Legacy UIGraphics Function

Prefer using UIGraphicsImageRenderer over legacy functions

• Identifier: legacy_uigraphics_function
• Enabled by default: No
• Supports autocorrection: No
• Kind: idiomatic
• Analyzer rule: No
• Minimum Swift compiler version: 5.0.0
• Default configuration:

  Key	Value
  severity	warning

Rationale

The modern replacement is safer, cleaner, Retina-aware and more performant.

Non Triggering Examples

let renderer = UIGraphicsImageRenderer(size: bounds.size)
let screenshot = renderer.image { _ in
    myUIView.drawHierarchy(in: bounds, afterScreenUpdates: true)
}

let renderer = UIGraphicsImageRenderer(size: newSize)
let combined = renderer.image { _ in
    background.draw(in: CGRect(origin: .zero, size: newSize))
    watermark.draw(in: CGRect(origin: .zero, size: watermarkSize))
}

UIGraphicsImageRenderer(size: newSize, format: UIGraphicsImageRendererFormat()).image { _ in
    image.draw(in: CGRect(origin: .zero, size: newSize))
}

Triggering Examples

↓UIGraphicsBeginImageContext(newSize)
myUIView.drawHierarchy(in: bounds, afterScreenUpdates: false)
let optionalScreenshot = ↓UIGraphicsGetImageFromCurrentImageContext()
↓UIGraphicsEndImageContext()

↓UIGraphicsBeginImageContext(newSize)
background.draw(in: CGRect(origin: .zero, size: newSize))
watermark.draw(in: CGRect(origin: .zero, size: watermarkSize))
let optionalOutput = ↓UIGraphicsGetImageFromCurrentImageContext()
↓UIGraphicsEndImageContext()

↓UIGraphicsBeginImageContextWithOptions(newSize, true, 1.0)
image.draw(in: CGRect(origin: .zero, size: newSize))
let optionalOutput = ↓UIGraphicsGetImageFromCurrentImageContext()
↓UIGraphicsEndImageContext()