[pie-basic] letsplot implementation

[github-actions]

[pie-basic] letsplot Implementation

Parent Issue: #206
Spec: specs/pie-basic.md
Library: letsplot
Feature Branch: plot/pie-basic

---

Attempt History

Attempts will be documented below as comments.

[github-actions]

Attempt 1/3

Technical Approach

• Imports: import pandas as pd, from lets_plot import (
• Plot function: ggplot
• Config: color=white

Status

• PR: feat(letsplot): implement pie-basic #377
• File: plots/letsplot/pie/pie-basic/default.py
• Workflow: 19995639840

---

[github-actions]

🧪 Test Results (PR #377)

Python:

📊 Plot Preview (Python 3.13)

letsplot (default) - NEW

---

🤖 Generated by gen-preview workflow

[claude]

AI Review - Attempt 1/3

Quality Evaluation

Evaluator	Score	Verdict
Claude	88/100	approve

Criteria Checklist

Visual Quality

• [N/A] VQ-001: Axes labeled correctly — Pie charts don't use axes
• VQ-002: Visual clarity — Clean design with theme_void(), no distracting elements
• VQ-003: Elements clear — Pie slices are clearly visible with good size, white stroke separates segments well
• VQ-004: No overlap — Legend positioned on right, no overlap with chart, text readable
• VQ-005: Legend present — Legend shows all 5 categories with correct color mapping
• VQ-006: Colorblind safe — Uses PyPlots.ai palette (blue, yellow, red, green, violet) - mostly safe, no pure red-green adjacent
• VQ-007: Image size — Correct 4800 × 2700 px (1600×900 scaled 3x)
• VQ-008: Title — "Market Share Distribution" is centered and clear

Code Quality

• [N/A] CQ-001: Type hints — Plot implementations follow KISS style (no functions)
• [N/A] CQ-002: Docstring — Plot implementations follow KISS style (no functions)
• [N/A] CQ-003: Input validation — Plot implementations use hardcoded example data per spec
• [N/A] CQ-004: Clear error messages — N/A for simple scripts
• CQ-005: No magic numbers — Colors defined in named constant PYPLOTS_COLORS

Correctness

• CR-001: Data accurate — Uses correct category/value columns from spec example
• CR-002: Spec compliance — Shows 5 categories with correct proportions (35, 25, 20, 15, 5)
• [N/A] CR-003: Edge cases — N/A for example scripts with fixed data

Issues Found

None critical. Minor observations:

1. The pie chart appears relatively small compared to the canvas size, but this is acceptable as it maintains clean proportions with the legend

Strengths

1. Clean implementation using geom_pie() with stat="identity" for pre-computed values
2. Proper use of theme_void() for pie charts (removes unnecessary axes)
3. White stroke between slices improves readability
4. Legend properly positioned and styled
5. Follows lets-plot library conventions correctly
6. Correct output dimensions (4800×2700px)

AI Feedback for Next Attempt

No changes needed - implementation meets all requirements

Verdict: APPROVED

The lets-plot implementation correctly creates a basic pie chart matching the specification. The code follows the KISS style guidelines, uses appropriate lets-plot idioms (geom_pie, theme_void), and produces a clear, professional visualization.