feat(letsplot): implement point-and-figure-basic

[github-actions]

Implementation: point-and-figure-basic - letsplot

Implements the letsplot version of point-and-figure-basic.

File: plots/point-and-figure-basic/implementations/letsplot.py

Parent Issue: #3755

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🤖 impl-generate workflow

[claude]

AI Review - Attempt 1/3

Image Description

The plot displays a Point and Figure (P&F) chart with green X symbols representing rising price columns (bullish) and red O symbols representing falling price columns (bearish). The chart shows price movement from approximately $80 to $155 across 23 columns (reversal numbers 0-22). The X-axis is labeled "Column (Reversal Number)" and Y-axis is labeled "Price ($)". The title correctly displays "point-and-figure-basic · letsplot · pyplots.ai". The chart demonstrates clear alternating columns of X's and O's with appropriate spacing, showing multiple trends including uptrends and downtrends. The overall layout is clean with a minimal theme, subtle horizontal grid lines, and no legend (appropriately hidden since color coding is self-explanatory).

Quality Score: 91/100

Criteria Checklist

Visual Quality (36/40 pts)

• VQ-01: Text Legibility (10/10) - Title, axis labels, and tick marks are all clearly readable at full size
• VQ-02: No Overlap (8/8) - No overlapping text or symbols
• VQ-03: Element Visibility (6/8) - X and O symbols are visible and appropriately sized, though could be slightly bolder
• VQ-04: Color Accessibility (5/5) - Green (#16a34a) and red (#dc2626) are distinguishable, and the X vs O shape difference provides secondary distinction
• VQ-05: Layout Balance (5/5) - Good use of canvas space, plot fills majority of area with balanced margins
• VQ-06: Axis Labels (2/2) - "Price ($)" and "Column (Reversal Number)" are descriptive with units
• VQ-07: Grid & Legend (0/2) - Legend hidden (appropriate), but vertical grid lines are disabled which is correct for P&F, though horizontal grid could be more subtle

Spec Compliance (25/25 pts)

• SC-01: Plot Type (8/8) - Correct Point and Figure chart with X and O columns
• SC-02: Data Mapping (5/5) - Columns represent reversals, Y-axis shows price levels
• SC-03: Required Features (5/5) - Uses X for rising, O for falling, green for bullish, red for bearish, 3-box reversal
• SC-04: Data Range (3/3) - Full price range visible from ~$80 to ~$155
• SC-05: Legend Accuracy (2/2) - No legend needed, color/symbol mapping is standard P&F convention
• SC-06: Title Format (2/2) - Correctly formatted as "point-and-figure-basic · letsplot · pyplots.ai"

Data Quality (18/20 pts)

• DQ-01: Feature Coverage (7/8) - Shows both uptrends and downtrends, multiple reversals, but could show more distinct support/resistance patterns
• DQ-02: Realistic Context (7/7) - Stock price simulation with realistic price movements and trends
• DQ-03: Appropriate Scale (4/5) - Price range $80-155 is realistic for stocks, box size of $2 is appropriate

Code Quality (9/10 pts)

• CQ-01: KISS Structure (3/3) - Linear flow: imports → data generation → P&F algorithm → plot → save
• CQ-02: Reproducibility (3/3) - Uses np.random.seed(42)
• CQ-03: Clean Imports (2/2) - All imports are used
• CQ-04: No Deprecated API (1/1) - Uses current lets-plot API
• CQ-05: Output Correct (0/1) - Saves to "plot.png" but path="." is explicit

Library Features (3/5 pts)

• LF-01: Uses geom_text for symbol rendering, ggplot grammar, theme customization, and ggsave with scale parameter for high-res export

Strengths

• Excellent implementation of the P&F algorithm with correct box size and 3-box reversal logic
• Clean use of lets-plot's ggplot2-style grammar with appropriate aesthetics mapping
• Perfect title format and axis labeling with descriptive names and units
• Good color choices with green/red that also include shape distinction (X/O) for accessibility
• Proper handling of column-based (not time-based) X-axis which is key to P&F charts
• High-resolution export with scale=3 for 4800x2700 output

Weaknesses

• Grid styling could be improved - horizontal grid is visible but could use more subtle alpha
• The X and O symbols could be slightly larger/bolder for better visual impact at the target resolution
• Spec mentions adding support/resistance trend lines which are not implemented (optional per spec)

Verdict: APPROVED