Add .NET5 support

[prepare]

The 3 main repositories (HtmlRender, PixelFarm, Typography)
will be moved to .netcore3 and beyond

:)

[charlesroddie]

netcore3 is not a good idea. netcore3 does not support Xamarin.iOS/Xamarin.Android/UWP.
netstandard2.0 is the right target, and will be until dotnet5.

[prepare]

OK

C# 8 + netstandard 2.1

73934c3

[charlesroddie]

netstandard2.1 removes .net framework and uwp support so I would recommend netstandard 2.0
dotnet/standard#1330

[prepare]

Thank you!
netstandard 2.0 + C#8 => OK , e3437ed

:)

[Happypig375]

@prepare I recommend using https://www.nuget.org/packages/Nullable/ for nullable annotation attributes for Nullable Reference Types and https://www.nuget.org/packages/System.Memory/ for using Span and friends in .NET Standard 2.0.

[zwcloud]

nullable -1
Span +1

[prepare]

@zwcloud, please explain

nullable -1
Span +1

[charlesroddie]

This should be reopened as there are still netframework2 projects in this repo!

#191 (comment)

.NET Framework 4.6.1 was introduced 5 years ago. What is the need to support older .net frameworks? It is bound to make this repo a huge mess.

[prepare]

see : https://docs.microsoft.com/en-us/nuget/create-packages/multiple-target-frameworks-project-file

Why I need to support .net framework 2.0

I still need to maintenance it.
My 'customers' (MANY) still need to use it in very old machine.
OR they merge my code with their projects => must be built on .netframework 2.0

I want them to update but I can't at this time.

please understand me too :)

my long term plan=> move to .net5

[charlesroddie]

These users are still on XP? So they don't mind that they haven't updated their hardware for 11 years, haven't had OS feature updates for 12 years and security updates for 6 years so are blocked from accessing the internet, but they still want to receive updates from LayoutFarm?? You post these updates to them on floppy discs?

[prepare]

Most of machines are Win7 (.net2.0-3.5) , behind corporation firewall, blocked from accessing to internet.

a very few numbers are WinXP.

They are replacing the old machine with the new Win10 machines.

[prepare]

.NET5 WIP soon
:)

[charlesroddie]

dotnet5 was scaled back so doens't support Android/iOS/UWP, with these plans pushed back to dotnet6. Regardless, a first step is to go netstandard2.0 only.

They are replacing the old machine with the new Win10 machines.

How is this process going?

[prepare]

Regardless, a first step is to go netstandard2.0 only.

OK :)

They are replacing the old machine with the new Win10 machines.

The process will be finished about this December 2020.
and I will remove old projects for .net2.0-3.5 in this December too.

[virzak]

.Net 5 is compatible with .NetStandard2. Is there a reason to separate them? I. e. will this library benefit of .Net 5.0 APIs which are not available in .Net Standard 2.0?

If not, there is no reason to separately target .Net 5.

❌ AVOID multi-targeting as well as targeting .NET Standard, if your source code is the same for all targets.

The .NET Standard assembly will automatically be used by NuGet. Targeting individual .NET implementations increases the *.nupkg size for no benefit.