image example

imageexample.swift

import CoreText
import UIKit

class ImageFactory {
    
    class func image(size:CGSize)->CGImage?{
        
        let colorSpace = CGColorSpaceCreateDeviceRGB()
        guard let ctx = CGContext(data: nil,
                                  width: Int(size.width),
                                  height: Int(size.height),
                                  bitsPerComponent: 8,
                                  bytesPerRow: 8*(Int(size.width)),
                                  space: colorSpace,
                                  bitmapInfo: CGImageAlphaInfo.premultipliedLast.rawValue) else {
                                    print("no context")
                                    return nil
        }
        
        ctx.setFillColor(UIColor.orange.cgColor)
        
        let fillRect = CGRect(x: 0, y: 0, width: size.width, height: size.height)
        ctx.fill(fillRect)
        
        ctx.setBlendMode(.clear)
        
        let para = NSMutableParagraphStyle()
        para.alignment = .center
        
        let fontSize = floor(size.width*0.8)
        let font = UIFont.boldSystemFont(ofSize: fontSize)
//        let font = UIFont(name: "GillSans", size: fontSize)!
//        let font = UIFont(name: "Kailasa", size: fontSize)!
        
        let attrString = NSAttributedString(string: "L",
                                            attributes:  [
                                                .font:font,
                                                .paragraphStyle:para
            ])
        
        let framesetter = CTFramesetterCreateWithAttributedString(attrString as CFAttributedString)
        let stringRange = CFRangeMake(0, attrString.length)
        let suggestedSize = CTFramesetterSuggestFrameSizeWithConstraints(framesetter, stringRange, nil, fillRect.size, nil)
        let safeSize = CGSize(width: ceil(suggestedSize.width), height: ceil(suggestedSize.height))
        
        print(suggestedSize)
        print(safeSize)
        
        let path = CGMutablePath()
        path.addRect(CGRect(origin: CGPoint(x: 6, y: 6), size: safeSize))
        
        let frame = CTFramesetterCreateFrame(framesetter, stringRange, path, nil)
        print(frame)
        
        let framePath = CTFrameGetPath(frame)
        print(framePath)
        
        CTFrameDraw(frame, ctx)
        
        let cgImage = ctx.makeImage()
        
        return cgImage
    }
}

let i = ImageFactory.image(size: CGSize(width: 150, height: 150))