如何在 UILabel 中绘制垂直文本

Question

我目前正致力于在标签中绘制竖排中文文本。这是我想要实现的目标，尽管是中文字符：

我一直在计划绘制每个字符，将每个字符向左旋转 90 度，然后通过仿射变换旋转整个标签以获得最终结果。但是，感觉非常复杂。有没有一种更简单的方法来绘制文本而没有我所缺少的复杂的 CoreGraphics 魔法？

Answer 1

好吧，你可以这样做：

labelObject.numberOfLines = 0;
labelObject.lineBreakMode = NSLineBreakByCharWrapping;

和 setFrame 与 --height:100, width:20 它会正常工作..

Answer 2

有效

UILabel *lbl = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 30, 100)];
lbl.transform = CGAffineTransformMakeRotation((M_PI)/2);

Answer 3

尝试了 Simha.IC 提供的方法，但对我来说效果不佳。有些字符比其他字符更薄，并被放置在一条线上。例如

W
ai
ti
n
g

我的解决方案是创建一个方法，通过在每个字符后添加\n 将字符串本身转换为多行文本。方法如下：

- (NSString *)transformStringToVertical:(NSString *)originalString
{
    NSMutableString *mutableString = [NSMutableString stringWithString:originalString];
    NSRange stringRange = [mutableString rangeOfString:mutableString];

    for (int i = 1; i < stringRange.length*2 - 2; i+=2)
    {
        [mutableString insertString:@"\n" atIndex:i];
    }

    return mutableString;
}

然后你只需像这样设置标签：

label.text = [self transformStringToVertical:myString];
CGRect labelFrame = label.frame;
labelFrame.size.width  = label.font.pointSize;
labelFrame.size.height = label.font.lineHeight * myString.length;
label.frame = labelFrame;

享受吧！

Answer 4

如果你想旋转整个标签（包括字符），你可以这样做：

1. 首先将 QuartzCore 库添加到您的项目中。

2. 创建标签：

   UILabel* label = [[UILabel alloc] initWithFrame:CGRectMake(0.0, 0.0, 300.0, 30.0)];
   [label setText:@"Label Text"];
   

3. 旋转标签：

   [label setTransform:CGAffineTransformMakeRotation(-M_PI / 2)];
   

根据您希望如何放置标签，您可能需要设置锚点。这设置了发生旋转的点。例如：

    [label.layer setAnchorPoint:CGPointMake(0.0, 1.0)];

Answer 5

这是绘制垂直文本的另一种方法，通过子类化UILabel。但这与问题想要的有所不同。

目标-C

@implementation MyVerticalLabel

// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect {
    // Drawing code

    CGContextRef context = UIGraphicsGetCurrentContext();

    CGAffineTransform transform = CGAffineTransformMakeRotation(-M_PI_2);
    CGContextConcatCTM(context, transform);
    CGContextTranslateCTM(context, -rect.size.height, 0);

    CGRect newRect = CGRectApplyAffineTransform(rect, transform);
    newRect.origin = CGPointZero;

    NSMutableParagraphStyle *textStyle = [[NSMutableParagraphStyle defaultParagraphStyle] mutableCopy];
    textStyle.lineBreakMode = self.lineBreakMode;
    textStyle.alignment = self.textAlignment;

    NSDictionary *attributeDict =
    @{
      NSFontAttributeName : self.font,
      NSForegroundColorAttributeName : self.textColor,
      NSParagraphStyleAttributeName : textStyle,
      };
    [self.text drawInRect:newRect withAttributes:attributeDict];
}
@end

示例图片如下：

斯威夫特

它可以放在故事板上，直接观看结果。像图像一样，它的框架将包含垂直文本。文本属性，如textAlignment、font，也很有效。

@IBDesignable
class MyVerticalLabel: UILabel {

    override func drawRect(rect: CGRect) {
        guard let text = self.text else {
            return
        }

        // Drawing code
        let context = UIGraphicsGetCurrentContext()

        let transform = CGAffineTransformMakeRotation( CGFloat(-M_PI_2))
        CGContextConcatCTM(context, transform)
        CGContextTranslateCTM(context, -rect.size.height, 0)

        var newRect = CGRectApplyAffineTransform(rect, transform)
        newRect.origin = CGPointZero

        let textStyle = NSMutableParagraphStyle.defaultParagraphStyle().mutableCopy() as! NSMutableParagraphStyle
        textStyle.lineBreakMode = self.lineBreakMode
        textStyle.alignment = self.textAlignment

        let attributeDict: [String:AnyObject] = [
            NSFontAttributeName: self.font,
            NSForegroundColorAttributeName: self.textColor,
            NSParagraphStyleAttributeName: textStyle,
        ]

        let nsStr = text as NSString
        nsStr.drawInRect(newRect, withAttributes: attributeDict)
    }

}

斯威夫特 4

override func draw(_ rect: CGRect) {
    guard let text = self.text else {
        return
    }

    // Drawing code
    if let context = UIGraphicsGetCurrentContext() {
        let transform = CGAffineTransform( rotationAngle: CGFloat(-Double.pi/2))
        context.concatenate(transform)
        context.translateBy(x: -rect.size.height, y: 0)
        var newRect = rect.applying(transform)
        newRect.origin = CGPoint.zero

        let textStyle = NSMutableParagraphStyle.default.mutableCopy() as! NSMutableParagraphStyle
        textStyle.lineBreakMode = self.lineBreakMode
        textStyle.alignment = self.textAlignment

        let attributeDict: [NSAttributedStringKey: AnyObject] = [NSAttributedStringKey.font: self.font, NSAttributedStringKey.foregroundColor: self.textColor, NSAttributedStringKey.paragraphStyle: textStyle]

        let nsStr = text as NSString
        nsStr.draw(in: newRect, withAttributes: attributeDict)
    }
}

Answer 6

斯威夫特 5

使用 CGAffineTransform 更简单的方法

import UIKit
class ViewController: UIViewController {

@IBOutlet weak var verticalText: UILabel

    override func viewDidLoad() {

        verticalText.transform = CGAffineTransform(rotationAngle:CGFloat.pi/2)
    }
}

Answer 7

import UIKit

class VerticalLabel : UILabel {
    
    private var _text : String? = nil
    
    override var text : String? {
        get {
            return _text
        }
        set {
            self.numberOfLines = 0
            self.textAlignment = .center
            self.lineBreakMode = .byWordWrapping
            _text = newValue
            if let t = _text {
                var s = ""
                for c in t {
                    s += "\(c)\n"
                }
                super.text = s
            }
        }
    }
    
}