Add deferred primitive helper for group

[nyaray]

Description

I noticed that code was getting a bit messy and wanted to put grouping options before the group children.

Motivation and Context

I found that mix formated code ended up looking messy as well as hard to read (as a human) since it put, for example, translation options far away from the group_spec call.

I don't think large graphs get much cleaner than this, without a bit of effort in how specs are represented:

@graph Graph.build(font: :roboto, font_size: 16)
        |> add_specs_to_graph([
          group_spec_r([t: {0, 500}], [
            group_spec_r([t: {500, 0}], [
              button_spec("button 1", t: {0, 0}),
              button_spec("button 2", t: {50, 0})
            ]),
            group_spec_r([t: {600, 0}], [
              button_spec("button A", t: {0, 0}),
              button_spec("button B", t: {50, 0})
            ])
          ]),
          group_spec_r([t: {140, 0}], [
            # this was left out in the other example because it cluttered it
            group_spec_r([t: {0, 110}], [
              Rotary.rotary_spec(0.0, id: {:chan, {:lmf, :q}}, mode: :fill, t: {180, 0}),
              Rotary.rotary_spec(0.0, id: {:chan, {:hmf, :q}}, mode: :fill, t: {220, 0})
            ]),
            # this was left out in the other example because it cluttered it
            group_spec_r([t: {0, 160}], [
              Rotary.add_to_graph(0.0, id: {:chan, {:hpf, :hz}}, mode: :fill, t: {100, 0}),
              Rotary.add_to_graph(0.0, id: {:chan, {:lf, :hz}}, mode: :fill, t: {140, 0}),
              Rotary.add_to_graph(0.0, id: {:chan, {:lmf, :hz}}, mode: :fill, t: {180, 0}),
              Rotary.add_to_graph(0.0, id: {:chan, {:hmf, :hz}}, mode: :fill, t: {220, 0}),
              Rotary.add_to_graph(0.0, id: {:chan, {:hf, :hz}}, mode: :fill, t: {260, 0}),
              Rotary.add_to_graph(0.0, id: {:chan, {:lpf, :hz}}, mode: :fill, t: {300, 0})
            ]),
            group_spec_r([t: {0, 350}], [
              Rotary.rotary_spec(0.50, id: {:chan, {:lf, :db}}, mode: :center, t: {0, 0}),
              Rotary.rotary_spec(0.50, id: {:chan, {:lmf, :db}}, mode: :center, t: {40, 0}),
              Rotary.rotary_spec(0.50, id: {:chan, {:hmf, :db}}, mode: :center, t: {80, 0}),
              Rotary.rotary_spec(0.50, id: {:chan, {:hf, :db}}, mode: :center, t: {120, 0})
            ])
          ])
        ])

The most readable I've found I can get it without group_spec_r is the following, but lines are wasted instead...

@top_button_grid [
  group_spec(
    [
      button_spec("button 1", translate: {0, 0}),
      button_spec("button 2", translate: {50, 0})
    ],
    translate: {500, 0}
  ),
  group_spec(
    [
      button_spec("button A", translate: {0, 0}),
      button_spec("button B", translate: {50, 0})
    ],
    translate: {600, 0}
  )
]

@chan_q ...

@chan_f ...

@chan_db [
  Rotary.rotary_spec(0.50, id: {:chan, {:lf, :db}}, mode: :center, translate: {0, 0}),
  Rotary.rotary_spec(0.50, id: {:chan, {:lmf, :db}}, mode: :center, translate: {40, 0}),
  Rotary.rotary_spec(0.50, id: {:chan, {:hmf, :db}}, mode: :center, translate: {80, 0}),
  Rotary.rotary_spec(0.50, id: {:chan, {:hf, :db}}, mode: :center, translate: {120, 0})
]

@top_controls [
  group_spec(@chan_q, translate: {0, 110}),
  group_spec(@chan_f, translate: {0, 160}),
  group_spec(@chan_db, translate: {0, 350})
]

@top_groups [
  group_spec(@top_button_grid, translate: {0, 500}),
  group_spec(@top_controls, translate: {140, 0})
]

@graph Graph.build(font: :roboto, font_size: 16)
       |> add_specs_to_graph(@top_groups)

Types of changes

• Bug fix (a non-breaking change which fixes an issue)
• New feature (a non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to
  not work as expected)
• Improvement/refactoring (non-breaking change that doesn't add any feature
  but make things better)

Checklist

• Check other PRs and make sure that the changes are not done yet.
• The PR title is no longer than 64 characters.

[codecov]

Codecov Report

Merging #163 into master will decrease coverage by 0.01%.
The diff coverage is 80%.

@@            Coverage Diff             @@
##           master     #163      +/-   ##
==========================================
- Coverage   85.88%   85.87%   -0.02%     
==========================================
  Files          87       87              
  Lines        2338     2343       +5     
==========================================
+ Hits         2008     2012       +4     
- Misses        330      331       +1

Impacted Files	Coverage Δ
lib/scenic/primitives.ex	93.15% <80%> (-0.97%)	⬇️

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[boydm]

Hey. This is... beautiful.

I'm up to my neck in some other code, but am planning to get back to Scenic updates soon. This will go in for sure.

[nyaray]

Thanks, I'm glad you like it! I had some other ideas about writing something interpreter-y so that graphs could be even more concise (preferring data over functions over macros) with the added benefit of that it would later be easier to build that UI editor that's been mentioned, but then I thought "no, just get something done." Maybe next time 😬

No worries, it'll go in when it goes in.