如何調整打印圖像的大小（swift3）

Question

現在，我的代碼將一個藍色框保存在紅色框中。我需要將藍框的大小縮小50％。因此，所有藍色框都有紅色邊框。我有一個擴展文件應該能夠縮小圖像，但我不知道把它放到我的代碼中。

extension UIImage { 
func resized(withPercentage percentage: CGFloat) -> UIImage? { 
    let canvasSize = CGSize(width: size.width * percentage, height: size.height * percentage) 
    UIGraphicsBeginImageContextWithOptions(canvasSize, false, scale) 
    defer { UIGraphicsEndImageContext() } 
    draw(in: CGRect(origin: .zero, size: canvasSize)) 
    return UIGraphicsGetImageFromCurrentImageContext() 
} 
func resized(toWidth width: CGFloat) -> UIImage? { 
    let canvasSize = CGSize(width: width, height: CGFloat(ceil(width/size.width * size.height))) 
    UIGraphicsBeginImageContextWithOptions(canvasSize, false, scale) 
    defer { UIGraphicsEndImageContext() } 
    draw(in: CGRect(origin: .zero, size: canvasSize)) 
    return UIGraphicsGetImageFromCurrentImageContext() 
}} 

import UIKit 
class ViewController: UIViewController { 

var image1 = UIImage(named: "red") 
var image2 = UIImage(named: "blue") 




    func cropImageIntoQuarterSquare(image: UIImage) -> UIImage? { 
     let originalImageSize: CGSize = image.size 
     let smallImageSize = CGSize(width: (originalImageSize.width + 40), height: (originalImageSize.height + 40)) 


     UIGraphicsBeginImageContext(smallImageSize) 
     image.draw(at: CGPoint.zero) 
     let imageResult = UIGraphicsGetImageFromCurrentImageContext() 
     UIGraphicsEndImageContext() 

     return imageResult 
    } 



override func viewDidLoad() { 
    super.viewDidLoad()} 
    func saveImage(image1: UIImage, image2: UIImage) -> UIImage? { 
     let size1 = image1.size 
     let size2 = image2.size 
     let origin = CGPoint(x: size1.width - size2.width, y: size1.height - size2.height) 

     UIGraphicsBeginImageContext(size1) 
     image1.draw(in: CGRect(origin: CGPoint.zero, size: size1)) 
     image2.draw(in: CGRect(origin: origin, size: size2)) 
     let combinedImage = UIGraphicsGetImageFromCurrentImageContext() 
     UIGraphicsEndImageContext() 

     return combinedImage 
    } 

    func image(_ image: UIImage, didFinishSavingWithError error: Error?, contextInfo: UnsafeRawPointer) { 
     if let error = error { 
      // we got back an error! 
      let ac = UIAlertController(title: "Save error", message: error.localizedDescription, preferredStyle: .alert) 
      ac.addAction(UIAlertAction(title: "OK", style: .default)) 
      present(ac, animated: true) 
     } else { 
      let ac = UIAlertController(title: "Saved!", message: "Your altered image has been saved to your photos.", preferredStyle: .alert) 
      ac.addAction(UIAlertAction(title: "OK", style: .default)) 
      present(ac, animated: true) 
     } 
    } 



@IBAction func d(_ sender: Any) { 


    guard let croppedImage = cropImageIntoQuarterSquare(image: image2!), 
     let combinedImage = saveImage(image1: image1!, image2: croppedImage) else { 
      // handle the error 
      return 
    } 

    UIImageWriteToSavedPhotosAlbum(combinedImage, self, #selector(image(_:didFinishSavingWithError:contextInfo:)), nil) 
    }} 

Answer 1

此功能可以幫助你。您可以根據您的願望編輯尺寸和原始值

func drawImage() -> UIImage { 
    var bottomImage = UIImage(named: "red") 
    //background image 
    let image: UIImage = UIImage(named: "blue") 
    //foreground image 
    let newSize: CGSize = CGSize(width: 80, height: 80) 
    UIGraphicsBeginImageContext(newSize) 

    bottomImage.draw(in: CGRect(x: 0, y: 0, width: newSize.width, height: newSize.height)) 

    image.draw(in: CGRect(x: 20, y: 20, width: 40, height: 40), blendMode: .normal, alpha: 1.0) 
    let newImage: UIImage = UIGraphicsGetImageFromCurrentImageContext()! 
    UIGraphicsEndImageContext() 

    return newImage 
    }