Unable to generate cgImage from UIGraphics

Question

I am developing a game which needs to render tiled pipe form the previously loaded cgImage. For this purpose I am using the following code, however the resized image is not rendered Can someone give me an advice how to fix that?

EDIT: to include minimal code for reproduction `

      import SwiftUI

struct ContentView: View {

@State var reImage : UIImage?

var body: some View {
    VStack {
      
        Image("pipe-green")
            .resizable()
            .scaledToFit()
        Image(uiImage: reImage!)
            .resizable()
            .scaledToFit()
        
        
        Button("Resize") {
            let sizeNew = CGSize(width: 100, height: 300)
            reImage = resizeImage(textures: (pipe: "pipe-green", cap: "bottom-green"), of: sizeNew)
        }

    }
}

func resizeImage(textures: (pipe: String, cap: String), of size: CGSize) -> UIImage? {
    

         guard let texture = UIImage(named: textures.pipe)?.cgImage else {
             return nil
         }
         let textureRect = CGRect(x: 0, y: 0, width: size.width, height: size.height)
 
         // Render tiled pipe form the previously loaded cgImage
         UIGraphicsBeginImageContext(size)
         let context = UIGraphicsGetCurrentContext()
         context?.draw(texture, in: textureRect, byTiling: true)
         let tiledBackground = UIGraphicsGetImageFromCurrentImageContext()
         UIGraphicsEndImageContext()
 

    
   return tiledBackground
}

}

Too many unknowns. Please show sufficient code to allow us to compile your code. For example what is `size`? How do we know it isn't zero? — matt, Aug 17 '22 at 12:51
Also never call `UIGraphicsBeginImageContext`. Use `UIGraphicsBeginImageContextWithOptions` or, far better, use an image renderer. — matt, Aug 17 '22 at 12:55
Thank you @matt I have edited my code. Now you can reproduce the error. — Dakata, Aug 17 '22 at 13:38

score 0 · Answer 1 · answered Aug 17 '22 at 14:41

extension UIImage {
    func resized (to size : CGSize) -> UIImage {
        return UIGraphicsImageRenderer(size: size).image { _ in
            draw(in: CGRect(origin: .zero, size: size))
        }
    }
}

Actually solved it by adding that extension.

Unable to generate cgImage from UIGraphics

1 Answers1