blocks|key|4690394|text|您可以使用sizeWithFont：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4690395|[myString+sizeWithFont:[UIFont+fontWithName:@"HelveticaNeue-Light"+size:24]+++
constrainedToSize:CGSizeMake(293,+10000)]+//+put+the+size+of+your+frame|code-block|syntax|javascript|4690396|但它在iOS+7中已被弃用，因此我建议在UILabel中使用字符串：|4690397|[string+sizeWithAttributes:@{NSFontAttributeName:[UIFont+systemFontOfSize:17.0f]}];|4690398|如果您使用的是rect：|4690399|CGRect+textRect+=+[text+boundingRectWithSize:mySize
+++++++++++++++++++++++++++++++++options:NSStringDrawingUsesLineFragmentOrigin
++++++++++++++++++++++++++++++attributes:@{NSFontAttributeName:FONT}
+++++++++++++++++++++++++++++++++context:nil];

CGSize+size+=+textRect.size;|4690400|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|U|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

You could use sizeWithFont :

<pre><code>[myString sizeWithFont:[UIFont fontWithName:@"HelveticaNeue-Light" size:24] 
constrainedToSize:CGSizeMake(293, 10000)] // put the size of your frame
</code></pre>

But it is deprecated in iOS 7, so I recommend if working with string in UILabel :

<pre><code>[string sizeWithAttributes:@{NSFontAttributeName:[UIFont systemFontOfSize:17.0f]}];
</code></pre>

If you are working with a rect :

<pre><code>CGRect textRect = [text boundingRectWithSize:mySize
 options:NSStringDrawingUsesLineFragmentOrigin
 attributes:@{NSFontAttributeName:FONT}
 context:nil];

CGSize size = textRect.size;
</code></pre>

blocks|key|184597|text|您可以根据Apple's+documentation将UILabel的属性adjustsFontSizeToFitWidth设置为YES|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|184598|entityMap|0|LINK|mutability|MUTABLE|url|https://developer.apple.com/library/ios/documentation/uikit/reference/UILabel_Class/Reference/UILabel.html#//apple_ref/occ/instp/UILabel/adjustsFontSizeToFitWidth^0|R|7|11|P|1T|3|5|L|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@$9|O|A|P|B|C]|$9|Q|A|R|B|C]|$9|S|A|T|B|C]]|D|@$9|U|A|V|1|W]]|E|$]]|$1|F|3|-4|5|6|7|X|8|@]|D|@]|E|$]]]|G|$H|$5|I|J|K|E|$L|M]]]]

You can set the <code>UILabel</code>'s property <code>adjustsFontSizeToFitWidth</code> to <code>YES</code> as per <a href="https://developer.apple.com/library/ios/documentation/uikit/reference/UILabel_Class/Reference/UILabel.html#//apple_ref/occ/instp/UILabel/adjustsFontSizeToFitWidth" rel="nofollow">Apple's documentation</a>

blocks|key|4690478|text|我认为唯一可能的方法是让系统运行大小计算，然后调整大小并重复，直到找到合适的大小。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4690479|即，设置介于特定大小之间的二等分算法。|4690480|例如，运行它的大小为10。太小了。20号，太小了。30码。太大了。25码。太小了。27码。恰到好处，使用27码。|4690481|你甚至可以从几百个开始。|4690482|100号的。太大了。50码。等等。|4690483|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|M|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|N|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|O|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|P|8|@]|9|@]|A|$]]|$1|J|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|K|$]]

The only way I can see this being possible is to have a system that runs the size calculation then adjusts the size and repeats until it finds the right size.

I.e. set up a bisecting algorithm that goes between certain sizes.

i.e. run it for size 10.
Too small.
Size 20.
Too small.
Size 30.
Too big.
Size 25.
Too small.
Size 27.
Just right, use size 27.

You could even start in hundreds.

Size 100.
Too big.
Size 50.
etc...

blocks|key|4690513|text|下面是一段简单的代码，它将计算出适合框架边界的最大字体大小：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4690514|UILabel+*label+=+[[UILabel+alloc]+initWithFrame:frame];
label.text+=+@"Some+text";
float+largestFontSize+=+12;
while+([label.text+sizeWithAttributes:@{NSFontAttributeName:[UIFont+systemFontOfSize:largestFontSize]}].width+>+modifierFrame.size.width)
{
+++++largestFontSize--;
}
label.font+=+[UIFont+systemFontOfSize:largestFontSize];|code-block|syntax|javascript|4690515|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Here is a simple piece of code that will figure out the maximum font size to fit within the bounds of a frame:

<pre><code>UILabel *label = [[UILabel alloc] initWithFrame:frame];
label.text = @"Some text";
float largestFontSize = 12;
while ([label.text sizeWithAttributes:@{NSFontAttributeName:[UIFont systemFontOfSize:largestFontSize]}].width &gt; modifierFrame.size.width)
{
 largestFontSize--;
}
label.font = [UIFont systemFontOfSize:largestFontSize];
</code></pre>

blocks|key|184731|text|这是使用其他答案中的逻辑使动态字体大小随框架宽度变化的代码。while循环可能是危险的，所以请不要犹豫提交改进。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|184732|float+fontSize+=+17.0f;+//initial+font+size
CGSize+rect;
while+(1)+{
+++fontSize+=+fontSize%2B0.1;
+++rect+=+[watermarkText+sizeWithAttributes:@{NSFontAttributeName:[UIFont+systemFontOfSize:fontSize]}];
++++if+((int)rect.width+==+(int)subtitle1Text.frame.size.width)+{
++++++++break;
++++}
}
subtitle1Text.fontSize+=+fontSize;|code-block|syntax|javascript|184733|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

This is the code to have dynamic font size changing by the frame width, using the logic from the other answers. The while loop might be dangerous, so please donot hesitate to submit improvements.

<pre><code>float fontSize = 17.0f; //initial font size
CGSize rect;
while (1) {
 fontSize = fontSize+0.1;
 rect = [watermarkText sizeWithAttributes:@{NSFontAttributeName:[UIFont systemFontOfSize:fontSize]}];
 if ((int)rect.width == (int)subtitle1Text.frame.size.width) {
 break;
 }
}
subtitle1Text.fontSize = fontSize;
</code></pre>

blocks|key|184767|text|更简单/更快(但当然是近似地)的方法是：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|184768|class+func+calculateOptimalFontSize(textLength:CGFloat,+boundingBox:CGRect)+->+CGFloat
++++{
++++++++let+area:CGFloat+=+boundingBox.width+*+boundingBox.height
++++++++return+sqrt(area+/+textLength)
++++}|code-block|syntax|javascript|184769|我们假设每个字符是N+x+N像素，所以我们只计算N+x+N在边界框内的次数。|184770|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Even more easy/faster (but of course approximate) way would be this:

<pre><code>class func calculateOptimalFontSize(textLength:CGFloat, boundingBox:CGRect) -&gt; CGFloat
 {
 let area:CGFloat = boundingBox.width * boundingBox.height
 return sqrt(area / textLength)
 }
</code></pre>

We are assuming each char is N x N pixels, so we just calculate how many times N x N goes inside bounding box.

blocks|key|184814|text|这里有一个使用UITextView对象的方法，似乎可以很好地适用于iOS+9。对于其他应用程序，您可能需要对其进行一些推特。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|184815|/*!
+*+Find+the+height+of+the+smallest+rectangle+that+will+enclose+a+string+using+the+given+font.
+*
+*+@param+string++++++++++++The+string+to+check.
+*+@param+font++++++++++++++The+drawing+font.
+*+@param+width+++++++++++++The+width+of+the+drawing+area.
+*
+*+@return+The+height+of+the+rectngle+enclosing+the+text.
+*/

-+(float)+heightForText:+(NSString+*)+string+font:+(UIFont+*)+font+width:+(float)+width+{
++++NSDictionary+*fontAttributes+=+[NSDictionary+dictionaryWithObject:+font
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++forKey:+NSFontAttributeName];
++++CGRect+rect+=+[string+boundingRectWithSize:+CGSizeMake(width,+INT_MAX)
+++++++++++++++++++++++++++++++++++++++options:+NSStringDrawingUsesLineFragmentOrigin
++++++++++++++++++++++++++++++++++++attributes:+fontAttributes
+++++++++++++++++++++++++++++++++++++++context:+nil];
++++return+rect.size.height;
}

/*!
+*+Find+the+largest+font+size+that+will+allow+a+block+of+text+to+fit+in+a+rectangle+of+the+given+size+using+the+system
+*+font.
+*
+*+The+code+is+tested+and+optimized+for+UITextView+objects.
+*
+*+The+font+size+is+determined+to+±0.5.+Change+delta+in+the+code+to+get+more+or+less+precise+results.
+*
+*+@param+string++++++++++++The+string+to+check.
+*+@param+size++++++++++++++The+size+of+the+bounding+rectangle.
+*
+*+@return:+The+font+size.
+*/

-+(float)+maximumSystemFontSize:+(NSString+*)+string+size:+(CGSize)+size+{
++++//+Hack:+For+UITextView,+the+last+line+is+clipped.+Make+sure+it's+not+one+we+care+about.
++++if+([string+characterAtIndex:+string.length+-+1]+!=+'\n')+{
++++++++string+=+[string+stringByAppendingString:+@"\n"];
++++}
++++string+=+[string+stringByAppendingString:+@"M\n"];

++++float+maxFontSize+=+16.0;
++++float+maxHeight+=+[self+heightForText:+string+font:+[UIFont+systemFontOfSize:+maxFontSize]+width:+size.width];
++++while+(maxHeight+<+size.height)+{
++++++++maxFontSize+*=+2.0;
++++++++maxHeight+=+[self+heightForText:+string+font:+[UIFont+systemFontOfSize:+maxFontSize]+width:+size.width];
++++}

++++float+minFontSize+=+maxFontSize/2.0;
++++float+minHeight+=+[self+heightForText:+string+font:+[UIFont+systemFontOfSize:+minFontSize]+width:+size.width];
++++while+(minHeight+>+size.height)+{
++++++++maxFontSize+=+minFontSize;
++++++++minFontSize+/=+2.0;
++++++++maxHeight+=+minHeight;
++++++++minHeight+=+[self+heightForText:+string+font:+[UIFont+systemFontOfSize:+minFontSize]+width:+size.width];
++++}

++++const+float+delta+=+0.5;
++++while+(maxFontSize+-+minFontSize+>+delta)+{
++++++++float+middleFontSize+=+(minFontSize+%2B+maxFontSize)/2.0;
++++++++float+middleHeight+=+[self+heightForText:+string+font:+[UIFont+systemFontOfSize:+middleFontSize]+width:+size.width];
++++++++if+(middleHeight+<+size.height)+{
++++++++++++minFontSize+=+middleFontSize;
++++++++++++minHeight+=+middleHeight;
++++++++}+else+{
++++++++++++maxFontSize+=+middleFontSize;
++++++++++++maxHeight+=+middleHeight;
++++++++}
++++}

++++return+minFontSize;
}|code-block|syntax|javascript|184816|entityMap^0|7|A|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

Here's a method that seems to work well for iOS 9 using <code>UITextView</code> objects. You might have to tweet it a bit for other applications.

<pre><code>/*!
 * Find the height of the smallest rectangle that will enclose a string using the given font.
 *
 * @param string The string to check.
 * @param font The drawing font.
 * @param width The width of the drawing area.
 *
 * @return The height of the rectngle enclosing the text.
 */

- (float) heightForText: (NSString *) string font: (UIFont *) font width: (float) width {
 NSDictionary *fontAttributes = [NSDictionary dictionaryWithObject: font
 forKey: NSFontAttributeName];
 CGRect rect = [string boundingRectWithSize: CGSizeMake(width, INT_MAX)
 options: NSStringDrawingUsesLineFragmentOrigin
 attributes: fontAttributes
 context: nil];
 return rect.size.height;
}

/*!
 * Find the largest font size that will allow a block of text to fit in a rectangle of the given size using the system
 * font.
 *
 * The code is tested and optimized for UITextView objects.
 *
 * The font size is determined to ±0.5. Change delta in the code to get more or less precise results.
 *
 * @param string The string to check.
 * @param size The size of the bounding rectangle.
 *
 * @return: The font size.
 */

- (float) maximumSystemFontSize: (NSString *) string size: (CGSize) size {
 // Hack: For UITextView, the last line is clipped. Make sure it's not one we care about.
 if ([string characterAtIndex: string.length - 1] != '\n') {
 string = [string stringByAppendingString: @"\n"];
 }
 string = [string stringByAppendingString: @"M\n"];

 float maxFontSize = 16.0;
 float maxHeight = [self heightForText: string font: [UIFont systemFontOfSize: maxFontSize] width: size.width];
 while (maxHeight &lt; size.height) {
 maxFontSize *= 2.0;
 maxHeight = [self heightForText: string font: [UIFont systemFontOfSize: maxFontSize] width: size.width];
 }

 float minFontSize = maxFontSize/2.0;
 float minHeight = [self heightForText: string font: [UIFont systemFontOfSize: minFontSize] width: size.width];
 while (minHeight &gt; size.height) {
 maxFontSize = minFontSize;
 minFontSize /= 2.0;
 maxHeight = minHeight;
 minHeight = [self heightForText: string font: [UIFont systemFontOfSize: minFontSize] width: size.width];
 }

 const float delta = 0.5;
 while (maxFontSize - minFontSize &gt; delta) {
 float middleFontSize = (minFontSize + maxFontSize)/2.0;
 float middleHeight = [self heightForText: string font: [UIFont systemFontOfSize: middleFontSize] width: size.width];
 if (middleHeight &lt; size.height) {
 minFontSize = middleFontSize;
 minHeight = middleHeight;
 } else {
 maxFontSize = middleFontSize;
 maxHeight = middleHeight;
 }
 }

 return minFontSize;
}
</code></pre>

blocks|key|4690684|text|一个小技巧有助于使用sizeWithAttributes:，而不需要迭代以获得正确的结果：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|4690685|NSSize+sampleSize+=+[wordString+sizeWithAttributes:
++++@{+NSFontAttributeName:+[NSFont+fontWithName:fontName+size:fontSize]+}];
CGFloat+ratio+=+rect.size.width+/+sampleSize.width;
fontSize+*=+ratio;|code-block|syntax|javascript|4690686|确保样本的fontSize足够大，以获得良好的结果。|4690687|entityMap^0|A|J|0|0|5|8|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@]|E|$]]|$1|M|3|-4|5|6|7|V|8|@]|D|@]|E|$]]]|N|$]]

A little trick helps to make use of <code>sizeWithAttributes:</code> without the need of iterating for the right result:

<pre><code>NSSize sampleSize = [wordString sizeWithAttributes:
 @{ NSFontAttributeName: [NSFont fontWithName:fontName size:fontSize] }];
CGFloat ratio = rect.size.width / sampleSize.width;
fontSize *= ratio;
</code></pre>

Make sure the <code>fontSize</code> for the sample is big enough to get good results.

blocks|key|4690728|text|下面的代码就可以做到这一点:在一定范围内计算最佳字体大小。此示例位于UITextView子类的上下文中，因此它将其边界用作“给定的帧”：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|4690729|func+binarySearchOptimalFontSize(min:+Int,+max:+Int)+->+Int+{
++++let+middleSize+=+(min+%2B+max)+/+2

++++if+min+>+max+{
++++++++return+middleSize
++++}

++++let+middleFont+=+UIFont(name:+font!.fontName,+size:+CGFloat(middleSize))!

++++let+attributes+=+[NSFontAttributeName+:+middleFont]
++++let+attributedString+=+NSAttributedString(string:+text,+attributes:+attributes)

++++let+size+=+CGSize(width:+bounds.width,+height:+.greatestFiniteMagnitude)
++++let+options:+NSStringDrawingOptions+=+[.usesLineFragmentOrigin,+.usesFontLeading]
++++let+textSize+=+attributedString.boundingRect(with:+size,+options:+options,+context:+nil)

++++if+textSize.size.equalTo(bounds.size)+{
++++++++return+middleSize
++++}+else+if+(textSize.height+>+bounds.size.height+%7C%7C+textSize.width+>+bounds.size.width)+{
++++++++return+binarySearchOptimalFontSize(min:+min,+max:+middleSize+-+1)
++++}+else+{
++++++++return+binarySearchOptimalFontSize(min:+middleSize+%2B+1,+max:+max)
++++}
}|code-block|syntax|javascript|4690730|我希望这能有所帮助。|4690731|entityMap^0|Y|A|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|S|8|@]|D|@]|E|$]]|$1|M|3|-4|5|6|7|T|8|@]|D|@]|E|$]]]|N|$]]

Here is code which will do exactly that: calculate optimal font size within some bounds. This sample is in context of <code>UITextView</code> subclass, so it's using its bounds as a "given frame":

<pre><code>func binarySearchOptimalFontSize(min: Int, max: Int) -&gt; Int {
 let middleSize = (min + max) / 2

 if min &gt; max {
 return middleSize
 }

 let middleFont = UIFont(name: font!.fontName, size: CGFloat(middleSize))!

 let attributes = [NSFontAttributeName : middleFont]
 let attributedString = NSAttributedString(string: text, attributes: attributes)

 let size = CGSize(width: bounds.width, height: .greatestFiniteMagnitude)
 let options: NSStringDrawingOptions = [.usesLineFragmentOrigin, .usesFontLeading]
 let textSize = attributedString.boundingRect(with: size, options: options, context: nil)

 if textSize.size.equalTo(bounds.size) {
 return middleSize
 } else if (textSize.height &gt; bounds.size.height || textSize.width &gt; bounds.size.width) {
 return binarySearchOptimalFontSize(min: min, max: middleSize - 1)
 } else {
 return binarySearchOptimalFontSize(min: middleSize + 1, max: max)
 }
}
</code></pre>

I hope that helps.

blocks|key|184963|text|我喜欢@holtwick给出的方法，但我发现它有时会高估合适的东西。我创建了一个在我的测试中似乎运行良好的调整。提示:别忘了测试像"WWW“甚至"௵௵௵”这样的宽字母。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|184964|func+idealFontSize(for+text:+String,+font:+UIFont,+width:+CGFloat)+->+CGFloat+{
++++let+baseFontSize+=+CGFloat(256)
++++let+textSize+=+text.size(attributes:+[NSFontAttributeName:+font.withSize(baseFontSize)])
++++let+ratio+=+width+/+textSize.width

++++let+ballparkSize+=+baseFontSize+*+ratio
++++let+stoppingSize+=+ballparkSize+/+CGFloat(2)+//+We+don't+want+to+loop+forever,+if+we've+already+come+down+to+50%25+of+the+ballpark+size+give+up
++++var+idealSize+=+ballparkSize
++++while+(idealSize+>+stoppingSize+&&+text.size(attributes:+[NSFontAttributeName:+font.withSize(idealSize)]).width+>+width)+{
++++++++//+We+subtract+0.5+because+sometimes+ballparkSize+is+an+overestimate+of+a+size+that+will+fit
++++++++idealSize+-=+0.5
++++}

++++return+idealSize
}|code-block|syntax|javascript|184965|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

I like the approach given by @holtwick, but found that it would sometimes overestimate what would fit. I created a tweak that seems to work well in my tests. Tip: Don't forget to test with really wide letters like "WWW" or even "௵௵௵"

<pre><code>func idealFontSize(for text: String, font: UIFont, width: CGFloat) -&gt; CGFloat {
 let baseFontSize = CGFloat(256)
 let textSize = text.size(attributes: [NSFontAttributeName: font.withSize(baseFontSize)])
 let ratio = width / textSize.width

 let ballparkSize = baseFontSize * ratio
 let stoppingSize = ballparkSize / CGFloat(2) // We don't want to loop forever, if we've already come down to 50% of the ballpark size give up
 var idealSize = ballparkSize
 while (idealSize &gt; stoppingSize &amp;&amp; text.size(attributes: [NSFontAttributeName: font.withSize(idealSize)]).width &gt; width) {
 // We subtract 0.5 because sometimes ballparkSize is an overestimate of a size that will fit
 idealSize -= 0.5
 }

 return idealSize
}
</code></pre>

blocks|key|4690824|text|以下是我在swift+4中的解决方案：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4690825|private+func+adjustedFontSizeOf(label:+UILabel)+->+CGFloat+{
++++guard+let+textSize+=+label.text?.size(withAttributes:+[.font:+label.font]),+textSize.width+>+label.bounds.width+else+{
++++++++return+label.font.pointSize
++++}

++++let+scale+=+label.bounds.width+/+textSize.width
++++let+actualFontSize+=+scale+*+label.font.pointSize

++++return+actualFontSize
}|code-block|syntax|javascript|4690826|我希望它能帮助一些人。|4690827|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Here is my solution in swift 4:

<pre><code>private func adjustedFontSizeOf(label: UILabel) -&gt; CGFloat {
 guard let textSize = label.text?.size(withAttributes: [.font: label.font]), textSize.width &gt; label.bounds.width else {
 return label.font.pointSize
 }

 let scale = label.bounds.width / textSize.width
 let actualFontSize = scale * label.font.pointSize

 return actualFontSize
}
</code></pre>

I hope it helps someone.

blocks|key|4690851|text|Apple没有提供任何方法来查找适合给定rect中的文本的字体大小。我的想法是在BinarySearch的基础上找到一个最适合给定大小的最佳字体大小。下面的扩展尝试不同的字体大小来收敛到一个完美的字体大小值。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4690852|import+UIKit

extension+UITextView+{
++++@discardableResult+func+adjustFontToFit(_+rect:+CGSize,+minFontSize:+CGFloat+=+5,+maxFontSize:+CGFloat+=+100,+accuracy:+CGFloat+=+0.1)+->+CGFloat+{
++++++++//+To+avoid+text+overflow
++++++++let+targetSize+=+CGSize(width:+floor(rect.width),+height:+rect.height)

++++++++var+minFontSize+=+minFontSize
++++++++var+maxFontSize+=+maxFontSize
++++++++var+fittingSize+=+targetSize

++++++++while+maxFontSize+-+minFontSize+>+accuracy+{
++++++++++++let+midFontSize+=+(minFontSize+%2B+maxFontSize)+/+2
++++++++++++font+=+font?.withSize(midFontSize)
++++++++++++fittingSize+=+sizeThatFits(targetSize)

++++++++++++if+fittingSize.height+<=+rect.height+{
++++++++++++++++minFontSize+=+midFontSize
++++++++++++}+else+{
++++++++++++++++maxFontSize+=+midFontSize
++++++++++++}
++++++++}

++++++++//+It+might+be+possible+that+while+loop+break+with+last+assignment
++++++++//+to+`maxFontSize`,+which+can+overflow+the+available+height
++++++++//+Using+`minFontSize`+will+be+failsafe+
++++++++font+=+font?.withSize(minFontSize)
++++++++return+minFontSize
++++}
}|code-block|syntax|javascript|4690853|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Apple doesn't provides any method to find out a font size which fits the text in a given rect. Idea is to find out an optimal font size which perfectly fits the given size based on BinarySearch. Following extension tries different font sizes to converge to a perfect font size value.
<pre><code>import UIKit

extension UITextView {
 @discardableResult func adjustFontToFit(_ rect: CGSize, minFontSize: CGFloat = 5, maxFontSize: CGFloat = 100, accuracy: CGFloat = 0.1) -&gt; CGFloat {
 // To avoid text overflow
 let targetSize = CGSize(width: floor(rect.width), height: rect.height)

 var minFontSize = minFontSize
 var maxFontSize = maxFontSize
 var fittingSize = targetSize

 while maxFontSize - minFontSize &gt; accuracy {
 let midFontSize = (minFontSize + maxFontSize) / 2
 font = font?.withSize(midFontSize)
 fittingSize = sizeThatFits(targetSize)

 if fittingSize.height &lt;= rect.height {
 minFontSize = midFontSize
 } else {
 maxFontSize = midFontSize
 }
 }

 // It might be possible that while loop break with last assignment
 // to `maxFontSize`, which can overflow the available height
 // Using `minFontSize` will be failsafe 
 font = font?.withSize(minFontSize)
 return minFontSize
 }
}
</code></pre>

I have some text which I am drawing into a fixed frame via an NSAttributedString (code below). At the moment I am hard coding the text size to 16. My question is, is there a way to calculate the best fit size for the text for the given frame ?

<pre><code>- (void)drawText:(CGContextRef)contextP startX:(float)x startY:(float)
y withText:(NSString *)standString
{
 CGContextTranslateCTM(contextP, 0, (bottom-top)*2);
 CGContextScaleCTM(contextP, 1.0, -1.0);

 CGRect frameText = CGRectMake(1, 0, (right-left)*2, (bottom-top)*2);

 NSMutableAttributedString * attrString = [[NSMutableAttributedString alloc] initWithString:standString];
 [attrString addAttribute:NSFontAttributeName
 value:[UIFont fontWithName:@"Helvetica-Bold" size:16.0]
 range:NSMakeRange(0, attrString.length)];

 CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString((__bridge CFAttributedStringRef)(attrString));
 struct CGPath * p = CGPathCreateMutable();
 CGPathAddRect(p, NULL, frameText);
 CTFrameRef frame = CTFramesetterCreateFrame(framesetter, CFRangeMake(0,0), p, NULL);

 CTFrameDraw(frame, contextP);
}
</code></pre>

Calculate Font Size to Fit Frame - Core Text - NSAttributedString - iOS

我有一些文本，我正在绘制成一个固定的框架通过NSAttributedString (代码如下)。目前，我正在将文本大小硬编码为16。我的问题是，对于给定的框架，有没有一种方法可以计算出文本的最佳大小？- (void)drawText:(CGContextRef)contextP startX:(float)x star...

问计算字体大小以适合框架-核心文本- NSAttributedString - iOS
EN

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