Question

我有一个CATextlayer的特定大小和NSAttributedString未知长度的文字。

我需要调整字体大小，以便文本适合框架（反之亦然：）

任何想法从哪里开始？：）

[编辑]正如nall指出的那样，我可以确定字符串长度，当然，这是用户输入的一些文本，我需要将其放入一个固定大小的框中。

Answer 1

我通过这样做实现了它：

    float fontSize = InitialFontSize;
    UIFont *myFont = [UIFont boldSystemFontOfSize:fontSize];
    CGSize myFontSize = [YourTextHere sizeWithFont:myFont];
    while (myFontSize.width >= MaximunWidth) {
        fontSize -= 0.1f;
        myFont = [UIFont boldSystemFontOfSize:fontSize];
        myFontSize = [YourTextHere sizeWithFont:myFont];
    }
    CATextLayer *textLayer = [CATextLayer layer];
    [textLayer setFrame:CGRectMake(MaximunWidth - myFontSize.width / 2, MaximunHeight - myFontSize.height / 2, myFontSize.width, myFontSize.height)];
    [textLayer setFontSize:fontSize];
    [textLayer setString:YourTextHere];

    [textLayer setAlignmentMode:kCAAlignmentCenter];

Answer 2

我最终这样做了：

textlayer是CATextlayer

theString是NSMutableAttributedString

是的，它不是很优雅，绝对可以改进;）

CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString((__bridge CFAttributedStringRef)theString);

    CGRect columnRect = CGRectMake(0, 0 , 320, 150);

    CGMutablePathRef path = CGPathCreateMutable();
    CGPathAddRect(path, NULL, columnRect);

    CTFrameRef frame = CTFramesetterCreateFrame(framesetter, CFRangeMake(0, 0), path, NULL);

    CFRange frameRange = CTFrameGetVisibleStringRange(frame); 

    int fontSize = 18;

    while(theString.string.length > frameRange.length){

        fontSize--;

        CFStringRef fontName = (__bridge CFStringRef)[defs objectForKey:@"font"];

        CTFontRef font = CTFontCreateWithName(fontName, fontSize, NULL);

        [theString addAttribute:(NSString *)kCTFontAttributeName
                          value:(__bridge id)font
                          range:NSMakeRange(0, theString.string.length)];

        CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString((__bridge CFAttributedStringRef)theString);

        CGRect columnRect = CGRectMake(0, 0 , 320, 150);

        CGMutablePathRef path = CGPathCreateMutable();
        CGPathAddRect(path, NULL, columnRect);

        CTFrameRef frame = CTFramesetterCreateFrame(framesetter, CFRangeMake(0, 0), path, NULL);

        frameRange = CTFrameGetVisibleStringRange(frame); 

        textLayer.string = theString;
    }

Answer 3

我相信你问的问题与this question相同。

看起来您必须迭代各种字体大小以确定哪种字体适合您的矩形。

Answer 4

为 Swift 5 干净解决方案工作。

1）扩展字符串

extension String {
    func size(OfFont font: UIFont) -> CGSize {
        return (self as NSString).size(withAttributes: [NSAttributedString.Key.font: font])
    }
}

2）子类化CATextLayer

class DynamicTextLayer : CATextLayer {
    var adjustsFontSizeToFitWidth = false

    override func layoutSublayers() {
        super.layoutSublayers()
        if adjustsFontSizeToFitWidth {
            fitToFrame()
        }
    }

    func fitToFrame(){
        // Calculates the string size.
        var stringSize: CGSize  {
            get { return (string as? String)!.size(OfFont: UIFont(name: (font as! UIFont).fontName, size: fontSize)!) }
        }
        // Adds inset from the borders. Optional
        let inset: CGFloat = 2
        // Decreases the font size until criteria met
        while frame.width < stringSize.width + inset {
            fontSize -= 1
        }
    }
}

3）现在转到您的代码，使用DynamicTextLayer代替CATextLayer

textLayer = DynamicTextLayer()
textLayer?.alignmentMode = .center
textLayer?.fontSize = 40
textLayer?.string = "Example"
textLayer?.adjustsFontSizeToFitWidth = true

Answer 5

CATextLayer *textLayer;

[textLayer setWrapped: TRUE];

希望这将有效

CATextlayer改变FONT的大小以适合帧

5 个答案: