xcode Swift - Playground - 核心图形/核心文本/自定义视图
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/27052665/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Swift - Playground - Core Graphics / Core Text / Custom View
提问by Jeef
Question
题
I'm attempting to make a custom UIView component in swift playground. I've been able to figure out how to do everything except for render text correctly. I'm not sure if i'm supposed to do this via Core Graphics or Core Text or exactly how to get it working correctly.
我正在尝试在 swift playground 中制作自定义 UIView 组件。除了正确渲染文本之外，我已经能够弄清楚如何做所有事情。我不确定是否应该通过 Core Graphics 或 Core Text 来执行此操作，或者确切地说是如何使其正常工作。
As you can see in the image below I want to render text both upside down and right side up on either side of my custom View Component
如下图所示，我想在自定义视图组件的任一侧呈现上下颠倒和正面朝上的文本
I've tried various ways to get the text to work but I keep running aground. If somebody would be able to show me how to modify my playground to add a few text rendering that would be awesome.
我尝试了各种方法来让文本正常工作，但我一直搁浅。如果有人能够向我展示如何修改我的操场以添加一些文本渲染，那将是非常棒的。
Playground Code
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
回答by zisoft
I wrote a utility function for my app to draw text using CoreText.
It returns the text size for further processing:
我为我的应用程序编写了一个实用函数来使用CoreText. 它返回文本大小以供进一步处理：
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
}
Call it like so:
像这样称呼它：
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)
Hope that helps you.
希望能帮到你。
