feat(highcharts): implement scatter-regression-lowess

[github-actions]

Implementation: scatter-regression-lowess - python/highcharts

Implements the python/highcharts version of scatter-regression-lowess.

File: plots/scatter-regression-lowess/implementations/python/highcharts.py

Parent Issue: #2855

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🤖 impl-generate workflow

[claude]

AI Review - Attempt 1/3

Image Description

Light render (): Scatter plot with 200 green data points (#009E73) on a warm off-white background (#FAF8F1). Title reads "scatter-regression-lowess · highcharts · anyplot.ai" with subtitle "Non-linear Relationship with LOWESS Smoothing". X-axis labeled "Input Variable" (0-10), Y-axis "Output Variable" (-5 to 25). An orange LOWESS regression curve (#D55E00) smoothly traces the non-linear trend showing a U-shaped dip in the middle region and upward trend toward the right. Legend in top-right corner shows "Data Points" and "LOWESS Curve". All text is clearly readable against the light background with dark ink colors. No legibility issues.

Dark render (): Identical plot on warm near-black background (#1A1A17). Data point color remains green (#009E73), LOWESS curve remains orange (#D55E00)—data colors preserved exactly. Text colors are light (light beige/off-white) for legibility on dark background. All text clearly visible: title, axis labels, tick labels, and legend. No dark-on-dark failures. Both renders pass legibility check.

Score: 90/100

Category	Score	Max
Visual Quality	30	30
Design Excellence	12	20
Spec Compliance	15	15
Data Quality	15	15
Code Quality	10	10
Library Mastery	8	10
Total	90	100

Visual Quality (30/30)

• VQ-01: Text Legibility (8/8) - All font sizes explicitly set (title 28px, labels 22px, ticks 18px). Perfectly readable in both themes.
• VQ-02: No Overlap (6/6) - No overlapping text, legend positioned without collision
• VQ-03: Element Visibility (6/6) - 200 markers (radius 8) optimally sized, LOWESS curve (lineWidth 5) clearly distinct
• VQ-04: Color Accessibility (2/2) - Okabe-Ito palette, good contrast, CVD-safe
• VQ-05: Layout & Canvas (4/4) - Plot fills 50-80% of canvas with balanced margins, no cut-off
• VQ-06: Axis Labels & Title (2/2) - Descriptive labels (Input Variable, Output Variable)
• VQ-07: Palette Compliance (2/2) - First series #009E73 ✓, second #D55E00 (Okabe-Ito pos 2) ✓, backgrounds correct, data colors identical across themes

Design Excellence (12/20)

• DE-01: Aesthetic Sophistication (4/8) - Well-configured defaults with intentional colors and typography, professional but relies on library defaults
• DE-02: Visual Refinement (4/6) - Grid styling applied, legend styled with background/border, spacing configured
• DE-03: Data Storytelling (4/6) - Subtitle provides context, orange curve contrasts with green points creating visual hierarchy

Spec Compliance (15/15)

• SC-01: Plot Type (5/5) - Scatter with LOWESS regression curve
• SC-02: Required Features (4/4) - Scatter points, LOWESS curve, non-linear relationship, moderate smoothing (frac=0.3)
• SC-03: Data Mapping (3/3) - X/Y correctly mapped, all data visible
• SC-04: Title & Legend (3/3) - Title format correct, legend labels match data

Data Quality (15/15)

• DQ-01: Feature Coverage (6/6) - Shows non-linear trend, LOWESS adaptation, noise, density variation
• DQ-02: Realistic Context (5/5) - Plausible exploratory scenario, neutral topic, realistic noise
• DQ-03: Appropriate Scale (4/4) - Mathematical relationship sound, value ranges plausible

Code Quality (10/10)

• CQ-01: KISS Structure (3/3) - Linear flow, lowess function justified, no over-engineering
• CQ-02: Reproducibility (2/2) - Random seed set to 42
• CQ-03: Clean Imports (2/2) - All imports used
• CQ-04: Code Elegance (2/2) - LOWESS implementation clean, no fake functionality
• CQ-05: Output & API (1/1) - Saves as plot-{THEME}.png and plot-{THEME}.html, current API

Library Mastery (8/10)

• LM-01: Idiomatic Usage (5/5) - Expertly uses Highcharts Chart, HighchartsOptions, series management, Selenium export
• LM-02: Distinctive Features (3/5) - Uses SplineSeries and marker customization, but mostly generic API usage

Score Caps Applied

• None

Strengths

• Perfect visual quality: all text legible in both themes, no overlap, optimal element sizing
• Full spec compliance: correct plot type, all features present, proper title/legend format
• Excellent data quality: realistic scenario, shows all aspects of plot type
• Clean code: reproducible, well-structured, proper theme adaptation
• Strong Highcharts expertise: idiomatic API usage, correct configuration, working Selenium export

Weaknesses

• Design Excellence is moderate: relies on well-configured library defaults rather than custom design vision
• Library Mastery could leverage more Highcharts-specific features: generic API usage rather than distinctive features

Issues Found

None—implementation is high quality and fully compliant.

Verdict: APPROVED ✅

Score 90/100 exceeds the Attempt 1 threshold of ≥90. Ready for merge. 🚀