如何在UILabel中将文本放入圆圈中
我想将UILabel的文本转换为圆形（而不是rect）。 我用NSLayoutManager ， NSTextContainer和NSTextStorage进行了一些实验，但它似乎不起作用。 以下示例应该将文本流入40×40的较小矩形（标签为120×120），但似乎没有任何影响。
UIFont *font = [UIFont fontWithName:@"HelveticaNeue" size:12]; NSTextStorage *ts = [[NSTextStorage alloc] initWithString:multiline.title attributes:@{NSFontAttributeName:font}]; NSLayoutManager *lm = [[NSLayoutManager alloc] init]; NSTextContainer *tc = [[NSTextContainer alloc] initWithSize:CGSizeMake(40, 40)]; [lm addTextContainer:tc]; [ts addLayoutManager:lm]; self.label.attributedText = ts;
Ides的？
这似乎是一个非常简单的解决方案。 NSTextContainer具有exclusionPaths属性。 您可以做的是创建两个Bezier路径，用于定义应排除的区域。
所以我这样做了，这是我的方法：
- (void)setCircularExclusionPathWithCenter:(CGPoint)center radius:(CGFloat)radius textView:(UITextView *)textView { UIBezierPath *topHalf = [UIBezierPath bezierPath]; [topHalf moveToPoint:CGPointMake(center.x - radius, center.y + radius)]; [topHalf addLineToPoint:CGPointMake(center.x - radius, center.y)]; [topHalf addArcWithCenter:center radius:radius startAngle:M_PI endAngle:0.0f clockwise:NO]; [topHalf addLineToPoint:CGPointMake(center.x + radius, center.y + radius)]; [topHalf closePath]; UIBezierPath *bottomHalf = [UIBezierPath bezierPath]; [bottomHalf moveToPoint:CGPointMake(center.x - radius, center.y - radius)]; [bottomHalf addLineToPoint:CGPointMake(center.x - radius, center.y)]; [bottomHalf addArcWithCenter:center radius:radius startAngle:M_PI endAngle:0 clockwise:YES]; [bottomHalf addLineToPoint:CGPointMake(center.x + radius, center.y - radius)]; [bottomHalf closePath]; textView.textContainer.exclusionPaths = @[bottomHalf, topHalf]; }
用法示例：
[self setCircularExclusionPathWithCenter:CGPointMake(160.0f, 200.0f) radius:100.0f textView:_textView];
我的实验结果如下：
当然你必须使用UITextView而不是UILabel，但我希望它有帮助:)
您无法在UILabel中执行此操作，因为它不允许您访问TextKit堆栈。 我所做的是构建自己的TextKit堆栈和子类NSTextContainer：
-(CGRect)lineFragmentRectForProposedRect:(CGRect)proposedRect atIndex:(NSUInteger)characterIndex writingDirection:(NSWritingDirection)baseWritingDirection remainingRect:(CGRect *)remainingRect { CGRect result = [super lineFragmentRectForProposedRect:proposedRect atIndex:characterIndex writingDirection:baseWritingDirection remainingRect:remainingRect]; CGRect r = CGRectMake(0,0,self.size.width,self.size.height); UIBezierPath* circle = [UIBezierPath bezierPathWithOvalInRect:r]; CGPoint p = result.origin; while (![circle containsPoint:p]) { px += .1; result.origin = p; } CGFloat w = result.size.width; p = result.origin; px += w; while (![circle containsPoint:p]) { w -= .1; result.size.width = w; p = result.origin; px += w; } return result; }
原油但有效。 看起来像这样：
使用Swift 4和iOS 11， NSTextContainer有一个名为exclusionPaths的属性。 exclusionPaths具有以下声明：
一组路径对象，表示文本未显示在文本容器中的区域。
var exclusionPaths: [UIBezierPath] { get set }
此外， UIBezierPath还有一个名为usesEvenOddFillRule的属性。 usesEvenOddFillRule具有以下声明：
一个布尔值，指示偶数奇数绕组规则是否用于绘制路径。
var usesEvenOddFillRule: Bool { get set }
通过使用usesEvenOddFillRule ，您可以创建一个围绕圆圈的排除路径，只需几行代码：
var exclusionPath: UIBezierPath { let path = UIBezierPath(ovalIn: bounds) path.append(UIBezierPath(rect: bounds)) path.usesEvenOddFillRule = true return path }
以下UITextView和UIViewController子类显示如何使用NSTextContainer exclusionPaths和UIBezierPath usesEvenOddFillRule属性在圆圈内显示文本：
TextView.swift
import UIKit class TextView: UITextView { convenience init() { self.init(frame: .zero, textContainer: nil) } override init(frame: CGRect, textContainer: NSTextContainer?) { super.init(frame: frame, textContainer: textContainer) isScrollEnabled = false isEditable = false textContainerInset = .zero self.textContainer.lineBreakMode = .byTruncatingTail } required init?(coder aDecoder: NSCoder) { fatalError("init(coder:) has not been implemented") } var exclusionPath: UIBezierPath { let path = UIBezierPath(ovalIn: bounds) path.append(UIBezierPath(rect: bounds)) path.usesEvenOddFillRule = true return path } }
extension TextView { // Draw circle override func draw(_ rect: CGRect) { UIColor.orange.setFill() let path = UIBezierPath(ovalIn: rect) path.fill() } // Draw exclusion path /* override func draw(_ rect: CGRect) { UIColor.orange.setFill() exclusionPath.fill() } */ }
ViewController.swift
import UIKit class ViewController: UIViewController { let textView = TextView() override func viewDidLoad() { super.viewDidLoad() let string = "Lorem ipsum dolor sit er elit lamet, consectetaur cillium adipisicing pecu, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum. Nam liber te conscient to factor tum poen legum odioque civiuda." textView.attributedText = NSAttributedString(string: string) view.addSubview(textView) textView.translatesAutoresizingMaskIntoConstraints = false let horizontalConstraint = textView.centerXAnchor.constraint(equalTo: view.centerXAnchor) let verticalConstraint = textView.centerYAnchor.constraint(equalTo: view.centerYAnchor) let widthConstraint = textView.widthAnchor.constraint(equalToConstant: 240) let heightConstraint = textView.heightAnchor.constraint(equalToConstant: 240) NSLayoutConstraint.activate([horizontalConstraint, verticalConstraint, widthConstraint, heightConstraint]) } override func viewDidLayoutSubviews() { super.viewDidLayoutSubviews() textView.textContainer.exclusionPaths = [textView.exclusionPath] } }
通过选择draw(_:)一个或另一个实现，您将看到以下显示：
以下是我对Swift 3中上述问题的贡献.https：//github.com/icatmed/ICRoundLabel.git
import UIKit import CoreText @IBDesignable open class ICRoundLabel: UILabel { // Switch on/off text rounding, is on by default @IBInspectable open dynamic var isRounded:Bool = true { didSet{ setNeedsDisplay() } } // Specify text alignment @available(*, unavailable, message: "This property is reserved for Interface Builder. Use 'roundedTextAlignment' instead.") @IBInspectable open dynamic var alignment:UInt8 { set{ self.roundedTextAlignment = CTTextAlignment(rawValue: newValue)! setNeedsDisplay() } get{ return roundedTextAlignment.rawValue } } // Font scale @IBInspectable open dynamic var fillTextInCenter:Bool = true { didSet{ setNeedsDisplay() } } // Font step @available(*, unavailable, message: "This property is reserved for Interface Builder. Use 'internalFontStep' instead.") @IBInspectable open dynamic var fontStep:CGFloat { set(newValue) { internalFontStep = max(newValue, 0.1) } get { return internalFontStep } } open var roundedTextAlignment:CTTextAlignment = .center open var internalFontStep:CGFloat = 1 override open func drawText(in rect: CGRect) { // Check if custom text draw is needed if !isRounded { super.drawText(in: rect) return } // Check if text exists guard let text = self.text else { return } if text == "" { return } // Get graphics context guard let context = UIGraphicsGetCurrentContext() else { return } //MARK: Create attributed string var stringRange = NSMakeRange(0, text.characters.count) let attrString = CFAttributedStringCreate(kCFAllocatorDefault, text as CFString!, attributedText?.attributes(at: 0, effectiveRange: &stringRange) as CFDictionary!) let attributedString = CFAttributedStringCreateMutableCopy(kCFAllocatorDefault, CFIndex.max, attrString)! let stringLength = CFAttributedStringGetLength(attributedString) // Set a paragraph style let cfStringRange = CFRangeMake(0, stringLength) let settings = [CTParagraphStyleSetting(spec: .alignment, valueSize: MemoryLayout.size(ofValue: roundedTextAlignment), value: &roundedTextAlignment)] let paragraphStyle = CTParagraphStyleCreate(settings, 1) CFAttributedStringSetAttribute(attributedString, cfStringRange, kCTParagraphStyleAttributeName, paragraphStyle) // Make custom transitions with context context.translateBy(x: 0.0, y: frame.size.height) context.scaleBy(x: 1.0, y: -1.0) // New drawing rect with insets let drawingRect = CGRect(origin: CGPoint(x: 0, y: 0), size: CGSize(width: rect.size.width, height: rect.size.height)) // Align text in center var boundingBox = text.boundingRect(with: drawingRect.size, options: NSStringDrawingOptions.usesLineFragmentOrigin, attributes: [NSFontAttributeName: font], context: nil) //MARK: Create elliptical path var path = CGPath(roundedRect: drawingRect, cornerWidth: drawingRect.width/2, cornerHeight: drawingRect.height/2, transform: nil) //MARK: Frame and range calculation nested function func getTextFrameRange() -> (CTFrame, CFRange) { let textFrame = CTFramesetterCreateFrame(CTFramesetterCreateWithAttributedString(attributedString), cfStringRange, path, nil) let rangeThatFits = CTFrameGetVisibleStringRange(textFrame) return (textFrame, rangeThatFits) } var textFrame:CTFrame var rangeThatFits:CFRange //MARK: Scaling font size if needed if fillTextInCenter { var fontSize = font.pointSize var estimatedFont = font.withSize(fontSize) // Pin text in center of initial rect var boxHeight = ceil(boundingBox.height) func updateBoundingBox() { boundingBox.origin = CGPoint(x: ceil((drawingRect.size.height - boxHeight)/2), y: ceil((drawingRect.size.height - boxHeight)/2)) boundingBox.size = CGSize(width: boxHeight, height: boxHeight) } path = CGPath(roundedRect: boundingBox, cornerWidth: boundingBox.width/2, cornerHeight: boundingBox.height/2, transform: nil) (_, rangeThatFits) = getTextFrameRange() updateBoundingBox() // Fit text in center while cfStringRange.length != rangeThatFits.length { // Increase size of bounding box size if needed // or decrease font size if boundingBox.width < drawingRect.width { boxHeight += 1 //Update bounding box accoringly to new box size updateBoundingBox() path = CGPath(roundedRect: boundingBox, cornerWidth: boundingBox.width/2, cornerHeight: boundingBox.height/2, transform: nil) (_, rangeThatFits) = getTextFrameRange() continue } else { CFAttributedStringSetAttribute(attributedString, cfStringRange, kCTFontAttributeName, estimatedFont) (_, rangeThatFits) = getTextFrameRange() // Increase or decrease font size fontSize += cfStringRange.length < rangeThatFits.length ? internalFontStep : -internalFontStep estimatedFont = font.withSize(fontSize) } } } //MARK: Draw the text frame in the view's graphics context (textFrame, _) = getTextFrameRange() CTFrameDraw(textFrame, context) } @IBInspectable var borderColor: UIColor = UIColor.white { didSet { layer.borderColor = borderColor.cgColor } } @IBInspectable var borderWidth: CGFloat = 1.0 { didSet { layer.borderWidth = borderWidth } } override open func layoutSubviews() { super.layoutSubviews() layer.cornerRadius = 0.5 * bounds.size.width clipsToBounds = true }
}