feat(bokeh): implement spectrum-basic

[github-actions]

Implementation: spectrum-basic - bokeh

Implements the bokeh version of spectrum-basic.

File: plots/spectrum-basic/implementations/bokeh.py

Parent Issue: #2926

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🤖 impl-generate workflow

[claude]

AI Review - Attempt 1/3

Image Description

The plot displays a frequency spectrum with amplitude (dB) on the Y-axis ranging from approximately -80 to 0, and frequency (Hz) on the X-axis from 0 to 500 Hz. The main data is shown as a blue line (#306998) with a subtle light blue fill underneath. Three prominent peaks are clearly visible at 50 Hz, 150 Hz, and 400 Hz, marked with yellow/gold circle markers (#FFD43B) and dashed vertical lines extending down to -80 dB. The title "spectrum-basic · bokeh · pyplots.ai" appears in the top-left. A legend in the top-right shows "Signal Spectrum" and the three peak frequencies. The background is a light off-white (#fafafa) with dashed grid lines. The noise floor is visible around -60 to -70 dB with typical FFT variation.

Quality Score: 92/100

Criteria Checklist

Visual Quality (37/40 pts)

• VQ-01: Text Legibility (10/10) - Title at 36pt, axis labels at 28pt, tick labels at 20pt - all clearly readable
• VQ-02: No Overlap (8/8) - No overlapping text elements, legend is well-positioned
• VQ-03: Element Visibility (8/8) - Line width of 4 is excellent for the canvas size, peaks clearly marked with large circle markers (size=25)
• VQ-04: Color Accessibility (5/5) - Blue (#306998) and yellow (#FFD43B) provide excellent contrast and are colorblind-safe
• VQ-05: Layout Balance (4/5) - Good utilization of canvas, slight excess whitespace on right side
• VQ-06: Axis Labels (2/2) - Both axes have descriptive labels with units: "Frequency (Hz)" and "Amplitude (dB)"
• VQ-07: Grid & Legend (0/2) - Legend labels are too small/hard to read at full resolution, legend items appear cramped

Spec Compliance (25/25 pts)

• SC-01: Plot Type (8/8) - Correct frequency spectrum plot
• SC-02: Data Mapping (5/5) - Frequency on X-axis, amplitude in dB on Y-axis
• SC-03: Required Features (5/5) - Multiple frequency components shown, peak highlighting present, dB scale used
• SC-04: Data Range (3/3) - Axes show full data range (0-500 Hz, -80 to 0 dB)
• SC-05: Legend Accuracy (2/2) - Legend correctly identifies signal spectrum and peak frequencies
• SC-06: Title Format (2/2) - Correct format: "spectrum-basic · bokeh · pyplots.ai"

Data Quality (18/20 pts)

• DQ-01: Feature Coverage (8/8) - Shows fundamental frequency (50 Hz), harmonic (150 Hz), separate component (400 Hz), and noise floor - excellent demonstration of spectrum analysis
• DQ-02: Realistic Context (5/7) - Synthetic signal is plausible but generic; could be more specific (e.g., "motor vibration" or "audio signal")
• DQ-03: Appropriate Scale (5/5) - Realistic frequency range (0-500 Hz), appropriate sample rate (8192 Hz), sensible dB scale

Code Quality (9/10 pts)

• CQ-01: KISS Structure (3/3) - Clean linear structure: imports → data → plot → save
• CQ-02: Reproducibility (3/3) - np.random.seed(42) is set
• CQ-03: Clean Imports (2/2) - Only necessary imports used
• CQ-04: No Deprecated API (1/1) - Uses current Bokeh API
• CQ-05: Output Correct (0/1) - Saves both PNG and HTML, but code structure is correct

Library Features (3/5 pts)

• LF-01: Uses distinctive library features (3/5) - Uses ColumnDataSource, varea for fill, interactive tools, but could leverage more Bokeh-specific features like HoverTool for frequency/amplitude display

Strengths

• Excellent visual clarity with proper text sizing for the 4800x2700 canvas
• Clear peak highlighting with dashed vertical lines and circle markers at 50 Hz, 150 Hz, and 400 Hz
• Good use of varea for the subtle fill under the curve which aids visual interpretation
• Proper FFT implementation with correct normalization and dB conversion
• Colorblind-safe color scheme with good contrast

Weaknesses

• Legend text appears small relative to the canvas size; could benefit from larger legend text
• Missing HoverTool which would showcase Bokeh's interactivity for showing exact frequency/amplitude values

Verdict: APPROVED