ZPL Graphic Field Z64 Data Encoding

I am developing a .NET application that will dynamically create a ZPL file containing a user specified graphic then send to a Zebra printer. I am using ZebraDesigner v2.5.0 as a starting point for creating the ZPL file. This application outputs graphics as ^GFA,b,c,d,:Z64:data:cccc. The ZPL II manual describes Z64 as a format using LZ77 compression with Base64 encoding but doesn't provide many specifics. I have tried numerous algorithms and graphic formats but have been unsuccessful in generating the correct Z64 encoded data.

My questions are:

  1. Does the current Zebra SDK incorporate the Z64 encoding algorithms?
  2. Is source code available that generates the proper image format, compresses, encodes, then calculates a checksum for the Z64 encoding?
  3. Is there a document that describes which LZ77 algorithm is used to compress the image?
  4. What image / pixel format is required before compressing the data?
  5. How are the parameters b, c, and d calculated when using the Z64 encoding?
  6. Does ZebraDesigner offer an API that could be used to gain access to the Z64 algorithm?
  7. What minimum printer firmware is required to recognize the Z64 encoding?