PLUGIN for Alpha creation

Hello friends,can you folks create some Zscript/Zplugin for exporting the alpha created.
The steps are as:
1.an alpha is created on a plane or cube.
2. Document is resized to 1024 by 1024 or 512 by 512(an option box may be)
3.New document created with the previously mentioned (1024?512) size.
4.the created plane or cube containing the created alpha sculpt is brought in.
5.Plane/Cube containing the Alpha is resized in the canvas to fit it completely.
7. Export grabbed alpha ,Rename it
8.Resize the document to the previous size of 1920 by 1080 or any other(Option Box).

This would be very helpful…Thanks ye all!