Road to plots 2.0

[isentropic]

What changed

• No default backend
• Backends are purely extensions with no 'requires'
• The internals are more organized into modules and moved around, thanks to @BeastyBlacksmith
• Backend init and backend code is only found in its extensions, this should help with backend interference and annoyances about initialization and precompilation of plots. This should make backends modular and implemented much easier and without hacks into Plots.jl codebase

Example:

using Plots; import UnicodePlots
unicodeplots()
plot(1:10)

What works

• GR
• UnicodePlot
• 90% of tests pass
• Precompilation

What does not work

Help needed here add more items or resolve the ticks.

• GR backend has weird axis issue I never got to solve, unicode works consistently same
• plotly backend
• pythonplot backend
• pgfplotsx backend
• gaston backend
• default not resetting legend args

Help needed:

• Rebase on the master branch
• Report breakages
• Fix GR backend via help of git diff, something must've changed in GR code
• move documentation back into this repo
• Start updating the docs
• Propose other breaking changes
• Update the news.md
• organize a community poll of what defaults could be tweaked and other wishes

Decisions to be made

• Deprecate inspectDR?
• Move to column major order?
• Change the defaults

Issues needing attention please add more or checkoff resolved:
#4565 (comment)
Copy of that:
Labeled issues:

• [FR] change minorticks semantics #4532
• [FR] auto ylim calculation #4028
• [FR] Safe figure saving #3001
• [BUG] Cycling arguments #2980
• support scalars for hline! and vline! #2129
• Should layout be column major? #2047
• [FR] PythonPlot/PythonCall alternative to PyPlot/PyCall #4181
• [FR] Use Preferences.jl to configure default loaded backend #4513
• [FR] remove explicit GR dependency from Project.toml #4631
• [BUG] Inconsistency With Measurement Units In API #4350
• [FR] redesign backend dependencies #4567
• [FR] Harmonize how series data are used #4596

Labeled PRs:

• cleanup: drop deprecated pgfplots #4326
• GR margin 0-point set to allow no padding #3942
• Reduce number of exported names #3744
• Rework adding legends #3732
• WIP: Fonts #3473
• Remove StatsPlots warnings #3357
• Move @df macro to Plots #3351
• Rework adding legends Rework adding legends #3732

---

Closes #4326

[BeastyBlacksmith]

Thanks for taking this one step further!

[BeastyBlacksmith]

I think we are at a point where it makes sense to merge this and then iterate on. I'll copy the OP to the new PR.