Resize Images with .NET Core

June 11, 2019 1 min read BEN ABT

To resize images like PNG, JPEG, JPG and Co using .NET Core, there is no SDK support available today.

But the Microsoft Mono team has written a wrapper named SkiaSharp based on the Google library Skia , which works wonderfully and fast - but unfortunately a bit complex. The documentation can also be improved.

Snippet

Here is my snippet to resize images width SkiaSharp

C#
  public class SkiaSharpImageManipulationProvider : IImageManipulationProvider
  {
      public (byte[] FileContents, int Height, int Width) Resize(byte[] fileContents, 
      int maxWidth, int maxHeight, 
      SKFilterQuality quality = SKFilterQuality.Medium)
      {
          using MemoryStream ms = new MemoryStream(fileContents);
          using SKBitmap sourceBitmap = SKBitmap.Decode(ms);
 9
          int height = Math.Min(maxHeight, sourceBitmap.Height);
          int width = Math.Min(maxWidth, sourceBitmap.Width);
12
          using SKBitmap scaledBitmap = sourceBitmap.Resize(new SKImageInfo(width, height), quality);
          using SKImage scaledImage = SKImage.FromBitmap(scaledBitmap);
          using SKData data = scaledImage.Encode();
16
          return (data.ToArray(), height, width);
      }
  }