manipulate images in Blazor Client-side

Question

User1461220549 posted

Hi there,

I need to change resolution of an Image on Blazor Client-Side.

I tried with this code:

    public static class IncreaseImgResolution
    {
        public static async Task<string> IncreaseDpi(string base64IngString, float moltiplicatioFactor)
        {
            return await Task.Run(() => EnchangeImgDpi(base64IngString, moltiplicatioFactor));
        }

        private static string EnchangeImgDpi(string base64IngString, float moltiplicatioFactor)
        {
            byte[] imageBytes = Convert.FromBase64String(base64IngString);
            var ms = new MemoryStream(imageBytes, 0, imageBytes.Length);
            var OriginalBitmap = new Bitmap(ms);
            var vertRes = OriginalBitmap.VerticalResolution * moltiplicatioFactor;
            var horRes = OriginalBitmap.HorizontalResolution * moltiplicatioFactor;
            OriginalBitmap.SetResolution(horRes, vertRes);
            using (var stream = new MemoryStream())
            {
                OriginalBitmap.Save(stream, System.Drawing.Imaging.ImageFormat.Png);
                var str = stream.ToArray();
                return Convert.ToBase64String(str);
            }
        }
    }

But I retrieve following error:

blazor.webassembly.js:1 WASM: System.PlatformNotSupportedException: Operation is not supported on this platform.

At following line of code:

var OriginalBitmap = new Bitmap(ms);

So, I think System.Drawing is not working on webassembly.

I would like to know if somebody can suggest some workaround or alternative solutions.

Thank you