Warning-free bindings for the legacy CoreGraphics screenshot/window-capture functions.

UnsafeCGWindowListCreateImage.swift

//
//  UnsafeCGWindowListCreateImage.swift
//
//  Created by Stephan Casas on 3/10/25.
//

import Foundation
import CoreGraphics

func UnsafeCGWindowListCreateImage(
  screenBounds: CGRect = .infinite,
  listOption: CGWindowListOption = .optionAll,
  windowNumber: CGWindowID = kCGNullWindowID,
  imageOption: CGWindowImageOption = .bestResolution
) -> CGImage? {
  guard
    let CoreGraphicsFramework = dlopen(
      "/System/Library/Frameworks/CoreGraphics.framework/CoreGraphics", RTLD_NOW),
    let _CGWindowListCreateImage = dlsym(
      CoreGraphicsFramework, "CGWindowListCreateImage")
  else {
    fatalError("Could not load pointer for symbol: CGWindowListCreateImage")
  }

  return unsafeBitCast(
    _CGWindowListCreateImage,
    to: (@convention(c) (
      _ screenBounds: CGRect,
      _ listOption: CGWindowListOption,
      _ windowNumber: CGWindowID,
      _ imageOption: CGWindowImageOption
    ) -> CGImage?).self)(screenBounds, listOption, windowNumber, imageOption)
}

func UnsafeCGWindowListCreateImageFromArray(
  screenBounds: CGRect = .infinite,
  windowArray: [CGWindowID],
  imageOption: CGWindowImageOption = .bestResolution
) -> CGImage? {
  guard
    let SkyLightFramework = dlopen(
      "/System/Library/PrivateFrameworks/SkyLight.framework/SkyLight", RTLD_NOW),
    let _SLWindowListCreateImageFromArray = dlsym(
      SkyLightFramework, "SLWindowListCreateImageFromArray")
  else {
    fatalError("Could not load pointer for symbol: CGWindowListCreateImageFromArray")
  }

  let ptrList = UnsafeMutablePointer<UnsafeRawPointer?>.allocate(
    capacity: windowArray.count)
  windowArray.enumerated().forEach({
    ptrList[$0] = .init(bitPattern: UInt($1))
  })

  guard let cfArray = CFArrayCreate(
    kCFAllocatorDefault, ptrList, windowArray.count, nil
  ) else {
    return nil
  }

  return unsafeBitCast(
    _SLWindowListCreateImageFromArray,
    to: (@convention(c) (
      _ screenBounds: CGRect,
      _ windowArray: CFArray,
      _ imageOption: CGWindowImageOption
    ) -> CGImage?).self)(screenBounds, cfArray, imageOption)
}