Convert CGImage to NSImage Swift

Question

I am trying to display a CGImage in a NSImageView box and I am having trouble converting the CGImage to a NSImage. How should I approach this situation ? Thank you!

Answer 1

Partially based on Larme's comment:

• for Swift, the NSImage initializer that takes a CGImage is init(cgImage:size:) and a syntax example is:

  let myNsImage = NSImage(cgImage: myCgImage, size: .zero)
  

  .zero is a convenience for using the same size as the CGImage.

• for Objective-C, see Getting NSImage from CGImageRef.

And as a simplified demonstration (! on purpose), this macOS Playground will visually render nsImage identically to the programmatically generated cgImage:

import AppKit
let colorSpace = CGColorSpaceCreateDeviceRGB()
let bitmapInfo = CGBitmapInfo.byteOrder32Big.rawValue | CGImageAlphaInfo.premultipliedLast.rawValue & CGBitmapInfo.alphaInfoMask.rawValue
let s: UInt32 = 0xffbbbbbb, o: UInt32 = 0xff3d85e6, f: UInt32 = 0x00000000
let width = 12; let height = 15
var pixels = [
    f, f, f, f, f, f, f, o, f, f, f, f, f, f, f, f, f, f, f, o, f, f, f, f, f, f, f, f, f, f, f, f, o, f, f, f, f, f, f, o, f, f, f, f, o, f, f, f, f, f, f, f, o, f, f, f, f, o, f, f, f, f, f, f, f, o, f, f, f, o, f, f, f, f, f, f, f, f, o, f, f, f, o, f, f, f, f, f, f, f, f, o, o, f, f, o, f, f, o, o, f, f, f, f, f, o, o, f, f, f, f, f, o, o, o, o, f, f, f, f, s, f, f, f, f, f, f, f, o, o, f, s, s, f, f, f, f, f, f, f, f, f, f, s, s, f, o, o, o, o, o, o, o, o, f, s, s, f, f, f, f, f, f, f, f, f, f, s, s, s, s, s, s, s, s, s, s, s, s, s,
]
var context: CGContext!
pixels.withUnsafeMutableBufferPointer { bufferPointer in
    context = CGContext(data: bufferPointer.baseAddress, width: width, height: height, bitsPerComponent: 8, bytesPerRow: width * 4, space: colorSpace, bitmapInfo: bitmapInfo, releaseCallback: nil, releaseInfo: nil)
}
let cgImage = context.makeImage()!
let nsImage = NSImage(cgImage: cgImage, size: .zero)
_ = nsImage