Byte[r,c,c] to Halcon HObject/HImage to byte[] - halcon

Question

I am using Zivid.NET, Halcon.NET and ML.NET together. Zivid provides me with a 3D byte array (row, column, channel), Halcon uses HImages/HObjects, ML.NET functionality expects a 1D byte array (same as File.ReadAllBytes())
So far I used a workaround where:
I save()'d Zivid's imageRGBA as a PNG,
which I read with Halcon's read_image() that gives me a HObject.
After some graphical work I saved the HObject again as a PNG using write_image().
Using File.ReadAllBytes() to read that PNG I get the byte[] that my ML.NET functionalities expect.
But this is far from ideal with larger amounts of data.
What I need is:
a way to convert byte[r,c,c] images to HObject/HImage.
a way to convert HObject/HImage images to byte[].
Halcon's read_image() and write_image() don't seem to have any options for this and I haven't found anything helpful so far.

Answer 1

To create an HImage object from byte, you need a pointer to an array and then it's simple:
public HImage(string type, int width, int height, IntPtr pixelPointer)
To get a pointer and acess the data from HImage, the following function is needed:
IntPtr HImage.GetImagePointer1(out string type, out int width, out int height)

Answer 2

To convert from Zivid.NET's byte[r,c,c] to HImage one can:
var byteArr = imgRGBA.ToByteArray();
byte[,] redByteArray = new byte[1200, 1920];
byte[,] greenByteArray = new byte[1200, 1920];
byte[,] blueByteArray = new byte[1200, 1920];
for (int row = 0; row < 1200; row++)
for (int col = 0; col < 1920; col++)
{
redByteArray[row, col] = byteArr[row, col, 0];
greenByteArray[row, col] = byteArr[row, col, 1];
blueByteArray[row, col] = byteArr[row, col, 2];
}
GCHandle pinnedArray_red = GCHandle.Alloc(redByteArray, GCHandleType.Pinned);
IntPtr pointer_red = pinnedArray_red.AddrOfPinnedObject();
GCHandle pinnedArray_green = GCHandle.Alloc(greenByteArray, GCHandleType.Pinned);
IntPtr pointer_green = pinnedArray_green.AddrOfPinnedObject();
GCHandle pinnedArray_blue = GCHandle.Alloc(blueByteArray, GCHandleType.Pinned);
IntPtr pointer_blue = pinnedArray_blue.AddrOfPinnedObject();
GenImage3(out HObject imgHImage, "byte", 1920, 1200, pointer_red, pointer_green, pointer_blue);
pinnedArray_red.Free();
pinnedArray_green.Free();
pinnedArray_blue.Free();
Still working on the second part..
A better / more efficient method is very welcome.