chartlet 0.21.0

Breaking

• Topic map and knowledge landscape: the experimental types topicmap and atlas are gone,
  with their blocks, the area picker of the HTML figure, their example files, the stylesheet part
  and their warnings. A specification with either type is refused with invalid_spec.

Added

• Themes: tokens in a specification set single colors of the palette by the name of the
  --chartlet-* custom property without its prefix; they reach the print and social variants and
  PNG. Details: Customize the look.
• Themes: a theme file of your own colors is applied to any number of specifications with
  --theme <name|file>, the theme option of @casoon/chartlet and <Chart>, the theme input
  of chartlet_render and chartlet::apply_theme. light, dark and blueprint ship as such
  files in themes/.
• Themes: a color set in tokens that lies on another with less contrast than WCAG 2.2 asks for is
  reported as low_contrast at the token. Details: Contrast.
• CLI: chartlet stylesheet starts its output with /* generated by chartlet - do not edit */.
  Details: Formatters and linters.
• Schema: chartlet-theme.schema.json for theme files, and tokens in the specification schema.
• Site: the Customize page shows five ways to restyle a chart, each rendered.
• Site: the showcase gains the sequence diagram sign-in-sequence, the architecture diagram
  tenant-architecture and a QR code, the first example of chartlet::qr.

Changed

• Rust: the crate declares rust-version = "1.88", which README and the installation page already
  stated; it builds with that version, with and without png.
• Site: the showcase is grouped by topic with a jump list and shows one example per variant.

Full changelog: https://casoon.github.io/chartlet/changelog/

0.8.0

chartlet 0.8.0

chartlet 0.7.1

Fixes only, from a render sweep across sizes, languages and variants and three code reviews of
0.7.0. Specifications that rendered with 0.7.0 still render, except a declared axis step that
would give more than 50 ticks (or none), which is now refused instead of drawing an unreadable or
endless axis.

Fixed

• A time axis counts the ticks a step actually places instead of estimating them, and spaces its
  ticks by the width its plot actually has: a narrow chart no longer ends up with a single tick,
  and labels with a time of day get the room they need.
• A low pane of a time chart labels only the value ticks that stand a label's height apart; its
  gridlines stay.
• The value label of a short negative horizontal bar no longer runs into the category labels;
  its category leaves out its value labels instead (value_labels_omitted).
• PNG output warns with glyph_missing about characters its fonts have no glyph for.
• A declared valueAxis.step must give at most 50 ticks (an exact axis at least 2), and a
  declared timeAxis.step 1 to 50; a tiny step could draw millions and hang the renderer.
  Stacked bar charts now use a declared valueAxis.step, which they ignored.
• Tooltips and the description write a value axis unit after the values.
• A plot keeps at least 40 pixels of height and reports dense_chart instead of turning upside
  down on a small chart; a calendar reports cells smaller than 4 pixels.
• The value-axis gutter of time charts grows past 72 pixels where long labels, such as a value
  with its unit, need it (up to 40 % of the chart); small multiples measure their panel gutter
  the same way, report labels that do not fit, and shorten or leave out a unit that has no room.
• Zoom windows show their own span: timeAxis.min, max and step apply to the whole axis
  only, and stepEnd only to a window that holds the last observation.
• stepEnd after trailing missing values no longer draws over the gap.
• A declared coarser timeAxis.precision no longer removes ticks within a day.
• An unnamed layer's data table column carries the value axis unit.
• The legend of range bar groups wraps instead of running off a narrow chart.
• A sparkline refuses valueAxis.unit, valueAxis.step and timeAxis.step, which need axes.
• A PNG of a chart without a mobile variant fails with missing_mobile, like the SVG.
• labels_thinned names /data for charts with data, and its message reads "one category in
  n".

chartlet 0.7.0

Wider plots for time charts and a unit at the top tick. The specification keeps
schemaVersion: 1; every specification that rendered with 0.6.0 still renders, with the
changes in output listed under Changed.

Added

• Time charts and small multiples: valueAxis.unit, the unit after the top tick label and the
  data table's column names, instead of a title above the plot.

Changed

• Every time chart makes its value-axis gutter as wide as its widest tick label needs, at most
  the former 72 pixels, so the plot is wider; time tick labels at the left edge move inward like
  those at the right edge.

chartlet 0.6.0

Small panels, continued, and semibold text in PNG output. The specification keeps
schemaVersion: 1; every specification that rendered with 0.5.0 still renders, with the
changes in output listed under Changed and Fixed.

Added

• Time charts: timeAxis.min and timeAxis.max extend the time axis to a position such as a
  round year before the first observation.
• Time charts: "stroke": "medium", a two-pixel line for small panels.

Changed

• A compact time chart (below 320 pixels) makes its value-axis gutter as wide as its widest
  tick label needs.
• A time chart with neither a drawn title, a legend nor a value axis title above its first pane
  starts its plot near the top instead of keeping the title's room free.

Fixed

• PNG output draws semibold text semibold: the bundled semibold faces join the Inter family, so
  titles, axis titles, values and emphasized notes no longer fall back to the regular weight.

chartlet 0.5.0

Small panels and their ticks. The specification keeps schemaVersion: 1; every specification
that rendered with 0.4.0 still renders, with the changes in output listed under Fixed.

Added

• Time charts: timeAxis.step, the distance between time ticks — whole years on a calendar
  axis, units on a numeric one.
• Small multiples: noteEmphasis sets a panel's note apart, in the text color and semibold.
• Charts from 160 pixels tall (mobile variants too), for small panels.
• PNG of the mobile variant: --variant mobile --format png, with the literal colors of the
  print variant.

Fixed

• A time tick label that would run into the one before it is left out; its gridline stays.

chartlet 0.4.0

Compact charts, panel notes and step ends. The specification keeps schemaVersion: 1; every
specification that rendered with 0.3.0 still renders, with the changes in output listed under
Changed.

Added

• Compact charts from 200 pixels wide (mobile variants too): below 320 pixels the value-axis
  gutter and the margin are narrower, so a panel rendered at its width keeps its text size.
• Small multiples: panes[].note, a short finding under a panel title.
• Step lines: stepEnd, where the last step ends without an observation of its own.

Changed

• Small-multiples panel titles take two lines before they are shortened.
• A declared timeAxis.precision changes how times are named, no longer the tick spacing.

chartlet 0.3.0

Fixes and additions from moving a large site to 0.2.0. The specification keeps
schemaVersion: 1; every specification that rendered with 0.2.0 still renders, with the changes
in output listed under Changed and Fixed.

Added

• Time charts: precision per data layer, and every layer writes its times as finely as its
  own observations need — yearly means beside monthly values say only the year, and on a
  numeric axis a finely spaced helper line no longer adds decimals to the other layers. A table
  row is labelled as finely as the finest layer with a value there.
• Time charts: markers: false on a line or area layer, such as a fitted line; its tooltips
  stay on invisible targets.
• A stacked pane takes up to eight area layers.

Changed

• An exact value axis puts its ticks on multiples of the step, with the zero line:
  −2.5 to 3.5 with step 1 ticks −2, −1, 0 … 3.

Fixed

• A horizontal value axis labels only the ticks whose labels fit, so the wide labels of a
  logarithmic axis no longer run into each other.
• A horizontal range bar chart measures its value labels with the fallback reserve, so the
  label at the right end is no longer cut off.

chartlet 0.2.0

Adds stacked areas, points and range groups, exact value axes and the stylesheet in parts. The
specification keeps schemaVersion: 1; every specification that rendered with 0.1.0 still
renders, with the changes in output listed under Changed and Fixed.

Added

• Time charts: "mark": "point" draws a dot per observation and no line, as in a scatter plot.
• Time charts: "stack": "normal" on a pane stacks its area layers; the crosshair of the
  interactive module places stacked values on top of the stack.
• Time charts: "tooltips": "markers" keeps tooltips on drawn markers only, so dense lines stay
  small.
• Time charts: months ("2026-03") as times, and timeAxis.precision (year, month, day,
  minute) for how tooltips, the table and the description write times.
• Range bars: group per range, drawn in a palette color with a legend entry per group.
• Value axis: step sets the tick interval and exact keeps min and max as the ends.
• The shared stylesheet in parts: stylesheet_common() and stylesheet_types(),
  stylesheet({ types: [] }) and stylesheet({ types, common: false }), chartlet stylesheet --common and --no-common. The common part comes first; a type's part styles only charts of
  that type.

Changed

• More than 16 categories on a horizontal axis whose labels do not fit: every n-th category is
  labelled, with the room of n bands, and the warning labels_thinned.
• Charts narrower than 480 pixels draw their title at 18 pixels.
• In the shared stylesheet, each type's rules now come together, type by type.

Fixed

• The markers of the first series in a time chart with several layers take its palette color.
• A horizontal range bar chart keeps room for its last tick label.

chartlet 0.1.0

The first release without the alpha tag. The specification keeps schemaVersion: 1; every
specification that rendered with 0.1.0-alpha.7 still renders, with the changes in output listed
under Changed.

Added

• Bar charts: stack: "normal" (by value, with the total beyond each stack) and stack: "percent"
  (shares of each category's total); patterns: true draws every other series as an outline;
  references draws reference lines such as an average or a target.
• Line charts take categories and series; each series has its own color and line pattern.
• Value axis: min and max, thousandsSeparator, scale: "log" and reverse.
• Time charts: timeAxis.kind: "number" for profiles and deep time, timeAxis.reverse,
  curve: "step", legend: "end" (names at the end of the lines), sparkline: true, zones with
  a single edge, and layer colors as var(--name, #hex) whose fallback the print variant draws.
• Small multiples: independentAxes gives every panel its own value axis; mobile.columns.
• Stripes: stretch: true draws a band of color that takes any box.
• Variants: --variant print (literal colors for PDF and print renderers) and --variant social
  (1200 × 630 for Open Graph images).
• PNG output behind the optional cargo feature png, with Inter bundled (OFL-1.1).
• styles: "external" with the shared stylesheet @casoon/chartlet/chartlet.css
  (chartlet stylesheet [--types …]), so a page with many charts loads their CSS once.
• alternative: true and chartlet::text_alternative: the description and the data table as data.
• allowWarnings / --allow-warning: strict mode lets reviewed warning codes through.
• hooks: true and the optional module @casoon/chartlet/interactive: crosshair with values,
  series toggles, scroll stations and playback, reading only the static output.
• The HTML figure carries data-viz="chart" and marks its data table as the text layer.
• @casoon/chartlet-mcp: tools named chartlet_*, CHARTLET_MCP_ROOT confining outputPath,
  and a view that shows the chart in the chat of hosts that support MCP Apps.

Changed

• A line, time series or range bar whose values are all zero or more gets no margin below zero.
• One tooltip rule for lines and candles: a tooltip for every observation while observations
  stand at least 4 pixels apart, on an invisible target where no marker is drawn.
• Candle colors differ in lightness as well as in hue.
• German output writes dates as 31.08.2026; a range bar chart is a „Spannweitendiagramm“, a
  realm of a knowledge landscape a „Bereich“.
• Print and social variants write font-weight: 600, which renderers outside the browser read.
• Topic maps and knowledge landscapes are marked experimental.
• The npm package renders with its bundled WebAssembly build; a CLI is used only with binary
  or CHARTLET_BIN.