bencher.sparkline

Inline-SVG sparklines for benchmark trend series.

A sparkline compresses a metric’s over-time series_for_var() (per-event mean with a ±std noise band) into a tiny inline SVG, so both the trend and the run-to-run spread are visible at a glance without opening a full report. The output is pure numeric geometry — no caller strings are interpolated — so it is safe to embed unescaped.

Functions

sparkline_svg(→ str)

Return an inline SVG sparkline: ±std band, mean line, a node per run.

Module Contents

bencher.sparkline.sparkline_svg(means: list[float | None], stds: list[float | None], *, width: int = 120, height: int = 28, pad: int = 3) → str

Return an inline SVG sparkline: ±std band, mean line, a node per run.

Pure-numeric input (no caller strings interpolated), so the output is safe to render unescaped. Auto-scales to the band extent; degenerates gracefully to a single node when only one finite point exists, and to an empty <svg> when none do.

The SVG carries a viewBox and preserveAspectRatio="none" so CSS can stretch it to whatever width its container ends up at. vector-effect keeps the line/band stroke crisp under that non-uniform scaling.

A small node marks every event on the line so the eye can see where the individual runs sit; nodes are drawn identically (the latest is simply the rightmost) and the sparkline itself stays uncolored — the caller (e.g. a cell background) owns any verdict color.

With more than one point, a narrow right-margin column collapses every run’s mean onto the (shared) value axis as identical alpha-blended dots, so value regions where runs cluster read darker — surfacing the run-to-run spread, and any bimodality, that the mean line alone hides.

means is the trend and drives the x-axis; stds is the noise band and is paired positionally. The two are zipped with itertools.zip_longest() so a length mismatch degrades gracefully rather than silently dropping trailing points: a missing std collapses that point’s band to zero, and a surplus std (no matching mean) is ignored.