Auto-layout mode that prevents plots from shrinking beyond readability

[BioTurboNick]

This is a first pass that probably doesn't account for everything needed.

However, what it does is it simply computes a row and column count, the widths and sizes of them, passes the work down to the normal layout method, then the calling plot code reads the height and width attributes from the layout and overrides size if the total size needed is larger than the set size.

plot([plot(rand(3)) for x ∈ 1:20]..., layout = :auto, legend = :none)

Current:

This PR:

[BioTurboNick]

Currently has a bias for taller over wider, but I can change that.

[codecov]

Codecov Report

Merging #4234 (5fafc16) into master (6266ff8) will decrease coverage by 0.34%.
The diff coverage is 3.03%.

@@            Coverage Diff             @@
##           master    #4234      +/-   ##
==========================================
- Coverage   77.93%   77.58%   -0.35%     
==========================================
  Files          28       28              
  Lines        7101     7134      +33     
==========================================
+ Hits         5534     5535       +1     
- Misses       1567     1599      +32     

Impacted Files	Coverage Δ
src/args.jl	74.47% <ø> (ø)
src/layouts.jl	70.57% <0.00%> (-5.83%)	⬇️
src/plot.jl	71.53% <20.00%> (-1.96%)	⬇️

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[BeastyBlacksmith]

We already have a notion for plotarea with a slightly different meaning

Plots.jl/src/types.jl

Line 39 in 6266ff8

plotarea::BoundingBox # the part where the data goes

IIIUC, your plotarea is the whole area covered by one subplot, whereas the subplot field is the area of the axes and data without labels and margins and stuff

[BioTurboNick]

Ah hmm. What would you recommend?

[BeastyBlacksmith]

call it subplotarea would be one option. This would also need an entry in arg_desc.jl

[BeastyBlacksmith]

In general this is a different thing, than I had in mind with size = :auto from our conversation on slack, but having a way to say "I don't care about the specific layout" seems useful to me nonetheless.

[BioTurboNick]

Hmm ok. Two of my pain points I'd like to resolve is being able to specify rows/columns for a grid without having to provide an exact number of plots to fill it, and prioritizing visibility of many plots over a fixed overall plot area.

How can this fit in with what you have in mind, so that they don't conflict?

[BeastyBlacksmith]

being able to specify rows/columns for a grid without having to provide an exact number of plots to fill it,

can you give an example of how you would use it, if it where implemented?

What I don't like here is that the plot size changes without the user explicitly requesting it.
Here is one idea how we could handle things:

• layout = :auto creates a layout that fits all plots "optimally" in the given size
• size = :auto indicates that the overall plot size is allowed to change

Then you could have an automatic layout that changes plot size with layout = :auto and size = :auto. It might also be an option to check whether we can use GridLayoutBase.jl.
We could also think about having more descriptive modes, than just :auto maybe things like :constplotarea, :raggedright, etc.

[BioTurboNick]

being able to specify rows/columns for a grid without having to provide an exact number of plots to fill it,

can you give an example of how you would use it, if it where implemented?

I'm building Pluto notebooks for our analysis pipeline, and there can be a variable number of samples per experiment. I may know that I can comfortably fit 3 plots across but otherwise don't care how many rows it takes. Or vice versa for columns. A more specific example might be a linear trace for each event. They can get pretty short and still be legible because the length matters more.

[BeastyBlacksmith]

being able to specify rows/columns for a grid without having to provide an exact number of plots to fill it,

can you give an example of how you would use it, if it where implemented?

I'm building Pluto notebooks for our analysis pipeline, and there can be a variable number of samples per experiment. I may know that I can comfortably fit 3 plots across but otherwise don't care how many rows it takes. Or vice versa for columns. A more specific example might be a linear trace for each event. They can get pretty short and still be legible because the length matters more.

I meant in terms of function calls.

[BioTurboNick]

I meant in terms of function calls.

Ah, yes. Maybe grid() could take a symbol as an argument, say :auto? Or we could have layout objects constructed with rows(x) and cols(x), which would be easier.

Maybe we would also want a minwidth and minheight provided that subplots would use to make sure they don't shrink below that.

Maybe size could take a symbol like :fit for the grow-to-fit behavior I've imagined here?

[t-bltg]

This won't be breaking would it ?

[BioTurboNick]

I think perhaps this might be better considered as part of a revamped layout system for 2.0 than to solve here.