UIGraphicsBeginImageContext vs UIGraphicsImageRenderer ​

UIGraphicsBeginImageContextWithOptions has been deprecated from iOS17, and it will crash on iOS17 when the height or width of size argument is 0.

We should replace UIGraphicsBeginImageContextWithOptions with UIGraphicsImageRenderer.

Render an image with UIGraphicsBeginImageContext ​

let bound = CGRect(x: 0, y: 0, width: 200, height: 200)
UIGraphicsBeginImageContextWithOptions(bound.size, false, UIScreen.main.scale)
if let context = UIGraphicsGetCurrentContext() {
    UIColor.darkGray.setStroke()
    context.stroke(bound)
    UIColor(red: 158/255, green: 215/255, blue: 245/255, alpha: 1).setFill()
    context.fill(CGRect(x: 1, y: 1, width: 140, height: 140))
    let image = UIGraphicsGetImageFromCurrentImageContext()
}
UIGraphicsEndImageContext()

let bound = CGRect(x: 0, y: 0, width: 200, height: 200)
UIGraphicsBeginImageContextWithOptions(bound.size, false, UIScreen.main.scale)
if let context = UIGraphicsGetCurrentContext() {
    UIColor.darkGray.setStroke()
    context.stroke(bound)
    UIColor(red: 158/255, green: 215/255, blue: 245/255, alpha: 1).setFill()
    context.fill(CGRect(x: 1, y: 1, width: 140, height: 140))
    let image = UIGraphicsGetImageFromCurrentImageContext()
}
UIGraphicsEndImageContext()

The above code creates the following image:

Render an image with UIGraphicsImageRenderer ​

Rendering the same image with UIGraphicsImageRenderer.

1. [Optional] Create a UIGraphicsImageRendererFormat object and specify render parameters.

let format = UIGraphicsImageRendererFormat.default()
format.opaque = true

let format = UIGraphicsImageRendererFormat.default()
format.opaque = true

2. Create a UIGraphicsImageRenderer object, providing size arugment and format argument(optional).
   
   If you don't provider format object, the render uses default format for the current device.

let renderer = UIGraphicsImageRenderer(size: CGSize(width: 200, height: 200))

let renderer = UIGraphicsImageRenderer(size: CGSize(width: 200, height: 200))

let format = UIGraphicsImageRendererFormat.default()
format.opaque = false
let renderer = UIGraphicsImageRenderer(size: CGSize(width: 200, height: 200),format: format)

let format = UIGraphicsImageRendererFormat.default()
format.opaque = false
let renderer = UIGraphicsImageRenderer(size: CGSize(width: 200, height: 200),format: format)

3. Call one of the three rendering methods and provide Core Graphics drawing instructions as the closure argument to execute the rendering.

   • image(actions:) return a UIImage object.
   swift

   let renderer = UIGraphicsImageRenderer(size: CGSize(width: 200, height: 200))
   let image = renderer.image { (context) in
       UIColor.darkGray.setStroke()
       context.stroke(renderer.format.bounds)
       UIColor(red: 158/255, green: 215/255, blue: 245/255, alpha: 1).setFill()
       context.fill(CGRect(x: 1, y: 1, width: 140, height: 140))
   }

   let renderer = UIGraphicsImageRenderer(size: CGSize(width: 200, height: 200))
   let image = renderer.image { (context) in
       UIColor.darkGray.setStroke()
       context.stroke(renderer.format.bounds)
       UIColor(red: 158/255, green: 215/255, blue: 245/255, alpha: 1).setFill()
       context.fill(CGRect(x: 1, y: 1, width: 140, height: 140))
   }

   • jpegData(withCompressionQuality:actions:) returns a JPEG-encoded Data object.
   swift

   let renderer = UIGraphicsImageRenderer(size: CGSize(width: 200, height: 200))
   let jpegData = renderer.jpegData(withCompressionQuality: 0.8) { context in
       UIColor.darkGray.setStroke()
       context.stroke(renderer.format.bounds)
       UIColor(red: 158/255, green: 215/255, blue: 245/255, alpha: 1).setFill()
       context.fill(CGRect(x: 1, y: 1, width: 140, height: 140))
   }
   let image = UIImage(data: jpegData)

   let renderer = UIGraphicsImageRenderer(size: CGSize(width: 200, height: 200))
   let jpegData = renderer.jpegData(withCompressionQuality: 0.8) { context in
       UIColor.darkGray.setStroke()
       context.stroke(renderer.format.bounds)
       UIColor(red: 158/255, green: 215/255, blue: 245/255, alpha: 1).setFill()
       context.fill(CGRect(x: 1, y: 1, width: 140, height: 140))
   }
   let image = UIImage(data: jpegData)

   • pngData(actions:) returns a PNG-encoded Data object.
   swift

   let renderer = UIGraphicsImageRenderer(size: CGSize(width: 200, height: 200))
   let pngData = renderer.pngData { context in
       UIColor.darkGray.setStroke()
       context.stroke(renderer.format.bounds)
       UIColor(red: 158/255, green: 215/255, blue: 245/255, alpha: 1).setFill()
       context.fill(CGRect(x: 1, y: 1, width: 140, height: 140))
   }
   let image = UIImage(data: pngData)

   let renderer = UIGraphicsImageRenderer(size: CGSize(width: 200, height: 200))
   let pngData = renderer.pngData { context in
       UIColor.darkGray.setStroke()
       context.stroke(renderer.format.bounds)
       UIColor(red: 158/255, green: 215/255, blue: 245/255, alpha: 1).setFill()
       context.fill(CGRect(x: 1, y: 1, width: 140, height: 140))
   }
   let image = UIImage(data: pngData)

References ​

• UIGraphicsBeginImageContext Deprecated #984
• Drawing into a Core Graphics context with UIGraphicsImageRenderer