Many thanks again JohnC. Using your example and Erel's "takeScreenshot" subroutine I succeeded in creating a bitmap of the graph shown above and saving that as a JPEG file to the File.DirInternal directory for my App. Just a few lines of code. However, when trying to attach the .JPEG to an e-mail I find that GMail denies access to the DirInternal folder. It is only GMail that won't attach it - an older tablet will happily list the Chart.jpg file as an attachment, but in that case (even though the Google e-mail account is correctly specified) GMail will not allow that old e-mail app to 'sign in'. (Seems odd that Google denies access to its own Android directory while allowing older e-mail apps to extract files from it, but I'm too old to be surprised at anything now.)
Trying to copy the file to DirDefaultExternal or DirRootExternal fails with a "FileNotFoundException" error and PermissionDenied when trying to open the target, even after confirming write access with File.ExternalWritable. For the simple routine below to prove so error-prone I am beginning to doubt my logic!
Log("Copying file to external(emulated)")
File.Copy(File.DirInternal,"chart.jpg",File.DirRootExternal,"graph.jpg")
Log("Copied out")
I think the principle is right and offers a solution, but access to files should be simpler than this. Any thoughts would be very welcome.
Very Best, David