XMPGPano meta data to image by C# : for facebook 360 image

Question

I am making facebook 360 image by custom stitching using C#-emgu.

1. Can able to set EXIF tags(make & model) using C# image property items.

    // Sample code for set exif make tag
   
   var dummy1 = Image.FromFile(@"filePathName.jpg");
   PropertyItem pItem = dummy1.PropertyItems[0];
   string str = System.Text.Encoding.UTF8.GetString(pItem.Value);
   pItem.Id = 0x010F; // make tag id
   pItem.Type = 2;
   pItem.Value = System.Text.Encoding.UTF8.GetBytes("*****");
   pItem.Len = pItem.Value.Length;
   jpeg1.SetPropertyItem(pItem);
   

2. Cant able to set XMPGPano tags below listed by C#.

XMPGPano docs in google street view

* CroppedAreaImageHeightPixels (final image height)
* CroppedAreaImageWidthPixels (final image width)
* ProjectionType (equirectangular)
* CroppedAreaLeftPixels (No idea what it is?)
* CroppedAreaTopPixels (No idea what it is?)
* FullPanoHeightPixels (No idea what it is?)
* FullPanoWidthPixels (No idea what it is?)

Image : Sample XMPGPano tags in exif tool

3. But face book understand 360 image only if I add XMPGPano tags.

Please route me following points below..

1. Why this below tags with sample calculations

   • CroppedAreaLeftPixels (No idea what it is?)
   • CroppedAreaTopPixels (No idea what it is?)
   • FullPanoHeightPixels (No idea what it is?)
   • FullPanoWidthPixels (No idea what it is?)

2. How to add this tags programmatically C#.