Byte Image Rotation in .Net Core - asp.net-web-api

Question

I've an IFormFile image file (from postman as form data), which I convert into byte array. Before converting it into byte array, I want to rotate it into its actual position (if user input image as 90°(right). I'm implementing web api in asp.net core 2.0.
byte[] ImageBytes = Utils.ConvertFileToByteArray(model.Image);
public static byte[] ConvertFileToByteArray(IFormFile file)
{
using (var memoryStream = new MemoryStream())
{
file.CopyTo(memoryStream);
return memoryStream.ToArray();
}
}
Any help, Thanks in advance.

Answer 1

In my project I need to crop and resize the images users upload. And I am using a fantastic library called ImageSharp from Six Labors. You can use its image processor to do the transformation such as Resize, Crop, Skew, Rotate and more!
Install via NuGet
I am actually using their nightly build through MyGet.
Visual Studio -> Tools -> Options -> NuGet Package Manager -> Package Sources
Hit the "Plus" button to add a new package resource
I typed "ImageSharp Nightly" as the name and put "https://www.myget.org/F/sixlabors/api/v3/index.json" as the source url.
On Browse, search "SixLabors.ImageSharp" (In my case I also need "SixLabors.ImageSharp.Drawing" but in your case you might only need to core library. Always refer back to their documentations).
Crop & Resize
using SixLabors.ImageSharp;
using SixLabors.ImageSharp.Formats;
using SixLabors.ImageSharp.Processing;
using SixLabors.ImageSharp.Processing.Transforms;
using SixLabors.Primitives;
using System.IO;
namespace DL.SO.Project.Services.ImageProcessing.ImageSharp
{
public CropAndResizeResult CropAndResize(byte[] originalImage,
int offsetX, int offsetY, int croppedWidth, int croppedHeight,
int finalWidth, int finalHeight) : IImageProcessingService
{
IImageFormat format;
using (var image = Image.Load(originalImage, out format))
{
image.Mutate(x => x
// There is .Rotate() you can call for your case
.Crop(new Rectangle(offsetX, offsetY, croppedWidth, croppedHeight))
.Resize(finalWidth, finalHeight));
using (var output = new MemoryStream())
{
image.Save(output, format);
// This is just my custom class. But see you can easily
// get the processed image byte[] using the ToArray() method.
return new CropAndResizeResult
{
ImageExtension = format.Name,
CroppedImage = output.ToArray()
};
}
}
}
}
Hope this helps you - from a big fan of ImageSharp library!

Answer 2

Magick.NET, The ImageMagick wrapper for .Net Core can be used for many file manipulations, see https://github.com/dlemstra/Magick.NET

Answer 3

byte[] byt = System.IO.File.ReadAllBytes(filePath);
System.IO.MemoryStream ms = new System.IO.MemoryStream(byt);
using (Image img = Image.FromStream(ms))
{
RotateFlipType r = angle == 90 ? RotateFlipType.Rotate90FlipNone : RotateFlipType.Rotate270FlipNone;
img.RotateFlip(r);
img.Save(filePath);
}
Using your existing code you can do the following