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D3plus

Pyramid

Creates a population pyramid: horizontal bars for two groups (the first groupBy level, e.g. Male / Female) extending in opposite directions from a shared center line, one row per y category (e.g. age band). Values stay positive — the left side is mirrored internally and the value axis reads magnitudes on both halves. The category labels run down a gutter between the halves (or beside the chart, with categoryPosition). Deeper groupBy levels stack within each side.

Basic example

Section titled “Basic example”

Pass positive values: the first groupBy level splits the rows into two sides, the first side (here Male) is mirrored to the left, and the value axis reads magnitudes outward from zero on both halves. The y categories (age bands) run down a gutter between the halves, bottom to top in data order, and each side is named above its half.

categoryPosition

Where the category labels (e.g. age bands) are drawn: "center" (default) down a gutter between the two halves, as wide as the widest label, with each half reading outward from zero at its edge; or "left", on a regular category axis beside the chart.

Draws the name of each side centered above its half of the chart.

Centers the value axis on zero so both halves share one scale, sized to the largest single side. Set to false to fit the data instead. Ignored when xDomain or xConfig.domain is set.

Left labels

Section titled “Left labels”

categoryPosition("left") moves the categories onto a regular axis beside the chart, so the two halves meet on a single zero line.

categoryPosition

Where the category labels (e.g. age bands) are drawn: "center" (default) down a gutter between the two halves, as wide as the widest label, with each half reading outward from zero at its edge; or "left", on a regular category axis beside the chart.

Stacked sides

Section titled “Stacked sides”

Deeper groupBy levels stack within each side. A sub-group keeps one color and one legend entry on both sides, and is stacked at the same distance from the center line on each, largest nearest the center.

groupBy

Defines the mapping between data and shape. The value can be a String matching a key in each data point (default is "id"), or an accessor Function that returns a unique value for each data point. Additionally, an Array of these values may be provided if the visualization supports nested hierarchies.

["Sex", "Area"]

Percent and comparison

Section titled “Percent and comparison”

percent(true) draws every bar as a share of the whole population, so pyramids of different sizes compare by shape. comparison traces a second value for each row as an outline around each side — here the same population in 2000, scaled to its own total.

Draws each value as a fraction of the current frame's total (both sides together), with the value axis and tooltip reading percentages.

An optional comparison value for each row, drawn as an outline around each side's bars (e.g. the same population a decade earlier). Accepts a data key or an accessor function. Included in the symmetric domain, the tooltip, and, in percent mode, scaled to its own total.

Timeline

Section titled “Timeline”

With time, the timeline steps (or plays) through the years. axisPersist(true) keeps one symmetric axis sized to every year, so the pyramid’s shape change reads directly.

Accessor function or string key for the time dimension of each data point.

Determines whether the x and y axes should have their scales persist while users filter the data, the timeline being the prime example (set this to true to make the axes stay consistent when the timeline changes).

Configuration

import {Pyramid} from "@d3plus/core";

Extends BarChart → Plot → Viz.

activefalse | function

The active callback function for highlighting shapes.

annotationsunknownDefault unknown

Allows drawing custom shapes to be used as annotations in the provided x/y plot. This method accepts custom config objects for the Shape class, either a single config object or an array of config objects. Each config object requires an additional parameter, the "shape", which denotes which Shape sub-class to use (Rect, Line, etc).

Additionally, each config object can also contain an optional "layer" key, which defines whether the annotations will be displayed in "front" or in "back" of the primary visualization shapes. This value defaults to "back" if not present ("front" for callouts).

Three more kinds draw chart notes: "Callout" anchors wrapped text in a box at each data row's x/y (in data units, or plot-area fractions with xRef/yRef: "plot"), offset by dx/dy pixels and joined to its anchor by a connector ending in an arrowhead or dot (see CalloutAnnotation); "ReferenceLine" and "ReferenceBand" draw what referenceLines and referenceBands entries expand into. All annotations follow zoom and never respond to the pointer or keyboard.

axisPersistbooleanDefault unknown

Determines whether the x and y axes should have their scales persist while users filter the data, the timeline being the prime example (set this to true to make the axes stay consistent when the timeline changes).

backgroundConfigrecordDefault {duration: 0, fill: transparent}

A d3plus-shape configuration Object used for styling the background rectangle of the inner x/y plot (behind all of the shapes and gridlines).

barWidthstring | false | function

Makes each bar as wide as its own measure (a data key or accessor), read off the merge of the bar's rows, so stacked segments add up unless aggs says otherwise. The bars sit end to end along a continuous discrete axis of cumulative width, labeled at their centers. Off (undefined) by default.

barWidthShareboolean | "opposite"Default false

With barWidth, adds each bar's share of the total width to its category's axis label: on a second line beneath the name along a horizontal axis, in parentheses after it along a vertical one. Along a horizontal axis, a name wraps to fit a narrow bar, widening into room its neighbors leave; a label that still can't fit is left out, and the labels rotate, showing the name alone, only when half or more can't fit. "opposite" puts the shares on the axis across the bars from the names instead: above them along a horizontal axis (x2Config), right of them along a vertical one (y2Config). In small multiples, each panel's shares are of that panel's own total width. Off (false) by default.

barWidthShareFormatfunction

With barWidthShare, returns each bar's width-share label in place of its percentage. Called with the merge of the bar's rows' data and {share, size, total, text}: the bar's share of the total width (0–1), its width measure, every bar's combined width, and the default label (such as "23%"). Unset by default.

baselinenumberDefault 0

Starts the value axis (the x axis for horizontal charts) at a value: baseline(n) renders exactly like yDomain([n]) (or xDomain([n])). Bars, areas, and stems still grow from the chart's own 0 in the Plots that draw from one (such as BarChart, AreaPlot, Histogram, and Lollipop), so with baselineBreak on (their default) the axis breaks back to a 0 tick and bars run through the break, with its gap cut across them, and with it off the axis stretches down to 0. As with yDomain([n]), only n is pinned: the far end comes from the data and is rounded where the axis would round it with no domain set (left at the data when the axis config's rounding is "none"), and marks for values past n stop at the axis's edge. When every value sits at or below n, it ends the axis instead, like yDomain([undefined, n]). A bound given in yDomain/xDomain wins. Returns the chart's own baseline when none is set.

baselineBreakbooleanDefault false

When the domain of a linear value axis stops short of the baseline (e.g. [1100, 2100] with a baseline of 0), keeps the baseline as the axis's end tick and breaks the axis between it and the domain: a short stretch of axis holds the baseline tick and two tilted marks with a gap in the axis line, then the domain spans the rest. Style it with the axis's baselineBreakConfig. In a Plot it applies to a user-supplied value domain (yDomain/yConfig.domain, or the x versions for horizontal charts), and bars and areas start at the baseline tick, with the break's gap cut across them (baselineBreakConfig's mask); turned off, a yDomain stretches to reach the baseline while a yConfig.domain is kept and cuts its bars off at the axis. Defaults to true for the Plots whose marks grow from 0, such as BarChart, AreaPlot, Histogram, and Lollipop (each chart lists its own default), and false for other Plots and a standalone Axis.

Both halves meet at the center line, so the value axis never breaks away from zero.

bufferboolean | recordDefault assign({}, defaultBuffers, {Bar: false, Line: false})

Determines whether or not to add additional padding at the ends of x or y scales. The most commone use for this is in Scatter Plots, so that the shapes do not appear directly on the axis itself. The value provided can either be true or false to toggle the behavior for all shape types, or a keyed Object for each shape type (ie. {Bar: false, Circle: true, Line: false}).

categoryPosition"center" | "left"Default "center"

Where the category labels (e.g. age bands) are drawn: "center" (default) down a gutter between the two halves, as wide as the widest label, with each half reading outward from zero at its edge; or "left", on a regular category axis beside the chart.

classNamestring | array.<string> | undefined

CSS classes added to the outermost element this chart or component draws into, next to its fixed d3plus classes, so page CSS can target it: a chart's root <svg class="d3plus-viz"> (its <canvas> with the Canvas renderer) and a standalone component's <svg>. Takes a space-separated string or an array. A new value replaces the classes the previous one added; unset adds none. Tooltips take their own tooltipConfig.className.

colorDefaultscolordefaultsconfig

Overrides the default colors used when assigning fills from data and choosing legible text colors: dark and light (the text colors picked for contrast against a background), missing (null/undefined values), on/off (true/false values), sequential (the anchor hue for magnitude ramps), and scale (the categorical palette, given as a d3 ordinal scale or an array of colors). Keys are merged into the current defaults, and a Viz passes its overrides down to the shapes and components it draws.

comparisonstring | false | function

An optional comparison value for each row, drawn as an outline around each side's bars (e.g. the same population a decade earlier). Accepts a data key or an accessor function. Included in the symmetric domain, the tooltip, and, in percent mode, scaled to its own total.

comparisonConfigrecordDefault {stroke: () => backgroundInk(viz), strokeDasharray: "4 3", strokeOpacity: 1, strokeWidth: 1.5}

Line styles for the comparison outline: stroke, strokeWidth, strokeOpacity, and strokeDasharray. Each may be a function of the side value and its index (0 = left).

confidenceunknown

The confidence interval as an array of [lower, upper] bounds. Lines draw it as a shaded band; bars draw an error bar per bar, from the lower to the upper bound with a cap at each end (a stacked bar's bounds keep their distance from its value, measured from the bar's stacked end). Either bound may be false for a one-sided interval, and a row without a bound pinches the band onto its line. The value axis widens to fit the bounds, and tooltips list them (see confidenceConfig.tooltip). Pass false to turn the interval off.

Pass an array of bands, outermost first, to draw nested bands around each line (a fan): each band is a [lower, upper] pair or [lower, upper, label], or a {lower, upper, label} object, and confidenceConfig.bandOpacity shades them from the widest (lightest) to the narrowest (darkest). Tooltips list each band's range under its label ("Band 1", "Band 2", … when unlabeled), and bars draw the first band's error bar.

confidenceConfigrecordDefault
function
{fill: (d, i) => {
  const { Line, stroke } = this.schema.shapeConfig;
  const s = Line && Line.stroke !== undefined ? Line.stroke : stroke;
  return typeof s === "function" ? s(d, i) : s;
}, fillOpacity: 0.5}

Configuration object for shapes rendered as confidence intervals. A line's band is an Area, filled with the line's color at half opacity. A bar's error bar is a Path styled by stroke (default a shade darker than the bar), strokeWidth (default 2), strokeDasharray, strokeOpacity, and capWidth: the length of each end cap, in pixels or as a percentage string of the bar's thickness (default "50%"). Keys nested under Area or Bar apply only to that shape's interval. With several bands, bandOpacity sets how each band looks where it is the innermost band drawn: an array ramps from the outermost band to the innermost (default [0.15, 0.6]), a number gives every band that opacity, and either replaces fillOpacity. tooltip (default true) lists the bounds in tooltips: a "Lower Bound" and "Upper Bound" row for a single mark, and a range after each series' value in a shared tooltip; set it to false to leave them out. Accepted keys: any key the Area or Path shape takes at the top level, plus bandOpacity, capWidth, tooltip, Area (Area keys), and Bar (Path keys and capWidth); any other key logs a warning.

configd3plusconfig

Methods that correspond to the key/value pairs and returns this class.

crosshairConfigrecordDefault
function
{stroke: () => themed(this._theme, (t) => t.textMuted, colorGray.500), strokeDasharray: 4 3, strokeWidth: 1}

Paint for the shared tooltip's crosshair guide line (stroke, strokeWidth, strokeDasharray, strokeOpacity, …). Merged into the current config.

datastring | array.&lt;datapoint&gt; | object

The primary data array used to draw the visualization. The value passed should be an Array of objects or a String representing a filepath or URL to be loaded. The following filetypes are supported: csv, tsv, txt, and json.

If your data URL needs specific headers to be set, an Object with a "url" and "headers" (or any other fetch request option) may also be passed. An Object with any other key is a data row, not a request.

Additionally, a custom formatting function can be passed as a second argument to this method. This custom function will be passed the data that has been loaded, as long as there are no errors. This function should return the final array of obejcts to be used as the primary data array. For example, some JSON APIs return the headers split from the data values to save bandwidth. These would need be joined using a custom formatter.

If you would like to specify certain configuration options based on the yet-to-be-loaded data, you can also return a full config object from the data formatter (including the new data array as a key in the object).

To re-fetch a URL on an interval and redraw when its data changes, set dataPollingInterval; each poll runs the same formatter.

Defaults to an empty array ([]).

discreteCutoffnumberDefault unknown

When the width or height of the chart is less than or equal to this pixel value, the discrete axis will not be shown. This helps produce slick sparklines. Set this value to 0 to disable the behavior entirely.

facetstring | false | function

Splits the chart into small multiples: a grid of equally sized panels, one per distinct value of this data key or accessor, each drawing the chart for that value's rows. The panels share one legend, color scale, title, and timeline, color each series the same way, and hover, tooltips, and legend clicks apply across all of them. Pass false to draw a single chart. See facetConfig for the grid's layout and shared scales.

facetConfigfacetconfig

Configuration for small multiples (see facet), merged into the current config: - columns / rows: the grid's shape. Chosen by default to make the panels as large as the chart's shape allows. - padding: the space between panels, in pixels (default 20). - sort: panel order — "ascending" (default), "descending", "data" (first appearance), a comparator over facet values, or an Array of values. - scales: "shared" (default) gives every panel of a chart with axes the same x/y domains; "independent" fits each panel to its own rows. Funnel defaults to "independent" (each panel sized to its own widest stage); "shared" sizes every panel against the widest stage across all panels. PolarArea and RadialBar default to "independent" (each panel's rings and ticks fit its own values); "shared" gives every panel the same value domain. - axes: with shared scales, "outer" (default) labels the axes only along the grid's left and bottom edges; "all" labels every panel. An object sets each axis on its own, as in {x: "all", y: "outer"}: every panel labels its x axis, only the left column labels its y axis, and the panels' plot areas line up. BumpChart defaults to "all", and Marimekko labels its categories on every panel and its 0–100% share axis only along the outer edge, even with independent scales. - title: a (value, data) => string function for each panel's title, or false to hide panel titles. - titleConfig: TextBox config for the panel titles (fontSize, fontWeight, fontColor, textAnchor, padding, …).

fontFamilystring | array.&lt;string&gt;

The font family used throughout the visualization.

groupBystring | function | array.&lt;string | function&gt;

Defines the mapping between data and shape. The value can be a String matching a key in each data point (default is "id"), or an accessor Function that returns a unique value for each data point. Additionally, an Array of these values may be provided if the visualization supports nested hierarchies.

groupPaddingnumberDefault unknown

The pixel space between groups of bars.

highlightfalse | function

Persistently emphasizes the data points matching the given predicate: the matching marks keep their color while every other mark is de-emphasized to a neutral gray (the "emphasis" form — highlight one series, gray the rest). Unlike hover/active (transient, opacity-based), highlight is a standing state that survives pointer movement. Pass false to clear it.

hoverfalse | function

The hover callback function for highlighting shapes on mouseover.

labelConnectorConfigrecordDefault {strokeDasharray: 1 1}

The d3plus-shape config used on the Line shapes created to connect lineLabels to the end of their associated Line path.

legendboolean | functionDefault function

Whether to display the legend. By default, the legend shows when it has more than one entry and each entry stands for a single group (or two groups at most), or when the entries are colored by a category that isn't a groupBy level (see color), in which case each entry is labelled by its category. Pass false to hide it, true to always show it, or a (config, data) => boolean function to decide.

lineMarkerConfigrecordDefault
function
{fill: (d, i) => colorAssign(this._id(d, i), linkedColorDefaults(this)), r: 3}

Shape config for the Circle shapes drawn by the lineMarkers method.

lineMarkersbooleanDefault unknown

Draws circle markers on each vertex of a Line.

localestring | object

The locale used for all text and number formatting. Supports the locales defined in d3plus-format. The locale can be a complex Object, a locale code (like "en-US"), or a 2-digit language code (like "en"). If a 2-digit code is provided, the "findLocale" function is used to identify the most approximate locale.

onstring

Event listener for the specified event typenames. Mirrors the core d3-selection behavior.

parentunknown

Parent config used by the wrapper.

percentbooleanDefault false

Draws each value as a fraction of the current frame's total (both sides together), with the value axis and tooltip reading percentages.

renderfunction

Draws the visualization given the specified configuration.

rendererboolean | "svg" | "canvas"

Selects which @d3plus/render backend paints the visible output. "svg" = SvgRenderer (default), "canvas" = CanvasRenderer. Boolean arguments both normalize to "svg".

selectstring | htmlelement

The SVG container element as a d3 selector or DOM element. Defaults to undefined.

shapeConfigd3plusconfig

Configuration object with key/value pairs applied as method calls on each shape.

sideTitleConfigtextboxconfigDefault {fontColor: () => backgroundInk(viz), fontSize: 14, fontWeight: 600, padding: 2, textAnchor: "middle", verticalAlign: "middle"}

TextBox styles for the side titles.

sideTitlesbooleanDefault true

Draws the name of each side centered above its half of the chart.

sidesarray.&lt;unknown&gt;

The side values (from the first groupBy level) as [left, right]. Unlisted values are drawn on the right. Defaults to the order sides first appear in the data.

sizefalse | plotaccessorarg

Sets the size of bubbles to the given Number, data key, or function.

stackOffsetstring | stackoffsetfnDefault stackOffsetDiverging

Sets the vertical offset applied to stacked series. Accepts a named offset — "diverging" (default), "none", "expand", "silhouette", or "wiggle" — or a custom offset function. Unknown names warn and fall back to "diverging". If value is not specified, returns the current stack offset function.

stackOrderstackorderinputDefault stackOrderTotalDescending

Sets the order of stacked series, from the bottom of the stack upward. Accepts: - a named order: "descending" (default) / "ascending" by summed value, "key" / "keyReverse" alphabetically by series key, "none" / "data" for input order, or d3's "insideOut", "appearance", "reverse"; - an Array of series keys for an explicit order; - a value accessor, or a {value, order} config, to rank series by an aggregate of any data field.

Unknown named strings warn and fall back to "descending". If value is not specified, returns the current stack order.

symmetricbooleanDefault true

Centers the value axis on zero so both halves share one scale, sized to the largest single side. Set to false to fit the data instead. Ignored when xDomain or xConfig.domain is set.

thresholdnumber | function

The threshold value for bucketing small data points together, as a share of the total. On a stacked Plot, the series whose summed value across every position is under that share of the whole chart's total merge into one series, stacked on top. A bucket needs at least two items, and its tooltips list them. Off (0) by default on Plot charts.

thresholdKeystring | function

Accessor for the value used in the threshold algorithm. A stacked Plot defaults to its stacked value.

timestring | false | function

Accessor function or string key for the time dimension of each data point.

timelineDefaultstring | date | array.&lt;string | date&gt;

The starting time or range for the timeline. Can be a single Date/String, or an Array of 2 values representing the min and max.

tooltipConfigtooltipconfigDefault {tbody: (d: DataPoint, i: number) => tooltipRows(viz, d, i)}

Configuration for the tooltip component.

totalstring | boolean | function

Accessor function or string key for the total value displayed in the visualization.

translatefunction

Defines how informational text strings should be displayed. By default, this function will try to find the string in question (which is the first argument provided to this function) inside of an internally managed translation Object. If you'd like to override to use custom text, simply pass this method your own custom formatting function.

trendLinetrendlinetype

Draws an automatic trend line fit to the plotted data: true (or "linear") for a least-squares line, or one of "exponential", "logarithmic", "power", or "polynomial". By default each series gets its own line in its color; see trendLineConfig for grouping, a confidence band, and styling. On a chart with a discrete axis, the line runs along that axis, fitting categories by their order. Set to false (the default) to remove.

trendLineConfigrecord

Options for the trend lines drawn by trendLine, merged into the current config: - group: "series" (default) fits one line per series, colored to match it; "all" fits a single line to every point. - order: the polynomial degree when trendLine is "polynomial" (default 2). - confidence: draws a confidence band around a linear fit (default false). - confidenceLevel: the band's confidence level (default 0.95). - confidenceConfig: Area shape config for the band (default {fillOpacity: 0.15}; fill defaults to the line color). - projection: extends each line past the end of its data, by a number of steps at the data's own spacing (e.g. 5 more years), or to an end value with {to: 2030} (default 0, off). The axis widens to fit, and a linear fit's band becomes a prediction interval that fans out over the projection. Hovering a projected step lists each series' projected value. Ignored on a category axis. - projectionConfig: Line shape config for the projected stretch, over the line's own styles (default {strokeDasharray: "2 4"}). - tooltip: shows the fitted equation and R² when hovering a line (default true). - Any other key (stroke, strokeWidth, strokeDasharray, …) styles the Line shape.

Stacked charts always fit one line to the stack totals.

xplotaccessorargDefault
function
d => d["x"]

Accessor function or string key for the x-axis value of each data point.

x2plotaccessorargDefault
function
d => d["x2"]

Accessor function or string key for the secondary x-axis value of each data point.

x2ConfigrecordDefault {}

A pass-through to the underlying Axis config used for the secondary x-axis. Includes additional functionality where passing "auto" as the value for the scale method will determine if the scale should be "linear" or "log" based on the provided data.

xConfigrecordDefault
function
{gridConfig: {stroke: (d) => {
  if (this.schema.discrete?.charAt(0) === "x" || this._swarm?.cross === "x") return "transparent";
  const range = this._xAxis.range();
  const position = this._xAxis._getPosition.bind(this._xAxis)(d.id);
  if (range[0] === position) return "transparent";
  return chartGridline(this);
}}}

A pass-through to the underlying Axis config used for the x-axis. Includes additional functionality where passing "auto" as the value for the scale method will determine if the scale should be "linear" or "log" based on the provided data.

yplotaccessorargDefault
function
d => d["y"]

Accessor function or string key for the y-axis value of each data point.

y2plotaccessorargDefault
function
d => d["y2"]

Accessor function or string key for the secondary y-axis value of each data point.

y2ConfigrecordDefault {}

A pass-through to the underlying Axis config used for the secondary y-axis. Includes additional functionality where passing "auto" as the value for the scale method will determine if the scale should be "linear" or "log" based on the provided data.

yConfigrecordDefault
function
{gridConfig: {stroke: (d) => {
  if (this.schema.discrete?.charAt(0) === "y" || this._swarm?.cross === "y") return "transparent";
  const range = this._yAxis.range();
  const position = this._yAxis._getPosition.bind(this._yAxis)(d.id);
  if (range[range.length - 1] === position) return "transparent";
  return chartGridline(this);
}}}

A pass-through to the underlying Axis config used for the y-axis. Includes additional functionality where passing "auto" as the value for the scale method will determine if the scale should be "linear" or "log" based on the provided data.

Note: If a "domain" array is passed to the y-axis config, it will be reversed.