[英]How to draw vertical text in UILabel
我目前正在研究在标签中绘制垂直中文文本。 这是我想要实现的目标,尽管使用汉字:
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。 然而,这感觉非常复杂。 有没有更简单的方法来绘制文本而没有我缺少的复杂 CoreGraphics 魔法?
好吧,你可以这样做:
labelObject.numberOfLines = 0;
labelObject.lineBreakMode = NSLineBreakByCharWrapping;
和 setFrame with -- height:100, width:20 它会正常工作..
有用
UILabel *lbl = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 30, 100)];
lbl.transform = CGAffineTransformMakeRotation((M_PI)/2);
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,并在一条线上放置两个。 例如
W
ai
ti
n
g
我的解决方案是创建一种方法,通过在每个字符后添加\\n
将字符串本身转换为多行文本。 这是方法:
- (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!
如果你想旋转整个标签(包括字符),你可以这样做:
创建标签:
UILabel* label = [[UILabel alloc] initWithFrame:CGRectMake(0.0, 0.0, 300.0, 30.0)]; [label setText:@"Label Text"];
旋转标签:
[label setTransform:CGAffineTransformMakeRotation(-M_PI / 2)];
根据您想如何放置标签,您可能需要设置锚点。 这设置了旋转发生的点。 例如:
[label.layer setAnchorPoint:CGPointMake(0.0, 1.0)];
这是另一种绘制垂直文本的方法,通过UILabel
。 但这与问题想要的有些不同。
@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
示例图像如下:
可以放到storyboard上,直接看结果。 像图像一样,它的框架将包含垂直文本。 文本属性,如textAlignment
、 font
,也能很好地工作。
@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)
}
}
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)
}
}
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
}
}
}
}
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)
}
}
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