Ytukyg

First, I've read the a few questions regarding this issue, the most helpful being:
Passing bitmap from c# to c++

I was unable to get the provided solutions to work as I kept getting an AccessViolationException.

What I'm attempting to do is pass bitmap data to an unmanaged c++ dll. To do this I created a struct which holds a pointer to the image data as well as its length. I'm using a struct as I plan on passing in multiple images (in a single call) to the unmanaged API.

What I implemented works but I have a feeling there is probably some serious drawbacks so I'm curious as to what those drawbacks could be.

My current solution uses a generic pointer to hold the image data. This of course would be a drawback as I lose type safety. Anyway here is the relevant code.

c++ dll

raw_image.h

struct raw_image

{

   void* data;

   int size;

};

alignment.cpp (exports)

ALIGNMENT_API void submit( raw_image& img )

{

    cv::Mat mat = cv::imdecode( cv::_InputArray(

        static_cast<uchar*>( img.data ), img.size ), cv::IMREAD_COLOR );

    cv::imshow( "image", mat );

    cv::waitKey( );

    cv::destroyWindow( "image" );

}

C# dll

RawImage.cs

[StructLayout( LayoutKind.Sequential )]

internal unsafe struct RawImage

{

    internal void* ImageData;

    internal int Length;

}

Aligner.cs (import)

[DllImport( "alignment-vc141-mtd-x64.dll", CallingConvention = 

 CallingConvention.Cdecl )]

    static extern void submit( RawImage img );

And this is where I pass the image to the unmanaged API.

using( var bitmap = new Bitmap( "AlignmentCenter.jpg" ) )

using( var stream = new MemoryStream( ) )

{

    bitmap.Save( stream, ImageFormat.Jpeg );

    var source = stream.ToArray( );

    fixed( void* ptr = source )

    {

        var raw = new RawImage

        {

            ImageData = ptr,

            Length = source.Length

        };

        submit( raw );

     }

  }

Is what I'm doing unsafe? Am I copying more than I should?
One last thing, I know about EmguCv and I've used it in the past but I won't be using it here.