Manipulating images with .NET Core

Question

I have updated my project from .NET 4.5 to .NET Core (with ASP.NET Core). I had some very simple code in my previous version that used the bitmap object from System.Drawing to resize an image.

As I understand System.Drawing cannot be used in .NET Core because it is not cross platform, but what can be used instead?

I have googled this and cannot find anything. The only thing I can find is this post, which has no code on it what so ever.

Answer 1

Disclaimer: This is my software.

I'm working on a cross-platform 2D Graphics library that runs on .NET Core It's currently alpha but already supports a comprehensive feature set.

https://github.com/JimBobSquarePants/ImageSharp

Example usage.

using (FileStream stream = File.OpenRead("foo.jpg"))
using (FileStream output = File.OpenWrite("bar.jpg"))
{
    Image image = new Image(stream);
    image.Resize(image.Width / 2, image.Height / 2)
         .Greyscale()
         .Save(output);
}

Answer 2

You can use now official (from Microsoft) System.Drawing.Common NuGet package.

---

Note that's it's Windows-only starting from .NET 6 (it used to be cross-platform for .NET Core and .NET 5). It will still work in .NET 6 with special switch on other platforms.

From Microsoft docs recommended action:

To use these APIs for cross-platform apps, migrate to one of the following libraries:

• ImageSharp
• SkiaSharp
• Microsoft.Maui.Graphics

Alternatively, you can enable support for non-Windows platforms in .NET 6 by setting the System.Drawing.EnableUnixSupport runtime configuration switch to true in the runtimeconfig.json file:

{
   "configProperties": {
      "System.Drawing.EnableUnixSupport": true
   }
}

This configuration switch was added to give cross-platform apps that depend heavily on this package time to migrate to more modern libraries. However, non-Windows bugs will not be fixed. In addition, this switch has been removed in .NET 7.

Answer 3

I've found an implementation of System.Drawing for .NET Core based on Mono's sources being maintained at:

• https://github.com/CoreCompat/CoreCompat

The NuGet package is at:

• https://www.nuget.org/packages/CoreCompat.System.Drawing

Which you can reference it in your .NET Core App's project.json with:

{
  "dependencies": {
    "CoreCompat.System.Drawing": "1.0.0-beta006",
    ...
  },
}

Answer 4

Aspose.Drawing can manipulate images using API compatible with System.Drawing, fully managed and cross-platform with .NET Core 2.0+ support. (I'm one of the developers.)