CGImage missing ctor to create from NativeHandle/IntPtr

[Cheesebaron]

Steps to Reproduce

In Xamarin.iOS we can do new CGImage(intPtr) this is missing from net6.0-ios. I.e. we have some code generating thumbnails asynchronously:

void ImageReadyCallback(CMTime requestedTime, IntPtr imageRef, CMTime actualTime,
    AVAssetImageGeneratorResult result, NSError imageError)
{
    var image = new CGImage(imageRef);
    var skImage = image.ToSKBitmap();
    t.TrySetResult(skImage);
}

var handler = new AVAssetImageGeneratorCompletionHandler(ImageReadyCallback);

The callback in AVAssetImageGeneratorCompletionHandler still returns IntPtr, but there is no way to get a CGImage from it.

Expected Behavior

Some way to turn the IntPtr back into a CGImage

Actual Behavior

Ctor missing

Environment

Version information

Visual Studio Community 2022 for Mac
Version 17.3.6 (build 20)
Installation UUID: dd331937-eb2e-413a-9850-a08751dab655

Runtime
.NET 6.0.5 (64-bit)
Architecture: Arm64

Roslyn (Language Service)
4.3.0-3.22312.2+52adfb8b2dc71ed4278debcf13960f2116868608

NuGet
Version: 6.2.1.2

.NET SDK (Arm64)
SDK: /usr/local/share/dotnet/sdk/6.0.401/Sdks
SDK Versions:
	6.0.401
	6.0.400
MSBuild SDKs: /Applications/Visual Studio.app/Contents/MonoBundle/MSBuild/Current/bin/Sdks

.NET Runtime (Arm64)
Runtime: /usr/local/share/dotnet/dotnet
Runtime Versions:
	6.0.9
	6.0.8

Xamarin.Profiler
Version: 1.8.0.19
Location: /Applications/Xamarin Profiler.app/Contents/MacOS/Xamarin Profiler

Updater
Version: 11

Xamarin.Android
Version: 13.0.0.0 (Visual Studio Community)
Commit: xamarin-android/d17-3/030cd63
Android SDK: /Users/tomaszcielecki/Library/Developer/Xamarin/android-sdk-macosx
	Supported Android versions:
		12.1 (API level 32)
		12.0 (API level 31)
		10.0 (API level 29)
		13.0 (API level 33)
		7.0  (API level 24)

SDK Command-line Tools Version: 7.0
SDK Platform Tools Version: 33.0.2
SDK Build Tools Version: 33.0.0

Build Information: 
Mono: dffa5ab
Java.Interop: xamarin/java.interop/d17-3@7716ae53
SQLite: xamarin/sqlite/3.38.5@df4deab
Xamarin.Android Tools: xamarin/xamarin-android-tools/main@14076a6

Microsoft Build of OpenJDK
Java SDK: /Library/Java/JavaVirtualMachines/microsoft-11.jdk
11.0.12
Android Designer EPL code available here:
https://github.com/xamarin/AndroidDesigner.EPL

Eclipse Temurin JDK
Java SDK: /Library/Java/JavaVirtualMachines/temurin-8.jdk
1.8.0.302
Android Designer EPL code available here:
https://github.com/xamarin/AndroidDesigner.EPL

Android SDK Manager
Version: 17.3.0.23
Hash: 965bf40
Branch: remotes/origin/d17-3
Build date: 2022-09-22 15.21.49 UTC

Android Device Manager
Version: 0.0.0.1169
Hash: fafb1d5
Branch: fafb1d5
Build date: 2022-09-22 15.21.49 UTC

Apple Developer Tools
Xcode 14.0.1 (21336)
Build 14A400

Xamarin.Mac
Xamarin.Mac not installed. Can't find /Library/Frameworks/Xamarin.Mac.framework/Versions/Current/Version.

Xamarin.iOS
Version: 16.0.0.72 (Visual Studio Community)
Hash: 6756a1146
Branch: release/6.0.4xx-xcode14
Build date: 2022-09-21 08:51:06-0400

Xamarin Designer
Version: 17.3.0.208
Hash: 0de472ea0
Branch: remotes/origin/d17-3
Build date: 2022-09-22 15.21.44 UTC

Build Information
Release ID: 1703060020
Git revision: f7a6334599543f127e737d6de1f362bbe36cebca
Build date: 2022-09-22 15:19:46+00
Build branch: release-17.3
Build lane: release-17.3

Operating System
Mac OS X 12.6.0
Darwin 21.6.0 Darwin Kernel Version 21.6.0
    Mon Aug 22 20:19:52 PDT 2022
    root:xnu-8020.140.49~2/RELEASE_ARM64_T6000 arm64

Installed Workload Ids      Manifest Version      Installation Source
---------------------------------------------------------------------
macos                       12.3.454/6.0.400      SDK 6.0.400
ios                         15.4.454/6.0.400      SDK 6.0.400
maccatalyst                 15.4.454/6.0.400      SDK 6.0.400
maui                        6.0.540/6.0.400       SDK 6.0.400
tvos                        15.4.454/6.0.400      SDK 6.0.400
android                     32.0.465/6.0.400      SDK 6.0.400
android-33                  32.0.465/6.0.400      SDK 6.0.400

Build Logs

Example Project (If Possible)

[rolfbjarne]

Try doing this:

using ObjCRuntime;

var image = Runtime.GetINativeObject<CGImage> (imageRef, false);

does that work for you?

[ghost]

Hi @Cheesebaron. We have added the "need-info" label to this issue, which indicates that we have an open question for you before we can take further action. This issue will be closed automatically in 7 days if we do not hear back from you by then - please feel free to re-open it if you come back to this issue after that time.

[Cheesebaron]

@rolfbjarne yep, that seems to work.

[chamons]

That is the supported path forward, as the IntPtr constructors are no longer public.

Thanks for the feedback.

[rolfbjarne]

I'm adding an overload that takes a callback that will be given the CGImage instance (instead of the handle): #16325.