Generate no figure file (for use in the notebook)

[leouieda]

When using the Jupyter notebook, one doesn't necessarily want a figure file on disk in the end. The embedded PNG in the notebook is enough.

There needs to be an option for begin, end, figure to say that I don't want any outputs when calling end.

[leouieda]

Right now, gmt figure requires a prefix argument and gmt end always pulls the .ps from the temp folder because it's assumed that you want a figure file in the end. But when working in the notebook we might not want a figure file. Most times, the user just wants to see the figure inline. My plans for that are to make a hidden call to gmt.psconvert inside gmt.end() to get a PNG image in memory and insert that into the notebook. This wouldn't generate any files in the current directory.

A few needed for this to work:

• Some way to tell "end" that no figure should be made.
• Allow "figure" to receive no arguments.

Not saving a figure should probably be the default behavior in Python (like matplotlib).
We could add an argument to gmt.figure and/or gmt.begin (maybe save=True) to indicate that we want a saved figure in the end.
Another option would be to only save when explicitly provided the figure format.
This doesn't need to happen on the C API side. It can be done in Python (if no format is given, then indicate to the C API that "end" shouldn't create the files).