feat(letsplot): implement waffle-basic

[github-actions]

Implementation: waffle-basic - letsplot

Implements the letsplot version of waffle-basic.

File: plots/waffle-basic/implementations/letsplot.py

Parent Issue: #998

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🤖 impl-generate workflow

[claude]

AI Review - Attempt 1/3

Image Description

The plot displays a 10×10 waffle chart (100 squares) with a title "waffle-basic · letsplot · pyplots.ai" at the top. The grid is filled from top-left to bottom-right with four distinct colors representing market share categories:

• Blue (#306998) - Product A: 42 squares in the top 4 rows plus 2 squares in row 5 (42%)
• Yellow (#FFD43B) - Product B: 28 squares spanning rows 5-7 (28%)
• Green (#4CAF50) - Product C: 18 squares spanning rows 8-9 plus 8 squares in row 10 (18%)
• Orange/Coral (#FF7043) - Product D: 12 squares completing the bottom row (12%)

The legend on the right clearly shows all four categories with their percentages: "Product A (42%)", "Product B (28%)", "Product C (18%)", "Product D (12%)". The squares have a slight gap between them (0.9 width/height), creating visual separation. The chart uses a clean void theme with no axes visible. Overall layout is well-balanced with the grid centered and the legend properly positioned.

Quality Score: 95/100

Criteria Checklist

Spec Compliance (35 pts) - 35/35

• SC-01: Correct plot type (10) - Waffle chart with 10×10 grid ✓
• SC-02: Data mapped correctly (7) - Values correctly sum to 100%, each square = 1% ✓
• SC-03: Required features present (7) - Grid layout, color-coded categories, percentages shown ✓
• SC-04: Data range appropriate (4) - All 100 squares visible, values sum correctly ✓
• SC-05: Legend accuracy (4) - Legend shows all 4 categories with correct percentages ✓
• SC-06: Title format (3) - Uses correct format "waffle-basic · letsplot · pyplots.ai" ✓

Visual Quality (35 pts) - 32/35

• VQ-01: Meaningful axis labels (7) - N/A for waffle charts, correctly uses theme_void() ✓
• VQ-02: No overlapping text (6) - All text is clear and readable ✓
• VQ-03: Color choice (5) - Uses Python Blue first, other colors are distinct and colorblind-safe ✓
• VQ-04: Element clarity (5) - Squares are clearly visible with good sizing ✓
• VQ-05: Layout balance (5) - Well-centered grid with good proportions ✓
• VQ-06: Grid subtlety (3) - N/A (waffle chart IS the grid) ✓
• VQ-07: Legend placement (2) - Legend is positioned on the right, doesn't obscure data ✓
• VQ-08: Image size (2) - Scaled to 4800×2700 via scale=3 on 1600×900 base ✓ (-3 minor: actual output may vary based on scaling)

Data Quality (15 pts) - 15/15

• DQ-01: Feature coverage (6) - Shows 4 distinct categories with varying proportions (42%, 28%, 18%, 12%) demonstrating unequal distribution ✓
• DQ-02: Realistic context (5) - Market share scenario is plausible and commonly used ✓
• DQ-03: Appropriate scale (4) - Values sum to 100%, reasonable distribution of percentages ✓

Code Quality (15 pts) - 13/15

• CQ-01: KISS structure (4) - Sequential flow: imports → data → grid building → plot → save ✓
• CQ-02: Reproducibility (3) - Deterministic data (fixed category values) ✓
• CQ-03: Library idioms (3) - Proper use of ggplot grammar, geom_tile, scale_fill_manual ✓
• CQ-04: Clean imports (2) - All imports are used, proper module imports ✓
• CQ-05: Helpful comments (1) - Comments explain grid building logic and color choices ✓
• CQ-06: No deprecated API (1) - Uses current lets-plot API ✓
• CQ-07: Output correct (1) - Saves as plot.png and plot.html ✓
• (-2): Minor: strict=True in zip() is Python 3.10+ syntax but acceptable; ggsave import could be from lets_plot.export

Issues Found

1. Minor - Import style: The ggsave import is correctly from lets_plot.export, which is good practice.
2. Minor - Grid building: The grid building logic is slightly complex but well-commented, making it understandable.

AI Feedback

Excellent implementation! The waffle chart correctly represents proportional data using a 10×10 grid where each square represents 1%. The code smartly preserves category order for the legend and includes percentages in legend labels for clarity. The color palette starts with Python Blue as required and uses colorblind-friendly additional colors. The grid-building algorithm correctly fills from top-left going row by row. The use of coord_fixed(ratio=1) ensures squares remain square. Both PNG and HTML outputs are generated as expected for interactive libraries.

Verdict: APPROVED