v0.5.0 release

[Psy-Fer]

[0.5.0] — 2026-08-07

Added

• PDF backend migrated from svg2pdf to krilla/krilla-svg, plus multi-page output — svg2pdf was archived upstream by its own maintainer as unmaintained, recommending krilla/krilla-svg (same author, used by Typst) as the successor. PdfBackend::render_scenes(&[Scene]) and the one-shot render_to_pdf_multi(pages) render one kuva canvas per PDF page into a single document (like R's pdf() device, e.g. for fgbio/Picard-style reports); nothing is rasterized. By default each page takes its scene's natural size; PdfBackend::with_page_size(PageSize::inches(11.0, 8.5)) instead coerces every page to a fixed size, scaling each scene proportionally to fit and centering it, with the scene's own background color filling the letterbox margin. The pdf feature now requires Rust >= 1.92 (krilla's MSRV) — higher than kuva's own crate-level rust-version (kept at 1.87 deliberately; see README.md's note on why), tracked separately as [package.metadata.msrv] pdf_feature in Cargo.toml. CI's msrv job now builds cli,png,embed_font (not cli,full) against rust-version, plus a new pdf-msrv job that builds cli,full against pdf_feature specifically — the pre-existing msrv job would otherwise have silently asserted a false claim (that full builds at 1.87) forever, since nothing else exercises that combination at the older toolchain. PdfBackend is no longer a zero-sized unit struct usable as a bare value (PdfBackend.render_scene(...)) — use PdfBackend::new().
• kuva twin-y CLI subcommand — dual-axis plot from the command line: two series sharing an x-axis but with independent primary (left) and secondary (right) y-scales, e.g. temperature vs. rainfall. Supports line and scatter as the plot type on either axis (--primary-type/--secondary-type); per-side color and legend label flags; new shared --y2-label/--y2-min/--y2-max/--log-y2/--y2-tick-format flags. Closes CLI: Add twin y-plots #106.
• Layout::with_y2_axis_min/with_y2_axis_max — unconditional secondary-Y-axis bound overrides, mirroring with_y_axis_min/with_y_axis_max. Found needed while building the twin-y CLI: the existing with_y2_range still gets nice-rounded and capped near the secondary plots' own data (the same path the auto-computed range takes), so a requested bound far from the data was largely ignored.
• CLI date/time X axis (--x-date-format, --x-date-unit, --x-date-tick-format, --x-date-tick-step) on scatter and line — parses the X column as a date/time using a strftime-style format instead of a plain number, then ticks it with a DateTimeAxis (auto-selected unit/format by default, or an explicit unit with a sensible default tick format, overridable). Closes CLI: Add date/time axes #107.
• Layout::with_label_background — a semi-opaque background rect behind in-fill value labels (Treemap, Sunburst, Mosaic, Funnel, Gantt), for readability over busy fills or BW-mode hatch patterns. Off by default in color mode; on automatically in BW mode; overridable either way. CLI: --label-background. Closes label backgrounds #102.
• Layout::with_subtitle — render a secondary line centred under the title for a one-line data summary (e.g. n = 1,234 cells). Sized at round(0.7 × title_size) by default or set explicitly with with_subtitle_size; coloured by muting the title colour toward the background so it adapts to light and dark themes rather than a fixed grey; word-wrapped independently of the title via with_subtitle_wrap. The title block reserves the extra height automatically so the plot is pushed down rather than overlapped. CLI: --subtitle and --subtitle-wrap on every subcommand. See Reference → Layout.
• ParetoPlot — bar chart of category values, sorted descending by default, with a superimposed cumulative-percentage line on a secondary axis (fixed 0-100%, the "80/20 rule" chart). Optional dashed threshold reference line (default 80%, labeled with its percentage) and per-point cumulative-percentage labels. Legend shown by default ("Value" / "Cumulative %"). Secondary-axis ticks are formatted as percentages (0%, 20%, …). Categorical axis defaults to rotated (-45°), collision-thinned labels. .with_max_categories(n) collapses a long tail of small categories into one stacked "Other" bar, decoded via per-segment legend entries, instead of cluttering the axis. .with_horizontal(bool) puts categories on Y and values on X. CLI: kuva pareto.
• Secondary X-axis (Layout::with_x2_range/with_x2_label/with_log_x2/with_x2_tick_format, ComputedLayout::map_x2) — a top-drawn counterpart to the existing secondary Y-axis (right side), for plots whose secondary encoding pairs with the value axis rather than the category axis (used by horizontal ParetoPlot). Third-party plot types can use it directly via the same Layout/ComputedLayout fields.
• CLI --header flag — forces the first row to be treated as a header even when it looks like data, the explicit counterpart to the existing --no-header. The two are mutually exclusive. Useful for inputs whose column names are all-numeric (e.g. years). Ignored, with a warning, for parquet input (self-describing). Part of CLI: first line as a header #111.

Fixed

• CLI header auto-detection missed a header masked by a leading numeric column (#111) — the detector only checked whether the first field of the first row was non-numeric, so an input like 5,data over 0,1 / 1,2 treated the header row as data and failed with cannot parse 'data' as a number. Detection now also flags a header when any column holds a non-numeric label atop an otherwise all-numeric column. The rule is a strict superset of the old first-cell check, so existing detections are unchanged; genuinely ambiguous inputs are covered by the new --header / existing --no-header overrides.
• examples/all_plots_simple.rs/all_plots_complex.rs (the "every plot type in one figure" gallery assets) were missing ParetoPlot, BandPlot, and LegendPlot — Replaced some plot repeats to include missing plot types.
• man/kuva.1 was missing the twin-y subcommand — regenerated (kuva man > man/kuva.1).
• Scatter3D/Surface3D instances combined in one panel now share one 3D coordinate box — each instance previously called data_ranges()/drew its own wireframe box independently, so two Scatter3D (or a mix with Surface3D) in the same render_multiple call each normalized to their own min/max and could project completely different data onto identical screen coordinates, with the box itself drawn twice. render_multiple now computes one merged DataRanges3D and draws the box once, shared by every 3D instance in the call.
• Twin-Y x-axis no longer clips a secondary series that extends further than the primary series — Layout::auto_from_twin_y_plots's with_y2_auto unioned the padded x-range across primary and secondary, but left data_x_range (the raw extent used by the axis-range capping added for #98) pinned to primary's range alone. When the capped branch triggered, the x-axis max was computed from primary's raw max instead of the true combined max, rounding the axis short and clipping secondary's data past that point. data_x_range is now unioned across both series.

Security

• Data-derived text (group names, legend/category labels) is now XML-escaped before being written into SVG attribute values (e.g. data-group="...", data-x="...") in interactive-mode output. Previously these were interpolated raw, so a crafted data file's label could break out of the attribute and inject arbitrary markup (a stored-XSS-style issue) into the rendered SVG. Fixed at every extra_attrs call site in src/render/render.rs via a new render_utils::escape_attr.
• Arbitrary/unrecognized color strings (Color::Css, e.g. an unrecognized --color-by value) are now XML-escaped when written into fill/stroke attributes, and stroke-dasharray, root font-family/fill, and the background-rect fill in the SVG backend are now escaped as well, closing the same class of attribute-breakout issue for CSS-derived values.
• --terminal output now filters control characters (ESC, C0/C1, DEL) out of data-derived labels before they reach the character grid, replacing them with U+FFFD. Previously a label containing a raw escape sequence (e.g. from an untrusted data file) could be replayed into the operator's real terminal when the rendered grid was printed, potentially triggering an ANSI/OSC-based terminal escape injection.

Reported via private disclosure (GHSA-3c48-9r95-hqhr). See the advisory for full details once published.