Running test on Linux

[Socolin]

Hello,

I saw that a lot of test are using Gdi+ in ImageSharp.Drawing, so those test cannot run on linux anymore on Linux, is there a reason to keep GDI+ (System.Drawing) for the tests, or could it be replace with ImageMagick ?

[JimBobSquarePants]

They can run on Linux, you just need to install gdiplus like we do in the CI.

System.Drawing was used as ImageMagick had issues when the tests were first written. Whether that is still the case I don't know and I don't want to invest time switching over at the moment.

What should be done however, is the readme updated to include instructions to add gdi dependencies for testing whicb can be copied from the CI yaml file.

[Socolin]

Microsoft stopped supporting System.Drawing completly in .net 8.0 on linux: https://learn.microsoft.com/en-us/dotnet/core/compatibility/core-libraries/6.0/system-drawing-common-windows-only
Is there an alternative way (non official System.Drawing) that run on linux that I missed ?

[JimBobSquarePants]

It runs as well as I need to for testing, it just isn't supported in production (as it shouldn't because there are a ton of gaps and weirdness).

[Socolin]

Are we speaking about Linux or Windows ?

I agree that for testing no need to change (I used to have it for testing on a project too until it stop working), and we still use it on Windows with no major problem (while rewriting for ImageSharp we discover multiple weird things in System.Drawing)

I'm just confuse if you are able to execute it at all on Linux, I'm getting this exception when using System.Drawing on linux, stating it's not possible anymore.

Unhandled exception. System.TypeInitializationException: The type initializer for 'Gdip' threw an exception.
 ---> System.PlatformNotSupportedException: System.Drawing.Common is not supported on non-Windows platforms. See https://aka.ms/systemdrawingnonwindows for more information.
   at System.Drawing.LibraryResolver.EnsureRegistered()
   at System.Drawing.SafeNativeMethods.Gdip.PlatformInitialize()
   at System.Drawing.SafeNativeMethods.Gdip..cctor()
   --- End of inner exception stack trace ---
   at System.Drawing.SafeNativeMethods.Gdip.GdipCreateBitmapFromScan0(Int32 width, Int32 height, Int32 stride, Int32 format, IntPtr scan0, IntPtr& bitmap)
   at System.Drawing.Bitmap..ctor(Int32 width, Int32 height, PixelFormat format)
   at System.Drawing.Bitmap..ctor(Int32 width, Int32 height)
   at Program.<Main>$(String[] args) in /tmp/gdip/Program.cs:line 3

With

using System.Drawing;

Bitmap destination = new(800, 800);

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net10.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="System.Drawing.Common" Version="6.0.0"/>
  </ItemGroup>
</Project>

[JimBobSquarePants]

That error message means you need to install libgdiplus on the Linux device. In our workflow we use apt-get to do this.

ImageSharp.Drawing/.github/workflows/build-and-test.yml

Lines 121 to 127 in 0774da7

	- name: Install libgdi+, which is required for tests running on ubuntu
	if: ${{ contains(matrix.options.os, 'ubuntu') }}
	run: |
	sudo apt-get update
	sudo apt-get -y install libgdiplus libgif-dev libglib2.0-dev libcairo2-dev libtiff-dev libexif-dev
	- name: Git Config

For Mac it's more complicated. It used to be installed on the image but now we have to do the following.

https://github.com/SixLabors/ImageSharp/blob/322935125d7e535188d38198c40652eaa46e6549/.github/workflows/build-and-test.yml#L121-L131

Note we haven't updated this repo to replace macos13 yet.

[Socolin]

About macos13, about the comment the problem seems to be arm

- os: macos-13 # macos-latest runs on arm64 runners where libgdiplus is unavailable

Should it be replaced with macos-15-intel or macos-26 ? (I can do a PR if this help)

About GDI+ on linux, I have all those packages installed, and I'm still getting the error, I'm confused 😕 It's not really a problem so I don't want to waste your time on this, if it works for you, it's all good :) (Since the CI run on multiple OS I don't mind if I can't run on my computer)

$ apt search libgdiplus 
Sorting... Done
Full Text Search... Done
libgdiplus/noble,now 6.1+dfsg-1build3 amd64 [installed]
  interface library for System.Drawing of Mono

$ apt search libgif-dev
Sorting... Done
Full Text Search... Done
libgif-dev/noble,now 5.2.2-1ubuntu1 amd64 [installed]
  library for GIF images (development)

$ apt search libglib2.0-dev
Sorting... Done
Full Text Search... Done
libglib2.0-dev/noble-updates,now 2.80.0-6ubuntu3.5 amd64 [installed]
  Development files for the GLib library

libglib2.0-dev-bin/noble-updates,now 2.80.0-6ubuntu3.5 amd64 [installed,automatic]
  Development utilities for the GLib library

$ apt search libcairo2-dev
Sorting... Done
Full Text Search... Done
libcairo2-dev/noble,now 1.18.0-3build1 amd64 [installed]
  Development files for the Cairo 2D graphics library

$ apt search libtiff-dev
Sorting... Done
Full Text Search... Done
libtiff-dev/noble-updates,noble-security,now 4.5.1+git230720-4ubuntu2.4 amd64 [installed]
  Tag Image File Format library (TIFF), development files

$ apt search libexif-dev
Sorting... Done
Full Text Search... Done
libexif-dev/noble,now 0.6.24-1build2 amd64 [installed]
  library to parse EXIF files (development files)

$ dotnet run
Unhandled exception. System.TypeInitializationException: The type initializer for 'Gdip' threw an exception.
 ---> System.PlatformNotSupportedException: System.Drawing.Common is not supported on non-Windows platforms. See https://aka.ms/systemdrawingnonwindows for more information.
   at System.Drawing.LibraryResolver.EnsureRegistered()
   at System.Drawing.SafeNativeMethods.Gdip.PlatformInitialize()
   at System.Drawing.SafeNativeMethods.Gdip..cctor()
   --- End of inner exception stack trace ---
   at System.Drawing.SafeNativeMethods.Gdip.GdipCreateBitmapFromScan0(Int32 width, Int32 height, Int32 stride, Int32 format, IntPtr scan0, IntPtr& bitmap)
   at System.Drawing.Bitmap..ctor(Int32 width, Int32 height, PixelFormat format)
   at System.Drawing.Bitmap..ctor(Int32 width, Int32 height)
   at Program.<Main>$(String[] args) in /tmp/gdip/Program.cs:line 3