Should we set -J and -B defaults in modern mode (after `gmtbegin`)?

[adigitoleo]

Currently, when using modern mode the defaults for projection (-J) and frame (-B) are not set, for example:

julia> basemap(region = :g, show = true)  # Works because it sets implicit defaults for -J and -B

julia> gmtbegin()

julia> basemap(region = :g)
basemap [ERROR]: Must specify at least one of -A, -B, -D, -L, -T
ERROR: Something went wrong when calling the module. GMT error number = 71
Stacktrace:
 [1] gmt(cmd::String, args::Nothing)
   @ GMT ~/.julia/packages/GMT/lcweZ/src/gmt_main.jl:283
 [2] finish_PS_module(d::Dict{Symbol, Any}, cmd::Vector{String}, opt_extra::String, K::Bool, O::Bool, finish::Bool, args::Nothing)
   @ GMT ~/.julia/packages/GMT/lcweZ/src/common_options.jl:3399
 [3] basemap(cmd0::String, arg1::Nothing; first::Bool, kwargs::Base.Iterators.Pairs{Symbol, Symbol, Tuple{Symbol}, NamedTuple{(:region,), Tuple{Symbol}}})
   @ GMT ~/.julia/packages/GMT/lcweZ/src/psbasemap.jl:67
 [4] top-level scope
   @ REPL[43]:1

julia> gmtend()

julia> basemap(region = :g, Vd = 2)
"psbasemap  -Rg -JX14c/0 -Baf -BWSen -P -K > /tmp/GMTjl_tmp.ps"

julia> gmtbegin()

julia> basemap(region = :g, Vd = 2)
"basemap  -Rg"

julia> gmtend()

It happens with the other functions as well of course (not just basemap). I think the defaults that are set in classic mode are quite nice, so maybe it wouldn't hurt to use them in modern mode as well? I'm not sure anything is lost by doing this: if the user wants a different projection/frame, they can still override the defaults. Also, the behaviour becomes more consistent with classic mode.

I can have a go at a patch (probably not before the weekend) if you're short on time. Just thought I'd raise the point.

Cheers

[adigitoleo]

Related to #667 , the new frame = :auto option works in modern mode and can be used as a workaround ono current master:

julia> gmtbegin("mapdraft.pdf")

julia> basemap(region = :g, frame = :auto)

julia> gmtend(show = true)

[joa-quim]

This is an easy one. Yes you are right, it should have the same defaults. I confess that I rarely use the modern mode so these type of issues go unnoticed. If you want to give it a try, please go ahead. I'll classes start shortly (start delayed still because of the covid) and need to keep working in the new RemoteS package. Also because of this, addressing your other -B issues will take longer to address.

[adigitoleo]

No worries, thanks for all the guidance so far! Hopefully you don't have to do classes online like they are here in Australia...

[joa-quim]

We had quite a big share of online classes but for now they will be insitu again.