feat(pygal): implement pie-drilldown

[github-actions]

Implementation: pie-drilldown - pygal

Implements the pygal version of pie-drilldown.

File: plots/pie-drilldown/implementations/pygal.py

Parent Issue: #3072

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🤖 impl-generate workflow

[claude]

AI Review - Attempt 1/3

Image Description

The plot displays a donut chart (pie chart with inner radius of ~35%) showing a company budget allocation across four main departments. The largest slice is Engineering at $450,000 (blue), followed by Marketing at $280,000 (yellow), Operations at $180,000 (darker blue), and Human Resources at $90,000 (green/sage). The title reads "Company Budget · pie-drilldown · pygal · pyplots.ai" at the top. Below the chart is a subtitle "All Departments | Click slice to drill down" and a legend at the bottom listing all four departments. Dollar values are displayed on each slice. The chart uses a clean white background with a square 1:1 aspect ratio.

Quality Score: 82/100

Criteria Checklist

Visual Quality (32/40 pts)

• VQ-01: Text Legibility (8/10) - Title and labels readable, values on slices visible but category names on slices are quite small
• VQ-02: No Overlap (8/8) - No overlapping text elements
• VQ-03: Element Visibility (7/8) - Slices well-sized for data, donut provides good visual
• VQ-04: Color Accessibility (4/5) - Colors distinguishable, some similarity between the two blue shades
• VQ-05: Layout Balance (3/5) - Good chart size but legend is quite far from plot
• VQ-06: Axis Labels (N/A for pie) - Using subtitle for context (1/2)
• VQ-07: Grid & Legend (1/2) - Legend at bottom but small text

Spec Compliance (20/25 pts)

• SC-01: Plot Type (8/8) - Correct pie/donut chart type
• SC-02: Data Mapping (5/5) - Hierarchical data correctly structured
• SC-03: Required Features (2/5) - Missing: animated transitions, clickable breadcrumbs in PNG (only in HTML), no percentage labels on PNG slices
• SC-04: Data Range (3/3) - All departments shown with complete values
• SC-05: Legend Accuracy (2/2) - Legend correctly matches data
• SC-06: Title Format (0/2) - Missing spec-id format; title shows "Company Budget" but should lead with "pie-drilldown · pygal · pyplots.ai"

Data Quality (18/20 pts)

• DQ-01: Feature Coverage (7/8) - Shows hierarchical data with 2 levels, but PNG only shows top level
• DQ-02: Realistic Context (7/7) - Company budget is an excellent real-world scenario
• DQ-03: Appropriate Scale (4/5) - Values are realistic for departmental budgets

Code Quality (9/10 pts)

• CQ-01: KISS Structure (3/3) - Clean imports → data → plot → save structure
• CQ-02: Reproducibility (3/3) - Deterministic data (no random)
• CQ-03: Clean Imports (2/2) - Only pygal and Style imported
• CQ-04: No Deprecated API (1/1) - Current pygal API used
• CQ-05: Output Correct (0/1) - Saves plot.png AND plot.html (correct)

Library Features (3/5 pts)

• LF-01: Uses distinctive library features (3/5) - Uses pygal's inner_radius for donut, value_formatter, legend_at_bottom. Good usage but HTML uses Chart.js instead of pygal for interactivity.

Strengths

• Clean hierarchical data structure with realistic company budget scenario
• Good use of pygal's donut chart (inner_radius) for visual appeal
• Value formatting with currency ($) on slices
• Subtitle provides navigation hint for drilldown concept
• HTML version implements full drilldown with breadcrumb navigation
• Colorblind-friendly color palette

Weaknesses

• Title format incorrect: should be "{spec-id} · {library} · pyplots.ai" but shows "Company Budget · pie-drilldown · pygal · pyplots.ai"
• PNG static image cannot demonstrate drilldown interactivity (core spec feature)
• HTML version uses Chart.js instead of pygal's native SVG interactivity
• No percentage labels shown alongside dollar values on slices
• Legend text appears small relative to the large canvas size
• The two blue colors (Engineering and Operations) are somewhat similar

Verdict: REJECTED

Rationale: While the implementation shows good understanding of the drilldown concept and provides an excellent HTML version with full interactivity, the core issue is that the HTML uses Chart.js rather than pygal for the interactive component. The title format is also incorrect (should start with spec-id). The PNG image alone cannot demonstrate the drilldown feature which is central to this specification.

[github-actions]

🔧 Repair Attempt 1/3

Applied fixes based on AI review feedback.

Status: Repair completed, re-triggering review...

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🤖 impl-repair

[claude]

AI Review - Attempt 2/3

Image Description

The plot displays a donut pie chart (ring chart with inner_radius=0.35) showing a company budget breakdown across 4 departments. The chart uses distinct colors: muted blue for Engineering ($450,000), yellow for Marketing ($280,000), coral/orange for Operations ($180,000), and sage green for Human Resources ($90,000). The title "Company Budget · pie-drilldown · pygal · pyplots.ai" appears at the top, with a subtitle "All Departments | Click slice to drill down" at the bottom. A legend at the bottom displays all department names with color-coded boxes. Dollar values are displayed on each slice. The chart occupies a good portion of the 3600×3600 square canvas with balanced margins.

Quality Score: 90/100

Criteria Checklist

Visual Quality (36/40 pts)

• VQ-01: Text Legibility (8/10) - Title and values readable, but slice labels showing category names are quite small
• VQ-02: No Overlap (8/8) - No overlapping text elements
• VQ-03: Element Visibility (8/8) - Donut chart is well-sized, slices clearly visible
• VQ-04: Color Accessibility (5/5) - Colorblind-friendly palette (blue, yellow, coral, green are distinct)
• VQ-05: Layout Balance (5/5) - Good proportions, chart fills canvas well with balanced margins
• VQ-06: Axis Labels (N/A for pie) - Subtitle serves as context indicator
• VQ-07: Grid & Legend (2/2) - Legend well-placed at bottom, clean presentation

Spec Compliance (22/25 pts)

• SC-01: Plot Type (8/8) - Correct pie/donut chart type for hierarchical drilldown
• SC-02: Data Mapping (5/5) - Values correctly mapped to slice sizes
• SC-03: Required Features (4/5) - Has breadcrumb indicator, values shown; click hint present. PNG is static but HTML has full interactivity (-1 for static preview lacking percentage display mentioned in spec)
• SC-04: Data Range (3/3) - All categories visible
• SC-05: Legend Accuracy (2/2) - Legend labels match data
• SC-06: Title Format (0/2) - Title shows "Company Budget · pie-drilldown · pygal · pyplots.ai" but should be "{spec-id} · {library} · pyplots.ai" format (pie-drilldown · pygal · pyplots.ai)

Data Quality (20/20 pts)

• DQ-01: Feature Coverage (8/8) - Shows hierarchical data with 4 main categories, each having subcategories
• DQ-02: Realistic Context (7/7) - Company budget breakdown is a realistic business scenario
• DQ-03: Appropriate Scale (5/5) - Budget values ($25K-$450K) are plausible for departments

Code Quality (8/10 pts)

• CQ-01: KISS Structure (2/3) - Has helper functions (format_value_with_percent, create_pygal_chart) which are necessary for the drilldown feature
• CQ-02: Reproducibility (3/3) - Deterministic data, no random values
• CQ-03: Clean Imports (2/2) - Only pygal and Style imported
• CQ-04: No Deprecated API (1/1) - Current pygal API
• CQ-05: Output Correct (0/1) - Outputs plot.png and plot.html (correct)

Library Features (4/5 pts)

• LF-01: Uses distinctive library features (4/5) - Uses pygal's SVG rendering, xlink for interactivity, custom Style, inner_radius for donut effect, value_formatter, HTML generation with embedded SVG

Strengths

• Excellent hierarchical data structure with company budget breakdown across departments and sub-categories
• Colorblind-friendly palette with distinct blue, yellow, coral, and green colors
• Full interactive HTML implementation with breadcrumb navigation and drill-down functionality
• Good use of pygal's native SVG capabilities with xlink attributes
• Clean donut chart design with inner_radius creating visual appeal
• Value formatter showing dollar amounts on slices

Weaknesses

• Title format includes "Company Budget" prefix instead of strict "{spec-id} · {library} · pyplots.ai" format
• PNG preview shows only dollar values, not percentages as specified in spec ("Display percentage and value labels on slices")
• Slice category labels appear small relative to the large canvas size

Verdict: APPROVED