djrhails-graphs 0.8.0

Economist-style chart theme for matplotlib/seaborn

graphs

Economist-style chart theme for matplotlib and seaborn — global theme, title-stack finaliser with renderer-measured wrapping, on-grid axis labels, direct line labels, CI bands, and a catalogue of chart helpers (bars, dumbbells, thermometers, bump charts, lollipops). IBM Plex Sans typography and a curated palette.

Install

pip install djrhails-graphs

PyPI distribution is djrhails-graphs because the bare name graphs is taken. The import package is graphs.

Quick start

import matplotlib.pyplot as plt
import numpy as np

from graphs import finalize, label_lines, save_chart, set_theme, subplots

set_theme()

x = np.arange(12)
fig, ax = subplots("wide")
ax.plot(x, 40 + 2.1 * x, label="Series A")
ax.plot(x, 58 - 1.3 * x, label="Series B")
label_lines(ax)
finalize(
    ax,
    title="State the finding, not the topic",
    descriptor="Country, metric, unit",
    source="Source: Organisation",
)
save_chart(__file__)

finalize() does the heavy lifting: auto-sized margins, title stack with the delta marker (titles auto-wrap to the figure width), numeric y labels seated on gridlines that extend under them, source line, right-hand y-axis.

SKILL.md is the full manual — design principles, headline conventions, the complete API table, and a when-to-use index of 39 worked examples in examples/.

Palette

from graphs import PALETTE, colors, C_RED, C_RED_BRAND, C_SPINE, C_GRID, C_LABEL

Nine named colours in PALETTE (red-led default cycle); structural greys for spines/grid/labels/source; cycle_for(chart_type) for per-chart-type orders.

Typography

IBM Plex Sans (headlines) and IBM Plex Sans Condensed (everything else) are loaded automatically. If already registered in matplotlib's font manager, no download occurs. Otherwise TTFs are fetched from github.com/IBM/plex on first use and cached inside the installed package.

Fallback chain: IBM Plex Sans Condensed → IBM Plex Sans → Verdana → Arial → DejaVu Sans.

Development

Hot reload during chart iteration:

uv run graphs-watch

Watches graphs/ and examples/ for .py changes and re-renders the affected examples + the comparison strip in parallel. The watcher routes by path:

• graphs/**/*.py or examples/_data.py → regen all examples + comparisons
• examples/build_comparisons.py → comparisons only
• examples/<name>.py → that one example + comparisons

Comparison harness

examples/build_comparisons.py composes side-by-side images for visual review:

• url-kind entries download a Medium-hosted PNG and stack it above our replica (used for the "Mistakes, we've drawn a few" redesigns).
• local_ref-kind entries use a local reference image (e.g. the styleguide page for the thermometer chart).

Generated comparisons land in examples/comparisons/<name>.png (gitignored — the reference images aren't ours to redistribute).

examples/fetch_refs.py populates examples/comparisons/_originals/ for the daily-chart replicas: it downloads the Economist "2019 daily charts" grid and cuts it into per-chart reference cells (rows are located via the red Economist tag that tops every chart — blank-gap heuristics misfire on detached titles/footnotes).

CSVs fetched at runtime by example scripts are cached under examples/.data/ via examples/_data.py::load_csv_text(url).

License

MIT. See LICENSE.