如何计算iOS 7中的实际字体点大小（不是边界矩形）？

Edit: The linked "duplicate" question only deals with calculating text rectangle. I need to calculate actual font size after label scaled it, NOT the string size.

编辑：链接的“重复”问题仅涉及计算文本矩形。我需要在标签缩放后计算实际字体大小，而不是字符串大小。

This method is now deprecated:

现在不推荐使用此方法：

size = [self sizeWithFont:font // 20
              minFontSize:minFontSize // 14
           actualFontSize:&actualFontSize // 16
                 forWidth:maxWidth
            lineBreakMode:self.lineBreakMode];

How can I calculate font size of a UILabel now in iOS 7 when it shrunk the size of the text to fit in?

现在在iOS 7中缩小文本大小以适应时，如何计算UILabel的字体大小？

8 个解决方案

#1

I have the same problem, I need to know the actual size to make that the others UILabels in my UIView match.

我有同样的问题，我需要知道实际的大小，使我的UIView中的其他UILabel匹配。

I know that it's not a perfect solution, but perhaps it's useful for you.

我知道这不是一个完美的解决方案，但也许它对你有用。

My solution is: instead of use adjustsFontSizeToFitWidth I calculate "manually" the size.

我的解决方案是：而不是使用adjustsFontSizeToFitWidth我计算“手动”的大小。

CGSize initialSize = [_label.text sizeWithAttributes:@{NSFontAttributeName:_label.font}];
while ( initialSize.width > _label.frame.size.width ) {
    [_label setFont:[_label.font fontWithSize:_label.font.pointSize - 1]];
    initialSize = [_label.text sizeWithAttributes:@{NSFontAttributeName:_label.font}];
}
CGFloat actualSize = _label.font.pointSize;

#2

Distilled from Julius Bahr's answer on this page, this method works perfectly for getting the actual font size after it has been automatically adjusted:

根据Julius Bahr在本页面上的回答，这种方法非常适合在自动调整后获得实际字体大小：

- (CGFloat)getActualFontSizeForLabel:(UILabel *)label
{
    NSStringDrawingContext *labelContext = [NSStringDrawingContext new];
    labelContext.minimumScaleFactor = label.minimumScaleFactor;

    NSAttributedString *attributedString = [[NSAttributedString alloc] initWithString:label.text attributes:@{ NSFontAttributeName: label.font }];
    [attributedString boundingRectWithSize:label.frame.size
                                   options:NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading
                                   context:labelContext];

    CGFloat actualFontSize = label.font.pointSize * labelContext.actualScaleFactor;
    return actualFontSize;
}

I am using this in my application to get the font sizes for three different labels for which I need to keep the sizes in synch while still allowing them to auto-shrink for localized translations that can be quite a bit longer than their original English counterparts.

我在我的应用程序中使用它来获取三个不同标签的字体大小，我需要保持大小同步，同时仍然允许它们自动缩小本地化的翻译，这可能比原来的英语版本更长。

I call that method once for each label, and then if they are not all the same value, I set the label's font sizes to the minimum of the three.

我为每个标签调用一次该方法，然后如果它们不是全部相同的值，我将标签的字体大小设置为三者中的最小值。

#3

The use of minFontSize was deprecated on UILabel in iOS 6, and on the NSString drawing additions in iOS 7. If you want to use it and find the actual font size used, you need to use the deprecated method you mentioned in your question.

在iOS 6中的UILabel和iOS 7中的NSString绘图添加中不推荐使用minFontSize。如果要使用它并查找使用的实际字体大小，则需要使用您在问题中提到的弃用方法。

The replacement for minFontSize is minimumScaleFactor. If you want to find the actual scale factor used, you need to create an NSStringDrawingContext and pass it in the boundingRectWithSize:options:attributes:context: message, like this:

minFontSize的替换是minimumScaleFactor。如果要查找使用的实际比例因子，则需要创建NSStringDrawingContext并将其传递给boundingRectWithSize：options：attributes：context：message，如下所示：

NSStringDrawingContext *context = [[NSStringDrawingContext alloc] init];
context.minimumScaleFactor = 0.7;
[label.text boundingRectWithSize:CGSizeMake(maxWidth, HUGE_VAL)
    options:NSStringDrawingUsesLineFragmentOrigin
    attributes:@{
        NSFontAttributeName: font
    } context:context];
CGFloat actualFontSize = font.pointSize * context.actualScaleFactor;

#4

Expanding on Ferran's answer

扩展Ferran的答案

To expand to fill width or height, whichever it hits first

扩展到填充宽度或高度，无论它首先击中

Swift version

Swift版本

func getFontSizeToFitFrameOfLabel(label: UILabel) -> CGFloat
{
    var initialSize : CGSize = label.text!.sizeWithAttributes([NSFontAttributeName : label.font])

    if initialSize.width > label.frame.size.width ||
       initialSize.height > label.frame.size.height
    {
        while initialSize.width > label.frame.size.width ||
              initialSize.height > label.frame.size.height
        {
            label.font = label.font.fontWithSize(label.font.pointSize - 1)
            initialSize = label.text!.sizeWithAttributes([NSFontAttributeName : label.font])
        }
    } else {
        while initialSize.width < label.frame.size.width &&
              initialSize.height < label.frame.size.height
        {
            label.font = label.font.fontWithSize(label.font.pointSize + 1)
            initialSize = label.text!.sizeWithAttributes([NSFontAttributeName : label.font])
        }
        // went 1 point too large so compensate here
        label.font = label.font.fontWithSize(label.font.pointSize - 1)
    }
    return label.font.pointSize;
}

Then do something like this to use it (say your label is named title1Label)

然后做这样的事情来使用它（比如说你的标签叫做title1Label）

 title1Label.frame = CGRect(x: 0.0, y: 0.0, width: view.frame.size.width, height: view.frame.size.height)
 // sets font to some nonzero size to begin with, it will change up or down to fit the label's frame
 title1Label.font = UIFont(name: "Super Mario 256", size: 45.0)
 title1Label.font = title1Label.font.fontWithSize(getFontSizeToFitFrameOfLabel(title1Label))
 // resize height to be a little larger than the font height
 title1Label.frame.size.height = title1Label.font.pointSize*1.3

Objective C version:

Objective C版本：

- (CGFloat) maxFontSize:(UILabel *)label{
   CGSize initialSize = [label.text sizeWithAttributes:@{NSFontAttributeName:label.font}];

   if (initialSize.width > label.frame.size.width ||
       initialSize.height > label.frame.size.height)
   {
       while (initialSize.width > label.frame.size.width ||
              initialSize.height > label.frame.size.height)
       {
           [label setFont:[label.font fontWithSize:label.font.pointSize - 1]];
           initialSize = [label.text sizeWithAttributes:@{NSFontAttributeName:label.font}];
       }
   } else {
       while (initialSize.width < label.frame.size.width &&
              initialSize.height < label.frame.size.height)
       {
           [label setFont:[label.font fontWithSize:label.font.pointSize + 1]];
           initialSize = [label.text sizeWithAttributes:@{NSFontAttributeName:label.font}];
       }
       // went 1 point too large so compensate here
       [label setFont:[label.font fontWithSize:label.font.pointSize - 1]];
   }
   return label.font.pointSize;
}

#5

My specific quest has been to size the font on 2 labels equally with adjustsFontSizeToFitWidth enabled. The solution works on iOS 6 and 7.

我的具体任务是在启用了adjustsFontSizeToFitWidth的情况下，同等地调整2个标签上的字体大小。该解决方案适用于iOS 6和7。

+ (void)sizeLabelFontToMinSizeFor:(UILabel *)label1 and:(UILabel *)label2 {

NSStringDrawingContext *labelContext = [NSStringDrawingContext new];
labelContext.minimumScaleFactor = label1.minimumScaleFactor;

NSAttributedString *attributedString1 = [[NSAttributedString alloc] initWithString:label1.text attributes:@{NSFontAttributeName : label1.font}];
// the NSStringDrawingUsesLineFragmentOrigin and NSStringDrawingUsesFontLeading options are magic
[attributedString1 boundingRectWithSize:label1.frame.size options:NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading context:labelContext];

CGFloat actualFontSize1 = label1.font.pointSize * labelContext.actualScaleFactor;

labelContext = [NSStringDrawingContext new];
labelContext.minimumScaleFactor = label2.minimumScaleFactor;

NSAttributedString *attributedString2 = [[NSAttributedString alloc] initWithString:label2.text attributes:@{NSFontAttributeName : label2.font}];
[attributedString2 boundingRectWithSize:label2.frame.size options:NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading context:labelContext];

CGFloat actualFontSize2 = label2.font.pointSize * labelContext.actualScaleFactor;

CGFloat minSize = MIN(actualFontSize1, actualFontSize2);

label1.font = [UIFont fontWithName:RCDefaultFontName size:minSize];
label2.font = [UIFont fontWithName:RCDefaultFontName size:minSize];
}

#6

Next code doesn't support minFontSize and lineBreakMode so if you need them you should improve it by yourself:

下一个代码不支持minFontSize和lineBreakMode，所以如果你需要它们，你应该自己改进它：

CGSize NSString_sizeWithFont(NSString * str, UIFont *font) {
    CGSize result;
    if (NO == [str respondsToSelector: @selector(sizeWithAttributes:)]) {
        // legacy way
        result = [str sizeWithFont: font];
    } else {
        // modern way
        NSDictionary * dict = [NSDictionary dictionaryWithObjectsAndKeys:
                               font, NSFontAttributeName, nil];
        result = [str sizeWithAttributes: dict];
    }
    return result;
}

UIFont * NSString_calcActualFont(NSString * str, UIFont * initialFont,
                                 CGSize sizeLimit, CGSize * actualSize)
{
    const CGSize curSize = NSString_sizeWithFont(str, initialFont);

    CGFloat actualFontSize = initialFont.pointSize;
    actualFontSize *= MIN(sizeLimit.width / curSize.width, sizeLimit.height / curSize.height);

    UIFont * actualFont = [initialFont fontWithSize: floorf(actualFontSize)];
    *actualSize = NSString_sizeWithFont(str, actualFont);

    return actualFont;
}

#7

Simple solution for one-line UILabel:

单线UILabel的简单解决方案：

//myLabel - initial label

UILabel *fullSizeLabel = [UILabel new];
fullSizeLabel.font = myLabel.font;
fullSizeLabel.text = myLabel.text;
[fullSizeLabel sizeToFit];

CGFloat actualFontSize = myLabel.font.pointSize * (myLabel.bounds.size.width / fullSizeLabel.bounds.size.width);

//correct, if new font size bigger than initial
actualFontSize = actualFontSize < myLabel.font.pointSize ? actualFontSize : myLabel.font.pointSize;

#8

Erik van der Neut's code worked for me, so I translated it in Swift and wrapped it in a UILabel extension:

Erik van der Neut的代码为我工作，所以我将它翻译成Swift并将其包装在UILabel扩展中：

extension UILabel {

    public func actualFontSize()-> CGFloat {
        let context = NSStringDrawingContext()
        context.minimumScaleFactor = self.minimumScaleFactor

        let attributedString = NSAttributedString(string: self.text ?? "", attributes: [NSFontAttributeName: self.font])
        attributedString.boundingRectWithSize(self.frame.size, options: [.UsesLineFragmentOrigin], context: context)

        return (self.font.pointSize * context.actualScaleFactor)
    }
}