feat(plotnine): implement violin-grouped-swarm

[github-actions]

Implementation: violin-grouped-swarm - plotnine

Implements the plotnine version of violin-grouped-swarm.

File: plots/violin-grouped-swarm/implementations/plotnine.py

Parent Issue: #3529

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🤖 impl-generate workflow

[claude]

AI Review - Attempt 1/3

Image Description

The plot displays a grouped violin chart with swarm overlay showing response times (in milliseconds) across three task types (Simple, Moderate, Complex) and two expertise levels (Novice in steel blue, Expert in golden yellow). Each violin shape effectively shows the distribution of data, with individual data points rendered as jittered markers inside the violins. The Novice group consistently shows higher response times than Expert across all task complexity levels. Response times increase from Simple (~300-500ms) to Moderate (~400-900ms) to Complex (~600-1400ms). The violins have semi-transparent fills (alpha ~0.5) allowing the swarm points to remain visible. The title uses the correct format: 'violin-grouped-swarm · plotnine · pyplots.ai'. The legend is positioned on the right side, clearly labeling the two expertise levels with matching colors.

Quality Score: 91/100

Criteria Checklist

Visual Quality (37/40 pts)

• VQ-01: Text Legibility (10/10) - Title at 24pt, axis labels at 20pt, tick labels at 16pt - all perfectly readable
• VQ-02: No Overlap (8/8) - No overlapping text elements, violins well-spaced
• VQ-03: Element Visibility (7/8) - Swarm points visible, though slightly small for the data density; violins well-sized
• VQ-04: Color Accessibility (5/5) - Blue and yellow palette is colorblind-safe, excellent contrast
• VQ-05: Layout Balance (5/5) - Good proportions, plot fills canvas well, balanced margins
• VQ-06: Axis Labels (2/2) - Y-axis includes units 'Response Time (ms)', X-axis labeled 'Task Type'
• VQ-07: Grid & Legend (0/2) - Grid is subtle (alpha 0.3), but legend shows duplicate entries (Expertise appears twice with same colors)

Spec Compliance (23/25 pts)

• SC-01: Plot Type (8/8) - Correct grouped violin plot with swarm overlay
• SC-02: Data Mapping (5/5) - Category on x-axis, values on y-axis, grouping by color/hue
• SC-03: Required Features (3/5) - Has violins, swarm points, grouping, transparency; however swarm points use jitter rather than true swarm positioning (spec mentions 'dodging swarm points to align')
• SC-04: Data Range (3/3) - All data visible within axes
• SC-05: Legend Accuracy (2/2) - Legend correctly identifies Novice and Expert groups
• SC-06: Title Format (2/2) - Correct format '{spec-id} · {library} · pyplots.ai'

Data Quality (20/20 pts)

• DQ-01: Feature Coverage (8/8) - Shows varying distributions across complexity levels and expertise, different spreads visible
• DQ-02: Realistic Context (7/7) - Response time across task complexity is a real, neutral, plausible scenario
• DQ-03: Appropriate Scale (5/5) - Response times in 200-1400ms range are realistic for cognitive tasks

Code Quality (9/10 pts)

• CQ-01: KISS Structure (3/3) - Simple imports → data → plot → save structure
• CQ-02: Reproducibility (3/3) - np.random.seed(42) set
• CQ-03: Clean Imports (1/2) - All imports used, but guide_legend import may be unnecessary (default behavior)
• CQ-04: No Deprecated API (1/1) - Uses current plotnine API
• CQ-05: Output Correct (1/1) - Saves as 'plot.png'

Library Features (2/5 pts)

• LF-01: Distinctive Features (2/5) - Uses plotnine's grammar of graphics with layered geoms and position_dodge, but doesn't use more advanced features like geom_sina (not available) or stat_summary. Uses geom_jitter instead of proper swarm positioning.

Strengths

• Excellent color palette with high contrast (blue/yellow) that is colorblind-safe
• Clean layered grammar of graphics approach with geom_violin + geom_jitter
• Realistic and well-thought-out data scenario with varying complexity levels and expertise
• Proper use of position_dodge to align grouped elements
• Text sizing follows guidelines perfectly for 4800×2700 output

Weaknesses

• Legend appears with duplicate 'Expertise' entries (both fill and color scales create separate legend items)
• Uses geom_jitter for swarm points rather than true swarm positioning - plotnine lacks native geom_beeswarm
• The guides() call with guide_legend() doesn't effectively merge the legends

Verdict: APPROVED