFrame;

    // Adjust the label size to fit the text, and move it below the image

    titleLabelFrame.size.width = labelSize.width;
    titleLabelFrame.size.height = labelSize.height;
    titleLabelFrame.origin.x = (self.frame.size.width / 2) - (labelSize.width / 2);
    titleLabelFrame.origin.y = fitBoxRect.origin.y + imageFrame.size.height + kTextTopPadding;
    self.titleLabel.frame = titleLabelFrame;
}

FYI: Isso pode ser interrompido quando combinado com as animações do UIView, como layoutSubviews é chamado durante elas.

A solução de Dave em Swift:

override func layoutSubviews() {
    super.layoutSubviews()
    if let imageView = self.imageView {
        imageView.frame.origin.x = (self.bounds.size.width - imageView.frame.size.width) / 2.0
        imageView.frame.origin.y = 0.0
    }
    if let titleLabel = self.titleLabel {
        titleLabel.frame.origin.x = (self.bounds.size.width - titleLabel.frame.size.width) / 2.0
        titleLabel.frame.origin.y = self.bounds.size.height - titleLabel.frame.size.height
    }
}

Se você subclasse UIButtoneoverride layoutSubviews , poderá usar o abaixo para centralizar a imagem e colocar o título centralizado abaixo dela:

kTextTopPadding é uma constante que você precisará introduzir que determina o espaço entre a imagem e o texto abaixo dela.

-(void)layoutSubviews {
    [super layoutSubviews];

    // Move the image to the top and center it horizontally
    CGRect imageFrame = self.imageView.frame;
    imageFrame.origin.y = 0;
    imageFrame.origin.x = (self.frame.size.width / 2) - (imageFrame.size.width / 2);
    self.imageView.frame = imageFrame;

    // Adjust the label size to fit the text, and move it below the image
    CGRect titleLabelFrame = self.titleLabel.frame;
    CGSize labelSize = [self.titleLabel.text sizeWithFont:self.titleLabel.font
                                        constrainedToSize:CGSizeMake(self.frame.size.width, CGFLOAT_MAX)
                                        lineBreakMode:NSLineBreakByWordWrapping];
    titleLabelFrame.size.width = labelSize.width;
    titleLabelFrame.size.height = labelSize.height;
    titleLabelFrame.origin.x = (self.frame.size.width / 2) - (labelSize.width / 2);
    titleLabelFrame.origin.y = self.imageView.frame.origin.y + self.imageView.frame.size.height + kTextTopPadding;
    self.titleLabel.frame = titleLabelFrame;

}

Atualização da resposta de Kenny Winker, pois sizeWithFont foi preterido no iOS 7.

-(void)layoutSubviews {
[super layoutSubviews];

int kTextTopPadding = 3;

CGRect titleLabelFrame = self.titleLabel.frame;

CGRect labelSize = [self.titleLabel.text boundingRectWithSize:CGSizeMake(CGFLOAT_MAX, CGRectGetHeight(self.bounds)) options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName:self.titleLabel.font} context:nil];

CGRect imageFrame = self.imageView.frame;

CGSize fitBoxSize = (CGSize){.height = labelSize.size.height + kTextTopPadding +  imageFrame.size.height, .width = MAX(imageFrame.size.width, labelSize.size.width)};

CGRect fitBoxRect = CGRectInset(self.bounds, (self.bounds.size.width - fitBoxSize.width)/2, (self.bounds.size.height - fitBoxSize.height)/2);

imageFrame.origin.y = fitBoxRect.origin.y;
imageFrame.origin.x = CGRectGetMidX(fitBoxRect) - (imageFrame.size.width/2);
self.imageView.frame = imageFrame;

// Adjust the label size to fit the text, and move it below the image

titleLabelFrame.size.width = labelSize.size.width;
titleLabelFrame.size.height = labelSize.size.height;
titleLabelFrame.origin.x = (self.frame.size.width / 2) - (labelSize.size.width / 2);
titleLabelFrame.origin.y = fitBoxRect.origin.y + imageFrame.size.height + kTextTopPadding;
self.titleLabel.frame = titleLabelFrame;
}

No iOS 11 / Swift 4, nenhuma das respostas acima realmente funcionou para mim. Encontrei alguns exemplos e coloquei meu giro:

extension UIButton {

    func centerImageAndButton(_ gap: CGFloat, imageOnTop: Bool) {

      guard let imageView = self.currentImage,
      let titleLabel = self.titleLabel?.text else { return }

      let sign: CGFloat = imageOnTop ? 1 : -1
      self.titleEdgeInsets = UIEdgeInsetsMake((imageView.size.height + gap) * sign, -imageView.size.width, 0, 0);

      let titleSize = titleLabel.size(withAttributes:[NSAttributedStringKey.font: self.titleLabel!.font!])
      self.imageEdgeInsets = UIEdgeInsetsMake(-(titleSize.height + gap) * sign, 0, 0, -titleSize.width)
    }
}

Espero que isso ajude alguém.

Usando o código de Kenny Winker e simeon, faço esse código rápido que funciona para mim.

import UIKit

@IBDesignable
class TopIconButton: UIButton {
    override func layoutSubviews() {
        super.layoutSubviews()

        let kTextTopPadding:CGFloat = 3.0;

        var titleLabelFrame = self.titleLabel!.frame;


        let labelSize = titleLabel!.sizeThatFits(CGSizeMake(CGRectGetWidth(self.contentRectForBounds(self.bounds)), CGFloat.max))

        var imageFrame = self.imageView!.frame;

        let fitBoxSize = CGSizeMake(max(imageFrame.size.width, labelSize.width), labelSize.height + kTextTopPadding + imageFrame.size.    height)

        let fitBoxRect = CGRectInset(self.bounds, (self.bounds.size.width - fitBoxSize.width)/2, (self.bounds.size.height - fitBoxSize.    height)/2);

        imageFrame.origin.y = fitBoxRect.origin.y;
        imageFrame.origin.x = CGRectGetMidX(fitBoxRect) - (imageFrame.size.width/2);
        self.imageView!.frame = imageFrame;

        // Adjust the label size to fit the text, and move it below the image

        titleLabelFrame.size.width = labelSize.width;
        titleLabelFrame.size.height = labelSize.height;
        titleLabelFrame.origin.x = (self.frame.size.width / 2) - (labelSize.width / 2);
        titleLabelFrame.origin.y = fitBoxRect.origin.y + imageFrame.size.height + kTextTopPadding;
        self.titleLabel!.frame = titleLabelFrame;
        self.titleLabel!.textAlignment = .Center
    }

}

Você só precisa ajustar as três inserções de borda com base no tamanho da imagem e no rótulo do título:

button.contentEdgeInsets = UIEdgeInsetsMake(0, 0, titleLabelBounds.height + 4, 0)
button.titleEdgeInsets = UIEdgeInsetsMake(image.size.height + 8, -image.size.width, 0, 0)
button.imageEdgeInsets = UIEdgeInsetsMake(0, 0, 0, -titleLabelBounds.width)

Você pode obter os limites do rótulo do título chamando sizeToFit após definir o texto. O espaçamento horizontal deve funcionar independentemente do tamanho do texto, fonte e imagem, mas não conheço uma solução única para manter consistente o espaçamento vertical e a borda do conteúdo inferior.

Aqui está a resposta de "Bear With Me" como uma subclasse em Swift 2.0. Para usá-lo, basta alterar sua classe de botão Interface BuilderparaVerticalButton e ele atualizará magicamente a visualização.

Também o atualizei para calcular o tamanho correto do conteúdo intrínseco para o autolayout.

import UIKit

@IBDesignable

class VerticalButton: UIButton {
    @IBInspectable var padding: CGFloat = 8

    override func prepareForInterfaceBuilder() {
        super.prepareForInterfaceBuilder()

        update()
    }

    override func layoutSubviews() {
        super.layoutSubviews()

        update()
    }

    func update() {
        let imageBounds = self.imageView!.bounds
        let titleBounds = self.titleLabel!.bounds
        let totalHeight = CGRectGetHeight(imageBounds) + padding + CGRectGetHeight(titleBounds)

        self.imageEdgeInsets = UIEdgeInsets(
            top: -(totalHeight - CGRectGetHeight(imageBounds)),
            left: 0,
            bottom: 0,
            right: -CGRectGetWidth(titleBounds)
        )

        self.titleEdgeInsets = UIEdgeInsets(
            top: 0,
            left: -CGRectGetWidth(imageBounds),
            bottom: -(totalHeight - CGRectGetHeight(titleBounds)),
            right: 0
        )
    }

    override func intrinsicContentSize() -> CGSize {
        let imageBounds = self.imageView!.bounds
        let titleBounds = self.titleLabel!.bounds

        let width = CGRectGetWidth(imageBounds) > CGRectGetWidth(titleBounds) ? CGRectGetWidth(imageBounds) : CGRectGetWidth(titleBounds)
        let height = CGRectGetHeight(imageBounds) + padding + CGRectGetHeight(titleBounds)

        return CGSizeMake(width, height)
    }
}

@Tiago Eu mudo sua resposta assim. Funciona bem com todos os tamanhos

func alignImageAndTitleVertically(padding: CGFloat = 5.0) {
        self.sizeToFit()
        let imageSize = self.imageView!.frame.size
        let titleSize = self.titleLabel!.frame.size
        let totalHeight = imageSize.height + titleSize.height + padding

        self.imageEdgeInsets = UIEdgeInsets(
            top: -(totalHeight - imageSize.height),
            left: 0,
            bottom: 0,
            right: -titleSize.width
        )

        self.titleEdgeInsets = UIEdgeInsets(
            top: 0,
            left: 0,
            bottom: -(totalHeight - titleSize.height),
            right: titleSize.height
        )
    }

Peguei uma combinação das respostas aqui e criei uma que parece estar funcionando para mim, em Swift. Eu não amo como acabei de substituir as inserções, mas funciona. Eu estaria aberto a melhorias sugeridas nos comentários. Parece funcionar corretamente com sizeToFit()e com layout automático.

import UIKit

/// A button that displays an image centered above the title.  This implementation 
/// only works when both an image and title are set, and ignores
/// any changes you make to edge insets.
class CenteredButton: UIButton
{
    let padding: CGFloat = 0.0

    override func layoutSubviews() {
        if imageView?.image != nil && titleLabel?.text != nil {
            let imageSize: CGSize = imageView!.image!.size
            titleEdgeInsets = UIEdgeInsetsMake(0.0, -imageSize.width, -(imageSize.height + padding), 0.0)
            let labelString = NSString(string: titleLabel!.text!)
            let titleSize = labelString.sizeWithAttributes([NSFontAttributeName: titleLabel!.font])
            imageEdgeInsets = UIEdgeInsetsMake(-(titleSize.height + padding), 0.0, 0.0, -titleSize.width)
            let edgeOffset = abs(titleSize.height - imageSize.height) / 2.0;
            contentEdgeInsets = UIEdgeInsetsMake(edgeOffset, 0.0, edgeOffset, 0.0)
        }
        super.layoutSubviews()
    }

    override func sizeThatFits(size: CGSize) -> CGSize {
        let defaultSize = super.sizeThatFits(size)
        if let titleSize = titleLabel?.sizeThatFits(size),
        let imageSize = imageView?.sizeThatFits(size) {
            return CGSize(width: ceil(max(imageSize.width, titleSize.width)), height: ceil(imageSize.height + titleSize.height + padding))
        }
        return defaultSize
    }

    override func intrinsicContentSize() -> CGSize {
        let size = sizeThatFits(CGSize(width: CGFloat.max, height: CGFloat.max))
        return size
    }
}

Use estes dois métodos:

func titleRect(forContentRect contentRect: CGRect) -> CGRect
func imageRect(forContentRect contentRect: CGRect) -> CGRect

Exemplo:

class VerticalButton: UIButton {

  override func titleRect(forContentRect contentRect: CGRect) -> CGRect {
    let titleRect = super.titleRect(forContentRect: contentRect)
    let imageRect = super.imageRect(forContentRect: contentRect)

    return CGRect(x: 0,
                  y: contentRect.height - (contentRect.height - padding - imageRect.size.height - titleRect.size.height) / 2 - titleRect.size.height,
                  width: contentRect.width,
                  height: titleRect.height)
  }

  override func imageRect(forContentRect contentRect: CGRect) -> CGRect {
    let imageRect = super.imageRect(forContentRect: contentRect)
    let titleRect = self.titleRect(forContentRect: contentRect)

    return CGRect(x: contentRect.width/2.0 - imageRect.width/2.0,
                  y: (contentRect.height - padding - imageRect.size.height - titleRect.size.height) / 2,
                  width: imageRect.width,
                  height: imageRect.height)
  }

  private let padding: CGFloat
  init(padding: CGFloat) {
    self.padding = padding

    super.init(frame: .zero)
    self.titleLabel?.textAlignment = .center
  }

  required init?(coder aDecoder: NSCoder) { fatalError() }
}

extension UIButton {

  static func vertical(padding: CGFloat) -> UIButton {
    return VerticalButton(padding: padding)
  }
}

E você pode usar:

let myButton = UIButton.vertical(padding: 6)

Swift 5 - o método abaixo funciona para mim

func centerVerticallyWithPadding(padding : CGFloat) {
        guard
            let imageViewSize = self.imageView?.frame.size,
            let titleLabelSize = self.titleLabel?.frame.size else {
            return
        }

        let totalHeight = imageViewSize.height + titleLabelSize.height + padding

        self.imageEdgeInsets = UIEdgeInsets(
            top: max(0, -(totalHeight - imageViewSize.height)),
            left: 0.0,
            bottom: 0.0,
            right: -titleLabelSize.width
        )

        self.titleEdgeInsets = UIEdgeInsets(
            top: (totalHeight - imageViewSize.height),
            left: -imageViewSize.width,
            bottom: -(totalHeight - titleLabelSize.height),
            right: 0.0
        )

        self.contentEdgeInsets = UIEdgeInsets(
            top: 0.0,
            left: 0.0,
            bottom: titleLabelSize.height,
            right: 0.0
        )
    }

Verifique se o título do botão não está truncado no storyboard / xib, senão vá para a
Solução 2

class SVVerticalButton: UIButton {

    override func layoutSubviews() {
        super.layoutSubviews()
        let padding : CGFloat = 2.0
        if let imageView = self.imageView {
            imageView.frame.origin.x = (self.bounds.size.width - imageView.frame.size.width) / 2.0
            imageView.frame.origin.y = max(0,(self.bounds.size.height - (imageView.frame.size.height + (titleLabel?.frame.size.height ?? 0.0) + padding)) / 2.0)
        }
        if let titleLabel = self.titleLabel {
            titleLabel.frame.origin.x = 0
            titleLabel.frame.origin.y = self.bounds.size.height - titleLabel.frame.size.height
            titleLabel.frame.size.width = self.bounds.size.width
            titleLabel.textAlignment = .center
        }
    }

}

Achei que a resposta de Simeon era provavelmente a melhor, mas estava me dando resultados estranhos em alguns botões e eu simplesmente não conseguia entender o porquê. Então, usando sua resposta como base, implementei meus botões conforme abaixo:

#define PADDING 2.0f

@implementation OOButtonVerticalImageText

-(CGSize) intrinsicContentSize {
  CGSize size = [super intrinsicContentSize];
  CGFloat labelHeight = 0.0f;
  CGSize titleSize = [self.titleLabel sizeThatFits:CGSizeMake([self contentRectForBounds:self.bounds].size.width, CGFLOAT_MAX)];
  labelHeight = titleSize.height;
  return CGSizeMake(MAX(titleSize.width, self.imageView.image.size.width), self.imageView.image.size.height + labelHeight + PADDING);
}

-(void) layoutSubviews {
  [super layoutSubviews];

  CGSize titleSize = [self.titleLabel sizeThatFits:CGSizeMake([self contentRectForBounds:self.bounds].size.width, CGFLOAT_MAX)];
  self.titleLabel.frame = CGRectMake((self.bounds.size.width - titleSize.width)/2.0f,
                                     self.bounds.size.height - titleSize.height - PADDING,
                                     titleSize.width,
                                     titleSize.height);

  CGSize ivSize = self.imageView.frame.size;
  self.imageView.frame = CGRectMake((self.bounds.size.width - ivSize.width)/2.0f,
                                    self.titleLabel.frame.origin.y - ivSize.height - PADDING,
                                    ivSize.width,
                                    ivSize.height);
}

@end

Aqui está minha subclasse da UIButtonqual resolve esse problema:

@implementation MyVerticalButton

@synthesize titleAtBottom; // BOOL property

- (id)initWithFrame:(CGRect)frame
{
  self = [super initWithFrame:frame];
  if (self) {
    self.titleAtBottom = YES;
  }
  return self;
}

- (CGSize)sizeThatFits:(CGSize)size {
  self.titleLabel.text = [self titleForState: self.state];

  UIEdgeInsets imageInsets = self.imageEdgeInsets;
  UIEdgeInsets titleInsets = self.titleEdgeInsets;

  CGSize imageSize = [self imageForState: self.state].size;
  if (!CGSizeEqualToSize(imageSize, CGSizeZero)) {
    imageSize.width += imageInsets.left + imageInsets.right;
    imageSize.height += imageInsets.top + imageInsets.bottom;

  }

  CGSize textSize = [self.titleLabel sizeThatFits: CGSizeMake(size.width - titleInsets.left - titleInsets.right,
                                                              size.height -(imageSize.width +
                                                                            titleInsets.top+titleInsets.bottom))];
  if (!CGSizeEqualToSize(textSize, CGSizeZero)) {
    textSize.width += titleInsets.left + titleInsets.right;
    textSize.height += titleInsets.top + titleInsets.bottom;
  }

  CGSize result = CGSizeMake(MAX(textSize.width, imageSize.width),
                             textSize.height + imageSize.height);
  return result;
}

- (void)layoutSubviews {
  // needed to update all properities of child views:
  [super layoutSubviews];

  CGRect bounds = self.bounds;

  CGRect titleFrame = UIEdgeInsetsInsetRect(bounds, self.titleEdgeInsets);
  CGRect imageFrame = UIEdgeInsetsInsetRect(bounds, self.imageEdgeInsets);
  if (self.titleAtBottom) {
    CGFloat titleHeight = [self.titleLabel sizeThatFits: titleFrame.size].height;
    titleFrame.origin.y = CGRectGetMaxY(titleFrame)-titleHeight;
    titleFrame.size.height = titleHeight;
    titleFrame = CGRectStandardize(titleFrame);
    self.titleLabel.frame = titleFrame;

    CGFloat imageBottom = CGRectGetMinY(titleFrame)-(self.titleEdgeInsets.top+self.imageEdgeInsets.bottom);
    imageFrame.size.height = imageBottom - CGRectGetMinY(imageFrame);
    self.imageView.frame = CGRectStandardize(imageFrame);
  } else {
    CGFloat titleHeight = [self.titleLabel sizeThatFits: titleFrame.size].height;
    titleFrame.size.height = titleHeight;
    titleFrame = CGRectStandardize(titleFrame);
    self.titleLabel.frame = titleFrame;

    CGFloat imageTop = CGRectGetMaxY(titleFrame)+(self.titleEdgeInsets.bottom+self.imageEdgeInsets.top);
    imageFrame.size.height = CGRectGetMaxY(imageFrame) - imageTop;
    self.imageView.frame = CGRectStandardize(imageFrame);
  }
}

- (void)setTitleAtBottom:(BOOL)newTitleAtBottom {
  if (titleAtBottom!=newTitleAtBottom) {
    titleAtBottom=newTitleAtBottom;
    [self setNeedsLayout];
  }
}

@end

É isso aí. Funciona como charme. O problema pode aparecer se o botão for pequeno demais para caber no título e no texto.

Eu acho que uma das melhores maneiras de fazer isso é subclassificar UIButton e substituir alguns métodos de renderização:

- (void)awakeFromNib
{
    [super awakeFromNib];
    [self setupSubViews];
}

- (instancetype)init
{
    if (self = [super init])
    {
        [self setupSubViews];
    }
    return self;
}

- (void)setupSubViews
{
    [self.imageView setTranslatesAutoresizingMaskIntoConstraints:NO];
    [self addConstraint:[NSLayoutConstraint constraintWithItem:self attribute:NSLayoutAttributeCenterX relatedBy:NSLayoutRelationEqual toItem:self.imageView attribute:NSLayoutAttributeCenterX multiplier:1 constant:0]];
    [self.titleLabel setTranslatesAutoresizingMaskIntoConstraints:NO];
    [self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|[imageView][titleLabel]|" options:NSLayoutFormatAlignAllCenterX metrics:nil views:@{@"imageView": self.imageView, @"titleLabel": self.titleLabel}]];
}

- (CGSize)intrinsicContentSize
{
    CGSize imageSize = self.imageView.image.size;
    CGSize titleSize = [self.titleLabel.text sizeWithAttributes:@{NSFontAttributeName: self.titleLabel.font}];
    return CGSizeMake(MAX(imageSize.width, titleSize.width), imageSize.height + titleSize.height);
}

solução do @ simeon em Objective-C

#import "CenteredButton.h"

@implementation CenteredButton

- (CGRect)titleRectForContentRect:(CGRect)contentRect
{
    CGRect rect = [super titleRectForContentRect: contentRect];
    return CGRectMake(0,
                      contentRect.size.height - rect.size.height - 5,
                      contentRect.size.width,
                      rect.size.height);
}

- (CGRect)imageRectForContentRect:(CGRect)contentRect
{
    CGRect rect = [super imageRectForContentRect: contentRect];
    CGRect titleRect = [self titleRectForContentRect: contentRect];

    return CGRectMake(contentRect.size.width / 2.0 - rect.size.width / 2.0,
                      (contentRect.size.height - titleRect.size.height)/2.0 - rect.size.height/2.0,
                      rect.size.width,
                      rect.size.height);
}

- (CGSize)intrinsicContentSize {
    CGSize imageSize = [super intrinsicContentSize];

    if (self.imageView.image) {
        UIImage* image = self.imageView.image;
        CGFloat labelHeight = 0.0;

        CGSize labelSize = [self.titleLabel sizeThatFits: CGSizeMake([self contentRectForBounds: self.bounds].size.width, CGFLOAT_MAX)];
        if (CGSizeEqualToSize(imageSize, labelSize)) {
            labelHeight = imageSize.height;
        }

        return CGSizeMake(MAX(labelSize.width, imageSize.width), image.size.height + labelHeight + 5);
    }

    return imageSize;
}

- (id) initWithFrame:(CGRect)frame {
    self = [super initWithFrame:frame];
     if (self) {
         [self centerTitleLabel];
     }
    return self;

}

- (id)initWithCoder:(NSCoder *)aDecoder {
    self = [super initWithCoder:aDecoder];
    if (self) {
        [self centerTitleLabel];
    }
    return self;
}

- (void)centerTitleLabel {
    self.titleLabel.textAlignment = NSTextAlignmentCenter;
}

@end

Se você estiver usando fontes personalizadas, o cálculo para o tamanho do titleLabel não funcionará corretamente, substitua-o por

let titleLabelSize = self.titleLabel?.text?.size(withAttributes: [NSAttributedStringKey.font: self.titleLabel!.font!])

Em vez de passar pelo inferno tentando posicionar o ícone e o texto com bordas, você pode criar um NSAttributedString com sua imagem como anexo e configurá-lo para o título atribuído ao botão:

let titleText = NSAttributedString(string: yourTitle, attributes: attributes)
let imageAttachment = NSTextAttachment()
imageAttachment.image = yourImage

let title = NSMutableAttributedString(string: "")
title.append(NSAttributedString(attachment: imageAttachment))
title.append(titleText)

button.setAttributedTitle(title, for: .normal)

Solução amigável para localização:

Tantas ótimas soluções, pessoal, mas gostaria de adicionar uma nota aqui para quem usa a localização.

Você precisa reverter os valores EdgeInstets esquerdo e direito para obter o botão corretamente disposto em caso de alteração da direção do idioma de LtR para RtL.

Usando uma solução semelhante, eu a implementaria da seguinte maneira:

extension UIButton {

    func alignVertical(spacing: CGFloat, lang: String) {
        guard let imageSize = self.imageView?.image?.size,
            let text = self.titleLabel?.text,
            let font = self.titleLabel?.font
        else { return }

        let labelString = NSString(string: text)
        let titleSize = labelString.size(
            withAttributes: [NSAttributedString.Key.font: font]
        )

        var titleLeftInset: CGFloat = -imageSize.width
        var titleRigtInset: CGFloat = 0.0

        var imageLeftInset: CGFloat = 0.0
        var imageRightInset: CGFloat = -titleSize.width

        if Locale.current.languageCode! != "en" { // If not Left to Right language
            titleLeftInset = 0.0
            titleRigtInset = -imageSize.width

            imageLeftInset = -titleSize.width
            imageRightInset = 0.0
        }

        self.titleEdgeInsets = UIEdgeInsets(
            top: 0.0,
            left: titleLeftInset,
            bottom: -(imageSize.height + spacing),
            right: titleRigtInset
        )
        self.imageEdgeInsets = UIEdgeInsets(
            top: -(titleSize.height + spacing),
            left: imageLeftInset,
            bottom: 0.0,
            right: imageRightInset
        )
        let edgeOffset = abs(titleSize.height - imageSize.height) / 2.0;
        self.contentEdgeInsets = UIEdgeInsets(
            top: edgeOffset,
            left: 0.0,
            bottom: edgeOffset,
            right: 0.0
        )
    }
}

Imagem superior e botão de título inferior com subclasse UIButton

class VerticalButton: UIButton {
  override func layoutSubviews() {
    super.layoutSubviews()
    let padding: CGFloat = 8
    let iH = imageView?.frame.height ?? 0
    let tH = titleLabel?.frame.height ?? 0
    let v: CGFloat = (frame.height - iH - tH - padding) / 2
    if let iv = imageView {
      let x = (frame.width - iv.frame.width) / 2
      iv.frame.origin.y = v
      iv.frame.origin.x = x
    }

    if let tl = titleLabel {
      let x = (frame.width - tl.frame.width) / 2
      tl.frame.origin.y = frame.height - tl.frame.height - v
      tl.frame.origin.x = x
    }
  }
}

Definitivamente, isso é um exagero para esta pergunta ... Em um dos meus projetos, primeiro tive que implementar um botão com o ícone alinhado à esquerda. Então nós temos outro botão com o título abaixo da imagem. Procurei uma solução existente, mas sem sorte Então, aqui está o botão alinhado:

@IBDesignable
class AlignableButton: UIButton {

override class var requiresConstraintBasedLayout: Bool {
    return true
}

@objc enum IconAlignment: Int {
    case top, left, right, bottom
}

// MARK: - Designables
@IBInspectable var iconAlignmentValue: Int {
    set {
        iconAlignment = IconAlignment(rawValue: newValue) ?? .left
    }
    get {
        return iconAlignment.rawValue
    }
}

var iconAlignment: IconAlignment = .left

@IBInspectable var titleAlignmentValue: Int {
    set {
        titleAlignment = NSTextAlignment(rawValue: newValue) ?? .left
    }
    get {
        return titleAlignment.rawValue
    }
}

var titleAlignment: NSTextAlignment = .left

// MARK: - Corner Radius
@IBInspectable
var cornerRadius: CGFloat {
    get {
        return layer.cornerRadius
    }
    set {
        layer.masksToBounds = (newValue != 0)
        layer.cornerRadius = newValue
    }
}

// MARK: - Content size
override var intrinsicContentSize: CGSize {
    
    switch iconAlignment {
    case .top, .bottom:
        return verticalAlignedIntrinsicContentSize
    
    default:
        return super.intrinsicContentSize
    }
}

private var verticalAlignedIntrinsicContentSize: CGSize {
    
    if let imageSize = imageView?.intrinsicContentSize,
        let labelSize = titleLabel?.intrinsicContentSize {
        
        let width = max(imageSize.width, labelSize.width) + contentEdgeInsets.left + contentEdgeInsets.right
        let height = imageSize.height + labelSize.height + contentEdgeInsets.top + contentEdgeInsets.bottom
        
        return CGSize(
            width: ceil(width),
            height: ceil(height)
        )
    }
    
    return super.intrinsicContentSize
}

// MARK: - Image Rect
override func imageRect(forContentRect contentRect: CGRect) -> CGRect {
    
    switch iconAlignment {
    case .top:
        return topAlignedImageRect(forContentRect: contentRect)
    case .bottom:
        return bottomAlignedImageRect(forContentRect: contentRect)
    case .left:
        return leftAlignedImageRect(forContentRect: contentRect)
    case .right:
        return rightAlignedImageRect(forContentRect: contentRect)
    }
}

func topAlignedImageRect(forContentRect contentRect: CGRect) -> CGRect {
    let rect = super.imageRect(forContentRect: contentRect)
    
    let x = (contentRect.width - rect.width) / 2.0 + contentRect.minX
    let y = contentRect.minY
    let w = rect.width
    let h = rect.height
    
    return CGRect(
        x: x,
        y: y,
        width: w,
        height: h
    ).inset(by: imageEdgeInsets)
}

func bottomAlignedImageRect(forContentRect contentRect: CGRect) -> CGRect {
    let rect = super.imageRect(forContentRect: contentRect)
    
    let x = (contentRect.width - rect.width) / 2.0 + contentRect.minX
    let y = contentRect.height - rect.height + contentRect.minY
    let w = rect.width
    let h = rect.height
    
    return CGRect(
        x: x,
        y: y,
        width: w,
        height: h
    ).inset(by: imageEdgeInsets)
}

func leftAlignedImageRect(forContentRect contentRect: CGRect) -> CGRect {
    let rect = super.imageRect(forContentRect: contentRect)
    
    let x = contentRect.minX
    let y = (contentRect.height - rect.height) / 2 + contentRect.minY
    let w = rect.width
    let h = rect.height
    
    return CGRect(
        x: x,
        y: y,
        width: w,
        height: h
    ).inset(by: imageEdgeInsets)
}

func rightAlignedImageRect(forContentRect contentRect: CGRect) -> CGRect {
    let rect = super.imageRect(forContentRect: contentRect)
    
    let x = (contentRect.width - rect.width) + contentRect.minX
    let y = (contentRect.height - rect.height) / 2 + contentRect.minY
    let w = rect.width
    let h = rect.height
    
    return CGRect(
        x: x,
        y: y,
        width: w,
        height: h
    ).inset(by: imageEdgeInsets)
}

// MARK: - Title Rect
override func titleRect(forContentRect contentRect: CGRect) -> CGRect {
    
    switch iconAlignment {
    case .top:
        return topAlignedTitleRect(forContentRect: contentRect)
    case .bottom:
        return bottomAlignedTitleRect(forContentRect: contentRect)
    case .left:
        return leftAlignedTitleRect(forContentRect: contentRect)
    case .right:
        return rightAlignedTitleRect(forContentRect: contentRect)
    }
}

func topAlignedTitleRect(forContentRect contentRect: CGRect) -> CGRect {
    
    let rect = super.titleRect(forContentRect: contentRect)

    let x = contentRect.minX
    let y = contentRect.height - rect.height + contentRect.minY
    let w = contentRect.width
    let h = rect.height
    
    return CGRect(
        x: x,
        y: y,
        width: w,
        height: h
    ).inset(by: titleEdgeInsets)
}

func bottomAlignedTitleRect(forContentRect contentRect: CGRect) -> CGRect {
    
    let rect = super.titleRect(forContentRect: contentRect)
    
    let x = contentRect.minX
    let y = contentRect.minY
    let w = contentRect.width
    let h = rect.height
    
    return CGRect(
        x: x,
        y: y,
        width: w,
        height: h
    ).inset(by: titleEdgeInsets)
}

func leftAlignedTitleRect(forContentRect contentRect: CGRect) -> CGRect {
    
    let titleRect = super.titleRect(forContentRect: contentRect)
    let imageRect = self.imageRect(forContentRect: contentRect)
    
    let x = imageRect.width + imageRect.minX
    let y = (contentRect.height - titleRect.height) / 2.0 + contentRect.minY
    let w = contentRect.width - imageRect.width * 2.0
    let h = titleRect.height
    
    return CGRect(
        x: x,
        y: y,
        width: w,
        height: h
    ).inset(by: titleEdgeInsets)
}

func rightAlignedTitleRect(forContentRect contentRect: CGRect) -> CGRect {
    
    let titleRect = super.titleRect(forContentRect: contentRect)
    let imageRect = self.imageRect(forContentRect: contentRect)

    let x = contentRect.minX + imageRect.width
    let y = (contentRect.height - titleRect.height) / 2.0 + contentRect.minY
    let w = contentRect.width - imageRect.width * 2.0
    let h = titleRect.height
    
    return CGRect(
        x: x,
        y: y,
        width: w,
        height: h
    ).inset(by: titleEdgeInsets)
}

// MARK: - Lifecycle
override func awakeFromNib() {
    super.awakeFromNib()
    
    titleLabel?.textAlignment = titleAlignment
}

override func prepareForInterfaceBuilder() {
    super.prepareForInterfaceBuilder()
    
    titleLabel?.textAlignment = titleAlignment
}
}