[FIX] Report figures: consistent fonts via figsize↔slot, smaller files, paginated multipanels, clock ±30 / stage1

[eleanorfrajka]

Summary

Report figures had small, inconsistent fonts and large files because there was no mapping between a figure's rendered width and its display slot: figures were drawn at arbitrary 12–14 in widths, then CSS capped them to max-width:50%/33%, so a half-slot figure downscaled ~0.43 (not the intended ~0.80) and a 12 pt label showed at ~8 px. This branch introduces a figsize↔slot convention so one font.size renders at one on-screen size everywhere, cuts figure bytes with palette-quantized PNGs, paginates tall multipanel figures so they stop overflowing PDF pages, and fixes several specific figure bugs (clock-alignment window, start/end window data source). It also removes one piece of dead plotting code.

Figure sizing and fonts

Added slot-width constants to oceanarray/config/parameters.py — W_FULL=9.0, W_TWOTHIRDS=6.0, W_HALF=4.5, W_THIRD=3.0 (inches; width only, height stays content-driven). Every figure now sets its width from the constant matching its CSS display slot, so display_px / png_in is constant across the report and fonts are consistent at every slot.

Swept ~24 hardcoded figsize= values across plotters/current.py, ts.py, spectrum.py, primitives.py, hydrography.py and diagnostic.py onto the slot constants, and removed scattered per-figure fontsize= overrides so the mplstyle governs type size.

Updated oceanarray/oceanarray.mplstyle to a single consistent type scale — axes.titlesize 12, axes.labelsize/xtick/ytick 10, font.size 10, legend.fontsize 9 — plus axes.linewidth 0.6 and explicit grid/contour line settings.

savefig.dpi: 150 is retained in the mplstyle as the single source of truth for figure dpi, and the previous REPORT_FIG_DPI = 110 override in _fig_to_base64 (which silently shadowed it — figures were rendering at 110, not 150) is gone. dpi is a size/crispness knob only; displayed font size is set by the figsize↔slot ratio and is dpi-independent.

Smaller figure files

_fig_to_base64 now composites each figure onto white and quantizes it to a 256-colour palette PNG. Report figures are few-colour by construction (line art plus discrete colorbars, which the project already mandates), so indexed PNG is ~visually lossless here and cuts figure bytes roughly 3×, the dominant lever on report and PDF size. Adds an explicit pillow>=9.0 entry to requirements.txt (matplotlib already pulls it in).

Paginated multipanel figures (report-figures #3 / #10)

Tall instrument figures were overflowing PDF pages (a single <img> cannot split across pages). _build_fig_from_ds now accepts a panels= subset; _make_instrument_fig returns a list of base64 PNGs, chunking panels into images of at most _MAX_TS_PANELS (5) each, and the instrument template loops over them. Per-panel height dropped 3.0 → 2.0 so a 5-panel image fits one page without vertical squish.

The same treatment was applied to the start/end windows figure: draw_windows gained a panels= subset arg and now renders at W_FULL with per-panel height 2.0; _make_windows_fig returns a paginated list; the template loops. Each row is a half-width "First 6 h" panel beside a half-width "Last 6 h" panel.

The img.fig { max-height: 22cm } print cap remains as a backstop for any figure that still exceeds a page.

Clock-alignment check (report-figures #4)

plot_clock_offset_check now centres its zoom windows on the deployment and recovery times (±30 min, was 10), and normalises each plotted instrument trace over the plotted window as (x − mean) / std so traces of different amplitude overlay comparably; the y-axis is labelled in standard deviations. The Tier-3 wrapper _make_clock_check_b64 default was corrected from 10 to 30 (it had been shadowing the plotter default).

Start/end windows use stage-1 data

MooringReport._clock_nc_paths and the windows figure now prefer the untrimmed _stage1.nc over stage2/3, falling back only if stage1 is absent. stage2/3 are trimmed to the deployment window, which removes exactly the pre-deploy / post-recover data the ±window check needs to show the deployment/recovery transient; raw clocks also expose the real inter-instrument offsets before correction.

Dead code removal

Removed draw_isopycnal_fig (an unwired time × pressure iso-sigma contour figure with no call site) together with its Tier-3 wrapper _make_isopycnal_fig_b64, the now-orphaned filter_sigma_tukey and pressure_axis imports, its three plotters/__init__.py export references, and stale migration notes in spectrum.py. The grid report's "Isopycnal height above seabed" section is unaffected — it is drawn by the separate, still-wired draw_isopycnal_ts_fig.

Testing

Full suite: 739 passed, 4 skipped. ruff check and ruff format clean. test_plot_guard.py updated so _make_instrument_fig and _make_windows_fig assert a non-empty list (they now paginate). Rendered the dune2 fixture to HTML + combined PDF and visually verified pagination, half-width window columns, and figure crispness.

Breaking changes

oceanarray.plotters.draw_isopycnal_fig removed. It was exported in plotters.__all__ but was dead code with no call site. Migration: none required; nothing called it. The wired isopycnal figure draw_isopycnal_ts_fig is unchanged.

Report HTML output changes shape: the instrument time-series and start/end-windows sections now emit one or more <img> per section (paginated) rather than a single image. Anything that scraped a fixed single figure per section must handle a list.