# Usage

The treemap chart provides a method for displaying hierarchical data using nested rectangles.

Treemaps display hierarchical (tree-structured) data as a set of nested rectangles. Each branch of the tree is given a rectangle, which is then tiled with smaller rectangles representing sub-branches. A leaf node's rectangle has an area proportional to a specified dimension of the data.

const config = {
  type: 'treemap',
  data: {
    datasets: [
      {
        label: 'My treemap dataset',
        tree: [15, 6, 6, 5, 4, 3, 2, 2],
        borderColor: 'green',
        borderWidth: 1,
        spacing: 0,
        backgroundColor: (ctx) => colorFromRaw(ctx),
      }
    ],
  },
  options: {
    plugins: {
      title: {
        display: true,
        text: 'My treemap chart'
      },
      legend: {
        display: false
      }
    }
  }
};

# Dataset Options

Namespaces:

  • data.datasets[index] - options for this dataset only
  • options.datasets.treemap - options for all treemap datasets
  • options.elements.treemap - options for all treemap elements
  • options - options for the whole chart

The treemap chart allows a number of properties to be specified for each dataset. These are used to set display properties for a specific dataset.

Name Type Scriptable (opens new window) Default
backgroundColor Color (opens new window) Yes undefined
borderColor Color (opens new window) Yes undefined
borderRadius number | object Yes 0
borderWidth number|object - 0
captions object -
dividers object -
groups string[] - undefined
hoverBackgroundColor Color (opens new window) Yes undefined
hoverBorderColor Color (opens new window) Yes undefined
hoverBorderWidth number Yes undefined
key string - undefined
label string - undefined
labels object -
rtl boolean - false
spacing number - 0.5
sumKeys string[] - undefined
tree number[] | object[] | object - required
treeLeafKey string - _leaf

All these values, if undefined, fallback to the scopes described in option resolution (opens new window).

# General

Name Description
groups Define how to display multiple levels of hierarchy. Data is summarized to groups internally.
key Define the key name in data objects to use for value.
label The label for the dataset which appears in the legend and tooltips.
rtl If true, the treemap elements are rendering from right to left.
sumKeys Define multiple keys to add additional sums, on top of the key one, for scriptable options use.
tree Tree data should be provided in tree property of dataset. data is then automatically build.
treeLeafKey The name of the key where the object key of leaf node of tree object is stored. Used only when tree is an object, as hierarchical data.

Only the tree, treeLeafKey, key, sumKeys and groups options need to be specified in the dataset namespace.

function colorFromRaw(ctx) {
  if (ctx.type !== 'data') {
    return 'transparent';
  }
  const value = ctx.raw.v;
  let alpha = (1 + Math.log(value)) / 5;
  const color = 'green';
  return helpers.color(color)
    .alpha(alpha)
    .rgbString();
}
const data = [
  {category: 'main', value: 1},
  {category: 'main', value: 2},
  {category: 'main', value: 3},
  {category: 'other', value: 4},
  {category: 'other', value: 5},
];
const config = {
  type: 'treemap',
  data: {
    datasets: [{
      tree: data,
      key: 'value',
      groups: ['category'],
      backgroundColor: (ctx) => colorFromRaw(ctx),
    }]
  },
};

# Styling

The style of the treemap element can be controlled with the following properties:

Name Description
backgroundColor The treemap element background color.
borderColor The treemap element border color.
borderRadius Radius of the rectangle of treemap element (in pixels).
borderWidth The treemap element border width (in pixels).
spacing Fixed distance (in pixels) between all treemap elements.

If the value is undefined, fallbacks to the associated elements.treemap.* options.

# borderRadius

If this value is a number, it is applied to all corners of the rectangle (topLeft, topRight, bottomLeft, bottomRight). If this value is an object, the topLeft property defines the top-left corners border radius. Similarly, the topRight, bottomLeft, and bottomRight properties can also be specified. Omitted corners have radius of 0.

# Interactions

The interaction with each element can be controlled with the following properties:

Name Description
hoverBackgroundColor The treemap element background color when hovered.
hoverBorderColor The treemap element border color when hovered.
hoverBorderWidth The treemap element border width (in pixels) when hovered.

If the value is undefined, fallbacks to the associated elements.treemap.* options.

# Labels

Namespaces:

  • data.datasets[index].labels - options for this dataset only
  • options.datasets.treemap.labels - options for all treemap datasets
  • options.elements.treemap.labels - options for all treemap elements
  • options - options for the whole chart

The labels options can control if and how a label, to represent the data, can be shown in the rectangle, with the following properties:

Name Type Scriptable (opens new window) Default
align string Yes center
color Color | Color[] Yes 'black'
display boolean - false
formatter function Yes
font Font | Font[] Yes {}
hoverColor Color | Color[] Yes undefined
hoverFont Font | Font[] Yes {}
overflow string Yes cut
padding number - 3
position string Yes middle

All these values, if undefined, fallback to the scopes described in option resolution (opens new window).

WARNING

Labels only apply if display is true.

# Align

The align property specifies the text horizontal alignment used when drawing the label. The possible values are:

  • center: the text is centered. It is the default.
  • left: the text is left-aligned.
  • right: the text is right-aligned.

# Overflow

The overflow property controls what happens to a label that is too big to fit into a rectangle. The possible values are:

  • cut: if the label is too big, it will be cut to stay inside the rectangle. It is the default.
  • hidden: the label is removed altogether if the rectangle is too small for it.
  • fit: the label will be automatically fit inside the rectangle if its dimension is bigger than the rectangle size.

# Position

The position property specifies the text vertical alignment used when drawing the label. The possible values are:

  • middle: the text is in the middle of the rectangle. It is the default.
  • top: the text is in the top of the rectangle.
  • bottom: the text is in the bottom of the rectangle.

# Formatter

Data values are converted to string. If values are grouped, the value of the group and the value (as string) are shown.

This default behavior can be overridden by the formatter which is a scriptable (opens new window) option.

A formatter can return a string (for a single line) or an array of strings (for multiple lines, where each item represents a new line).

In the following example, every label of the treemap would be displayed with the unit.

const config = {
  type: 'treemap',
  data: {
    datasets: [{
      tree: [15, 6, 6, 5, 4, 3, 2, 2],
      labels: {
        display: false,
        formatter: (ctx) => 'Kmq ' + ctx.raw.v
      }
    }]
  },
};

# Fonts and colors

When the label to draw has multiple lines, you can use different font and color for each row of the label. This is enabled configuring an array of fonts or colors for those options. When the lines are more than the configured fonts of colors, the last configuration of those options is used for all remaining lines.

See on Chart.js documentation more details about font (opens new window) and color (opens new window) options.

# Captions

Namespaces:

  • data.datasets[index].captions - options for this dataset only
  • options.datasets.treemap.captions - options for all treemap datasets
  • options.elements.treemap.captions - options for all treemap elements
  • options - options for the whole chart

The captions options can control if and how a captions, to represent the group of the chart, can be shown in the rectangle, with the following properties:

Name Type Scriptable (opens new window) Default
align string Yes undefined but left is used because default rtl option is false.
color Color (opens new window) Yes 'black'
display boolean - true
font (opens new window) Font Yes {}
formatter function Yes
hoverColor Color (opens new window) Yes undefined
hoverFont (opens new window) Font Yes {}
padding number - 3

All these values, if undefined, fallback to the scopes described in option resolution (opens new window).

# Caption Align

The align property specifies the text horizontal alignment used when drawing the caption. The possible values are:

  • left: the text is left-aligned.
  • center: the text is centered.
  • right: the text is right-aligned.

If undefined, right is used if rtl option is set to true, otherwise left.

# Caption Formatter

If values are grouped, the value of the group is shown in the chart as caption for all elements belonging to the group.

This default behavior can be overridden by the formatter which is a scriptable (opens new window) option.

A formatter can return a string.

In the following example, every caption of the treemap would be displayed with an additional label.

const data = [
  {category: 'main', subcategory: 'one', value: 1},
  {category: 'main', subcategory: 'one', value: 5},
  {category: 'main', subcategory: 'one', value: 3},
  {category: 'main', subcategory: 'two', value: 2},
  {category: 'main', subcategory: 'two', value: 1},
  {category: 'main', subcategory: 'two', value: 8},
  {category: 'other', subcategory: 'one', value: 4},
  {category: 'other', subcategory: 'one', value: 5},
  {category: 'other', subcategory: 'two', value: 4},
  {category: 'other', subcategory: 'two', value: 1},
];
const config = {
  type: 'treemap',
  data: {
    datasets: [{
      tree: data,
      key: 'value',
      groups: ['category', 'subcategory', 'value'],
      captions: {
        display: true,
        formatter(ctx) {
          return ctx.type === 'data' ? 'G: ' + ctx.raw.g : '';
        }
      },
    }]
  },
};

# Dividers

Namespaces:

  • data.datasets[index].dividers - options for this dataset only
  • options.datasets.treemap.dividers - options for all treemap datasets
  • options.elements.treemap.dividers - options for all treemap elements
  • options - options for the whole chart

The divider is a line which splits a treemap elements in grouped elements and can be controlled with the following properties:

Name Type Scriptable (opens new window) Default
display boolean - false
lineCapStyle string - 'butt'
lineColor Color (opens new window) - 'black'
lineDash number[] - []
lineDashOffset number - 0
lineWidth number - 1

All these values, if undefined, fallback to the scopes described in option resolution (opens new window).

# Line Styling

The style of the divider line can be controlled with the following properties:

Name Description
display If true, the dividers will be applied to the grouped treemap elements, only if grouping.
lineCapStyle Cap style of the divider line. See MDN (opens new window).
lineColor Color of the divider line.
lineDash Length and spacing of divider dashes. See MDN (opens new window).
lineDashOffset Offset for divider line dashes. See MDN (opens new window).
lineWidth Divider line width (in pixels).

If the value is undefined, fallbacks to the associated elements.treemap.dividers.* options.

Last Updated: 10/17/2023, 4:20:12 AM