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i am receving the byte pointer from c++ it holds the address of the image,i need to get the thumbnail from the byte pointer address is it possible?

What I have tried:

what I tried is after getting the address i marshall to convert the byte pointer into byte array then i pass the byte array to get the thumbnail then i will get the thumbnail. now the problem is when i have large size file in byte array while marshaling it takes time

to reduce this time without marshalling the byte pointer i need to get the thumbnail

my code is

byte[] managedArray = new byte[img.nsize];//img.nsize //size of memory to be allocated
Marshal.Copy(img.pBitmap, managedArray, 0, (int)img.nsize); //img.pBitmap->byte pointer
byte[] Temp1 = MakeThumbnail(managedArray, 200, 200);

public static byte[] MakeThumbnail(byte[] myImage, int thumbWidth, int thumbHeight)
         using (MemoryStream ms = new MemoryStream())
         using (Image thumbnail = Image.FromStream(new MemoryStream(myImage)).GetThumbnailImage(thumbWidth, thumbHeight, null, new IntPtr()))
             thumbnail.Save(ms, System.Drawing.Imaging.ImageFormat.Png);
             return ms.ToArray();
Gerry Schmitz 12-Jul-21 14:08pm    
The image either doesn't have a thumbnail; or the image you're handling is "too big" to make a sensible thumbnail; or it's not working at all. Start somewhere. (Anything near 300x300 is considered "big")
Fazil13 13-Jul-21 16:02pm    
Yes thanks now, I solved this i sent a whole image byte pointer instead of thumbnail pointer from dll and converted in to a thumbnail in my main application.

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