Swift – Playground – 核心graphics/核心文本/自定义视图

题

我试图在swift操场上制作一个自定义的UIView组件。 我已经能够弄清楚除了正确渲染文本之外，如何做所有事情。 我不知道如果我应该通过核心graphics或核心文本，或如何让它正常工作。

正如你在下面的图片中看到的，我想在我的自定义视图组件的任一侧上颠倒和右侧渲染文本

我已经尝试了各种方式来让文本工作，但我一直搁浅。 如果有人能够告诉我如何修改我的游乐场，以添加几个文本渲染将是非常棒的。

游乐场代码

// Playground - noun: a place where people can play import Foundation import UIKit class RunwayView : UIView { var northText : String? var southText : String? ///Draws the "runway" override func drawRect(rect: CGRect) { // Setup graphics context var ctx = UIGraphicsGetCurrentContext() // clear context CGContextClearRect(ctx, rect) let parentVieBounds = self.bounds let width = CGRectGetWidth(parentVieBounds) let height = CGRectGetHeight(parentVieBounds) // Setup the heights let endZoneHeight : CGFloat = 40 /* Remember y is negative and 0,0 is upper left*/ //Create EndZones CGContextSetRGBFillColor(ctx, 0.8, 0.8, 0.8, 1) CGContextFillRect(ctx, CGRectMake(0, 0, width, endZoneHeight)) CGContextFillRect(ctx, CGRectMake(0, height-endZoneHeight, width, endZoneHeight)) var northString = NSMutableAttributedString(string: "36") var attrs = [NSFontAttributeName : UIFont.systemFontOfSize(16.0)] var gString = NSMutableAttributedString(string:"g", attributes:attrs); var line = CTLineCreateWithAttributedString(gString) CGContextSetTextPosition(ctx, 10, 50); CTLineDraw(line, ctx); // Clean up } } var outerFrame : UIView = UIView(frame: CGRectMake(20,20,400,400)) var runway1 : RunwayView = RunwayView(frame: CGRectMake(0,0,30,260)) var runway2 : RunwayView = RunwayView(frame: CGRectMake(80,0,30,340)) runway1.transform = CGAffineTransformConcat(CGAffineTransformMakeTranslation(20, 200), CGAffineTransformMakeRotation(-0.785398163)) outerFrame.addSubview(runway1) runway2.transform = CGAffineTransformConcat(CGAffineTransformMakeTranslation(120, 140), CGAffineTransformMakeRotation(-0.585398163)) outerFrame.addSubview(runway2) outerFrame.backgroundColor = UIColor.yellowColor() outerFrame.clipsToBounds = true // View these elements runway1 outerFrame runway1 

Answer 1

我为我的应用程序编写了一个实用程序function，使用CoreText绘制文本。 它返回进一步处理的文本大小：

 func drawText(context: CGContextRef, text: NSString, attributes: [String: AnyObject], x: CGFloat, y: CGFloat) -> CGSize { let font = attributes[NSFontAttributeName] as UIFont let attributedString = NSAttributedString(string: text, attributes: attributes) let textSize = text.sizeWithAttributes(attributes) // y: Add font.descender (its a negative value) to align the text at the baseline let textPath = CGPathCreateWithRect(CGRect(x: x, y: y + font.descender, width: ceil(textSize.width), height: ceil(textSize.height)), nil) let frameSetter = CTFramesetterCreateWithAttributedString(attributedString) let frame = CTFramesetterCreateFrame(frameSetter, CFRange(location: 0, length: attributedString.length), textPath, nil) CTFrameDraw(frame, context) return textSize } 

像这样调用它：

 var textAttributes: [String: AnyObject] = [ NSForegroundColorAttributeName : UIColor(white: 1.0, alpha: 1.0).CGColor, NSFontAttributeName : UIFont.systemFontOfSize(17) ] drawText(ctx, text: "Hello, World!", attributes: textAttributes, x: 50, y: 50) 

希望能帮助你。