Image.FromStream throws Parameter is not valid error only on linux

Question

我在 .net 核心中进行了一些单元测试，检查从 Angular 前端上传的文件是否实际上在后端调整了大小。

我有一个用于测试的服务，包含以下方法：

public byte[] ResizeImage(IFormFile formFile)
    {
        Image imgFromStream;
        using (var memStream = new MemoryStream())
        {
            formFile.CopyTo(memStream);
            memStream.Position = 0;

            Console.WriteLine("$$$$$$$ LENGTH  :" + memStream.Length);
            Console.WriteLine("$$$$$$$ CAN READ :" + memStream.CanRead);
          

   
 ->>>>>           imgFromStream = System.Drawing.Image.FromStream(memStream, false,false);

            Image thumbnail = imgFromStream.GetThumbnailImage(280, 90, () => false, IntPtr.Zero);

            var imageByteArray = new byte[0];

            using (MemoryStream mStream = new MemoryStream())
            {
                thumbnail.Save(mStream, ImageFormat.Png);
                imageByteArray = mStream.ToArray();
            }
            imgFromStream.Dispose();
            thumbnail.Dispose();
            return imageByteArray;
        }

    }

问题在于，只有在 Linux 机器上，测试才会从带有 (---->>>) 的行中失败。 我已经尝试过使用 ImageConverter，linux 对此也有不好的看法，但它仍然无法正常工作。 我没有想法。

StackTrace :   at System.Drawing.Image.InitializeFromStream(Stream stream)
at System.Drawing.Image.LoadFromStream(Stream stream, Boolean keepAlive)
at System.Drawing.Image.FromStream(Stream stream, Boolean useEmbeddedColorManagement, Boolean validateImageData)

为测试创建图像的方法：

 public Image ByteArrayToImage(byte[] byteArrayIn)
    {
        int size = (int)Math.Sqrt(byteArrayIn.Length);

        Bitmap bitmap = new Bitmap(size, size, PixelFormat.Format32bppArgb);
        BitmapData bitmapData = bitmap.LockBits(new Rectangle(0, 0, bitmap.Width, bitmap.Height), ImageLockMode.ReadWrite, bitmap.PixelFormat);

        try
        {
            for (int rowIndex = 0; rowIndex < bitmapData.Height; ++rowIndex)
                Marshal.Copy(byteArrayIn, rowIndex * bitmap.Width, bitmapData.Scan0 + rowIndex * bitmapData.Stride, bitmap.Width);
        }
        finally
        {
            bitmap.UnlockBits(bitmapData);
        }

        return bitmap;
    }

并生成byteArrayIn参数：

     private byte[] GenerateImageByteArray(int sizeInMb)
    {
        Random rnd = new Random();


        Byte[] b = new Byte[sizeInMb * 1024 * 1024]; // convert mb to byte
        rnd.NextBytes(b);

        //This conversion is needed because the GetThumbnail method from the Service will throw an error
        //A random generated byte array can not be converted into a thumbnail
        //Only if it's from an image
        var image = ByteArrayToImage(b);
        var imageByteArray = new byte[0];
        using (MemoryStream mStream = new MemoryStream())
        {
            image.Save(mStream, ImageFormat.Png);
            imageByteArray=mStream.ToArray();
        }

        return imageByteArray;
    }

Answer 1

如果你想在 linux 上使用System.Drawing.Common，你需要安装 GDI+ 支持库：

sudo apt install libc6-dev 
sudo apt install libgdiplus