SkiaSharp: NullReferenceException in System.Delegate.Combine on macOS in 1.68.0

I believe I fixed the issue by not assuming what my samples are, but rather asking the system. I updated the way surface are created in ALL the views as well, just to prevent any future issue on other platforms. https://github.com/mono/SkiaSharp/pull/741

OK, I think I know what to do now. I can query the context for the supported sample count. In the meantime, you can use SKCanvasView or the custom view.

I am going to improve the views a bit since they haven’t really been touched since the beginning. I need to add colorspace support as well, see #732

All right, I have found the issue. It appears that on my old MacBook, I can only have a surface with 1 sample. And, on my new MacBook, I can have 8. In both cases, I requested 4, but appears that I only got 1 on one machine and 8 on another.

I need to investigate this some more, but I can implement a fix for the time being - I can just query SkiaSharp for the number of samples that it is allowed.

In the meantime, you can see what your machine outputs but running this modified app:

Source: Modified.zip App: SkiaSharpMacTest.app.zip

Let me know what you get on your side before I make any changes…

One last thing to check is to send me your .app file and I can run it here to confirm that it is your system - it might be just the tooling used to build the package is bad and affecting the running. I have also contacted our resident mac experts to get some real advice.

The only thing that I can see as a difference is the OS:

ME Mac OS X 10.13.6 Darwin 17.7.0 Darwin Kernel Version 17.7.0 Fri Nov 2 20:43:16 PDT 2018 root:xnu-4570.71.17~1/RELEASE_X86_64 x86_64

YOU Mac OS X 10.14.2 Darwin 18.2.0 Darwin Kernel Version 18.2.0 Mon Nov 12 20:24:46 PST 2018 root:xnu-4903.231.4~2/RELEASE_X86_64 x86_64

It appears my mac did not actually let me know there was a major update 😭 I’ll update and see what happens.

clearing the nuget cache or deleting the skiasharp packages manually didn’t solve the problem. I will run the code on a second mac tomorrow. Here are the details from VS > About

=== Visual Studio Professional 2017 for Mac ===

Version 7.7.2 (build 21)
Installation UUID: 606b8730-5344-4f22-8895-9af524c45723
	GTK+ 2.24.23 (Raleigh theme)
	Xamarin.Mac 4.4.1.178 (master / eeaeb7e6)

	Package version: 516000221

=== Mono Framework MDK ===

Runtime:
	Mono 5.16.0.221 (2018-06/b63e5378e38) (64-bit)
	Package version: 516000221

=== NuGet ===

Version: 4.8.0.5385

=== .NET Core ===

Runtime: /usr/local/share/dotnet/dotnet
Runtime Versions:
	2.2.0
	2.1.5
	2.1.2
SDK: /usr/local/share/dotnet/sdk/2.2.100/Sdks
SDK Versions:
	2.2.100
	2.1.403
MSBuild SDKs: /Library/Frameworks/Mono.framework/Versions/5.16.0/lib/mono/msbuild/15.0/bin/Sdks

=== Xamarin.Profiler ===

Version: 1.6.4
Location: /Applications/Xamarin Profiler.app/Contents/MacOS/Xamarin Profiler

=== Apple Developer Tools ===

Xcode 10.1 (14460.46)
Build 10B61

=== Xamarin.Mac ===

Version: 5.2.1.12 (Visual Studio Professional)
Hash: 65ec520f
Branch: 
Build date: 2018-12-05 12:06:09-0500

=== Xamarin.iOS ===

Version: 12.2.1.12 (Visual Studio Professional)
Hash: 65ec520f
Branch: d15-9
Build date: 2018-12-05 12:06:09-0500

=== Xamarin.Android ===

Version: 9.1.4.2 (Visual Studio Professional)
Android SDK: /Users/johnny/Library/Developer/Xamarin/android-sdk-macosx
	Supported Android versions:
		7.0 (API level 24)
		7.1 (API level 25)
		8.1 (API level 27)

SDK Tools Version: 26.1.1
SDK Platform Tools Version: 28.0.1
SDK Build Tools Version: 27.0.3

Java SDK: /Users/johnny/Library/Developer/Xamarin/jdk/microsoft_dist_openjdk_1.8.0.9
openjdk version "1.8.0-9"
OpenJDK Runtime Environment (build 1.8.0-9-microsoft-b00)
OpenJDK 64-Bit Server VM (build 25.71-b00, mixed mode)

Android Designer EPL code available here:
https://github.com/xamarin/AndroidDesigner.EPL

=== Android Device Manager ===

Version: 7.7.1.0
Hash: 06ceaea1

=== Xamarin Inspector ===

Version: 1.4.3
Hash: db27525
Branch: 1.4-release
Build date: Mon, 09 Jul 2018 21:20:18 GMT
Client compatibility: 1

=== Build Information ===

Release ID: 707020021
Git revision: f1fea53df9eb0bb5890a9563c0d7ea7b03922144
Build date: 2018-12-14 18:37:35+00
Build branch: release-7.7
Xamarin extensions: 9c5cea335e6a9ce4ccfde31c4aa06c25a3576085

=== Operating System ===

Mac OS X 10.14.2
Darwin 18.2.0 Darwin Kernel Version 18.2.0
    Mon Nov 12 20:24:46 PST 2018
    root:xnu-4903.231.4~2/RELEASE_X86_64 x86_64

=== Enabled user installed extensions ===

Prism Template Studio and Developer Toolkit 2.2.0.434

I’m using Xamarin.Mac not Xamarin.Forms.

attaching CanvasView_PaintSurface to a dummy SKGLView object works fine. I will look into my initialization method tomorrow and check what I can share. I’m happy to send you some source files via email. Thank you