JavaScript/jQuery TreeMap Options

In hierarchical data sources, objects normally have at least one nested array of objects. To specify the field providing this array, assign its name to the childrenField option. Such hierarchical objects will be visualized by groups of tiles.

See Also

• dataSource - specifies the origin of data for the widget.
• valueField - specifies the data source field that provides values for tiles.
• labelField - specifies the data source field that provides texts for tile and group labels.

There are several approaches to colorizing tiles.

• Colorizing each tile uniquely into the color specified directly in the data object.
• Colorizing tiles using the colorizer.
• Specifying a single color for all tiles using the tile.color option.

You can use the first approach only if objects of your data source contain a field providing colors. If so, assign the name of this field to the colorField option. The colors must have one of the following formats:

• Hexadecimal colors
• RGB colors
• RGBA colors
• Predefined/cross-browser color names
• Predefined SVG colors

This approach has the highest priority among the others. To get familiar with the other two approaches, see the colorizer and tile.color option descriptions.

There are several approaches to colorizing tiles.

• Colorizing each tile uniquely into the color specified directly in the data object.
• Colorizing tiles using the colorizer.
• Specifying a single color for all tiles using the tile.color option.

If for some reason you cannot use the first approach, colorize tiles using the colorizer object. It offers three colorization algorithms: "discrete", "gradient" and "range". For more information on how to use each algorithm, refer to the type option description.

To find out how else you can colorize tiles, see the colorField and tile.color option descriptions.

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This option accepts one of the following.

• Array of objects
  A simple JavaScript array containing a collection of plain objects.

• URL
  A URL to JSON data or to a service returning data in JSON format.

• DataSource or its configuration object
  A DataSource is an object that provides a handy API for data processing. A DataSource is a stateful object, which means that it saves data processing settings and applies them each time data is loaded. All underlying data access logic of a DataSource is isolated in a Store. A Store provides an API for reading and modifying data. Unlike the DataSource, a Store is a stateless object.

Basically, all data providers contain data objects. Objects that have a plain structure are visualized by tiles. For example, the following data source produces four individual tiles.

var treeMapOptions = {
    // ...
    dataSource: [
        { name: 'Apples', value: 10 },
        { name: 'Oranges', value: 13 },
        { name: 'Cucumbers', value: 4 },
        { name: 'Tomatoes', value: 8 }
    ]    
};

Hierarchically-structured objects are visualized by groups of tiles. For example, the following data source arranges the tiles from the previous code snippet in two groups: "Fruits" and "Vegetables".

var treeMapOptions = {
    // ...
    dataSource: [{
        name: 'Fruits',
        items: [
            { name: 'Apples', value: 10 },
            { name: 'Oranges', value: 13 }
        ]
    }, {
        name: 'Vegetables',
        items: [
            { name: 'Cucumbers', value: 4 },
            { name: 'Tomatoes', value: 8 }
        ]
    }] 
};

After providing data, bind it to the widget using the valueField, labelField and childrenField options.

In certain cases, you may have a plain data source that implies a hierarchical structure. For example, the following code declares such a data source. Nevertheless, it will be visualized in the same manner as the data source from the code snippet above.

var treeMapOptions = {
    // ...
    dataSource: [
        { id: 1, name: 'Fruits'},
        { parent: 1, name: 'Apples', value: 10 },
        { parent: 1, name: 'Oranges', value: 13 },

        { id: 2, name: 'Vegetables' },
        { parent: 2, name: 'Cucumbers', value: 4 },
        { parent: 2, name: 'Tomatoes', value: 8 }
    ],
    idField: 'id',
    parentField: 'parent'
};

Note that in this data source, objects that have children have the "id" field whose value is unique. Their children have the "parent" field pointing at the parent's ID. The "id" and "parent" fields can have other names, but in any case, they must be assigned to the idField and parentField options. Otherwise, you will get four individual tiles (as in the first code snippet) instead of two groups by two tiles. To specify the fields that provide values and labels, use the valueField and labelField options as well.

The examples above show how to provide data using an array of objects. If you are looking for a more powerful and versatile data solution, consider using the DataSource object. To learn how to implement a DataSource that serves your needs best, refer to the Data Source Examples article.

View hierarchical Data Structure Demo View Flat Data Structure Demo

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See Also

• getDataSource()
• Data Layer - Overview
• Data Layer - Data Source Examples

You can configure this option in an ASP.NET MVC Control as follows:

@(Html.DevExtreme().WidgetName()
    .ElementAttr("class", "class-name")
    // ===== or =====
    .ElementAttr(new {
        @id = "elementId",
        @class = "class-name"
    })
    // ===== or =====
    .ElementAttr(new Dictionary<string, object>() {
        { "id", "elementId" },
        { "class", "class-name" }
    })

)

@(Html.DevExtreme().WidgetName() _
    .ElementAttr("class", "class-name")
    ' ===== or =====
    .ElementAttr(New With {
        .id = "elementId",
        .class = "class-name"
    })
    ' ===== or =====
    .ElementAttr(New Dictionary(Of String, Object) From {
        { "id", "elementId" },
        { "class", "class-name" }
    })
)

These features allow a user to export your widget into a document or print it. When exporting is enabled, the "Exporting/Printing" button appears in the widget. A click on it invokes a drop-down menu that lists exporting and printing commands. The following formats are supported for exporting into: PNG, PDF, JPEG, SVG and GIF.

See Also

• exportTo(fileName, format)
• print()
• DevExpress.viz.exportFromMarkup(markup, options)

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A group is an element that collects several tiles in it. In terms of data, it is a node that has children in the current context. Groups appear only if the data source implies a hierarchical structure.

The following list provides an overview of group features that you can configure using the group object.

• Labels
  Each group is identified by a label. Its appearance can be changed using the fields of the label object. If the group's width is too small, the label will be hidden.
• Headers' Height
  Group headers contain labels. To specify the height of the group headers, use the headerHeight option.
• Color
  There are several approaches to colorizing the group headers. Refer to the color option description to find information about all of them.
• Hover and Selection Styles
  A group can be in the hover or selected state. In these states, its style changes to the one specified by the hoverStyle or selectionStyle object respectively. A group can also enter the hover or selected state when a nested tile enters it. To enable this feature, assign true to the interactWithGroup option of the root configuration object.
• Border's Appearance
  Specify the fields of the border object to configure group borders.

An object assigned to the group field configures all groups in the widget. To customize a specific group, pass a similar object to the customize(options) method of the node represented by the group.

See Also

• group.hoverStyle
• tile.hoverStyle
• group.hoverEnabled
• onHoverChanged

In certain cases, you may have a plain data source that implies a hierarchical structure. For example, the following code declares a data source that, despite being plain, can be rearranged into a hierarchy of two groups with two items in each.

var treeMapOptions = {
    // ...
    dataSource: [
        // Group 1
        { id: 1, name: 'Fruits'},
        { parent: 1, name: 'Apples', value: 10 },
        { parent: 1, name: 'Oranges', value: 13 },

        // Group 2
        { id: 2, name: 'Vegetables' },
        { parent: 2, name: 'Cucumbers', value: 4 },
        { parent: 2, name: 'Tomatoes', value: 8 }
    ]
};

Note that in this data source, objects that have children have the "id" field whose value is unique. Their children have the "parent" field pointing at the parent's ID. The "id" and "parent" fields can have other names, but in any case, they must be assigned to the idField and parentField options.

var treeMapOptions = {
    // ...
    idField: 'id',
    parentField: 'parent'
};

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By default, the click, hoverChanged and selectionChanged events are fired for the tile that has been clicked, paused on or selected. If you need these events to be passed on to the parent group of the tile, set the interactWithGroup option to true. This setting impacts appearance as well. For example, when the user pauses on a tile, the whole group to which the tile belongs will apply the hover style.

Each tile or group of tiles is accompanied by a text label. Usually, a label displays the name of the tile or the group. However, you can put any desired text into it. For this purpose, call the label(label) method of the node whose label must be changed. You can call this method, for example, when all nodes are initialized or when they are being rendered.

If you need to change the appearance of all labels, use the tile.label and group.label objects. To change the appearance of a particular label, use the customize(options) function of the node to which the label belongs.

See Also

• dataSource - specifies the origin of data for the widget.
• valueField - specifies the data source field that provides values for tiles.
• childrenField - specifies the data source field that provides nested items for a group.

Layout algorithms determine the position and size of tiles and groups. Therefore, the chosen algorithm plays the definitive role in the resulting look of the widget. TreeMap provides the following algorithms out of the box.

• Squarified
  This algorithm lays the items out so that the aspect ratio will be closer to 1. In other words, this algorithm tries to make items as square as possible.

  For more information about this algorithm, refer to the Squarified Treemaps paper.

• Strip
  This algorithm is a modification of the "Squarified" algorithm. At the beginning, the algorithm has an available area divided into several strips and a set of items to distribute between the strips. Throughout the layout process, a current strip is maintained. For each item to be arranged, the algorithm checks whether or not adding the item to the current strip improves the average aspect ratios of the rectangles in the current strip. If so, the item is added to the current strip. Otherwise, it is added to the next strip.

  The direction of the strips depends on the size of the available area. If the width is greater than the height, the strips are lined up horizontally. If vice versa, vertically.

  For more information on this algorithm, see the Ordered and Quantum Treemaps: Making Effective Use of 2D Space to Display Hierarchies paper.

• Slice and Dice
  This algorithm uses parallel lines to divide an available area into rectangles representing items. In case of a hierarchical structure, each rectangle representing an item is divided once more into smaller rectangles representing its children, and so on.

  To learn more about this algorithm, refer to the Tree Visualization with Tree-Maps: a 2D Space-Filling Approach paper.

If none of the predefined algorithms satisfy your needs, implement your own algorithm. For this purpose, assign a function to the layoutAlgorithm option. Basically, this function should calculate the coordinates of two diagonally-opposite points defining a rectangle and assign them to the needed item. To access a set of items to distribute, use the items field of the function's parameter. All available fields of the parameter are listed in the header of this description.

var treeMapOptions = {
    // ...
    layoutAlgorithm: function (e) {
        // ...
        e.items.forEach(function(item) {
            // ...
            // Calculating the rectangle for the current item here
            // ...
            item.rect = rectPoints;
        });
    }
};

In addition, you can change the layout direction. For this purpose, use the layoutDirection option.

When using the widget as an ASP.NET MVC Control, you can specify this option using the TreeMapLayoutAlgorithm enum. This enum accepts the following values: Squarified, Strip and SliceAndDice.

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The value of this option determines the start and end point of the layout. See the image below to spot the difference between the available layout directions.

When using the widget as an ASP.NET MVC Control, you can specify this option using the TreeMapLayoutDirection enum. This enum accepts the following values: LeftTopRightBottom, LeftBottomRightTop, RightTopLeftBottom and RightBottomLeftTop.

When the widget visualizes local data, loading is instant. But when the widget is bound to a remote data source, loading may takes a considerable amount of time. To keep the viewer's attention, the widget can display a loading indicator.

To activate the loading indicator, assign true to the loadingIndicator.show option. Once data is loaded, the loading indicator will be hidden automatically.

See Also

• showLoadingIndicator()
• hideLoadingIndicator()

If you have a structure with deep nesting level, displaying all levels at once produces visual clutter. To reduce it, specify the number of levels that can be visualized at a time using the maxDepth property.

When you set this option, data that occupies the lowest levels may become unavailable to the user. For such cases, implement the drill down feature.

When implementing a handling function, use the object passed to it as the parameter. Among the fields of this object, you can find the clicked node. For example, the following function uses the node's select(state) and isSelected() methods to select/deselect the node on a click.

var treeMapOptions = {
    // ...
    onClick: function (e) {
        e.node.select(!e.node.isSelected());
    }
};

To identify whether the clicked node is a tile or a group of tiles, use the isLeaf() method. To learn about other available members of a node, refer to the description of the Node object.

Alternatively, you can navigate to a specific URL when the click event fires. For this purpose, assign this URL to the onClick option.

When implementing a handling function, use the object passed to it as the parameter. Among the fields of this object, you can find the currently displayed node. To learn about node's members that you can use, refer to the description of the Node object.

The onDrill event handler can be used to enable/disable other widgets bound to TreeMap. For example, consider that you have a Button. A click on it drills the TreeMap widget one level up from the current node. But when the root node becomes the current, there is nowhere to drill up. In that case, disable the button in the onDrill event handler.

var treeMapOptions = {
    // ...
    onDrill: function (e) {
        if (!e.node.getParent()) // checks whether the node has a parent; if it doesn't, it is the root node
            buttonInstance.option('disabled', true);
        else
            buttonInstance.option('disabled', false);
    };
};

Although not provided out-of-the-box, the drill down capability is easy to implement using the API methods. Learn how to do this from the drillDown() method description.

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See Also

• onExporting
• onFileSaving

See Also

• onExported
• onFileSaving

See Also

• onExporting
• onExported

When implementing a handling function, use the object passed to it as its parameter. Among the fields of this object, you can find the node whose hover state has been changed.

To identify whether the node was hovered over or hovered out, call its isHovered() method. To identify whether the node is a single tile or a group of tiles, call its isLeaf() method. Other accessible fields and methods of a node are described in the Node section.

When an error or warning appears, the widget notifies you by passing a message to the browser console. This message contains the ID of the incident, a brief description, and a link to the Errors and Warnings section where further information about this incident can be found. However, you can handle errors and warnings in the way that you require. To do this, implement a callback function performing the required actions and assign it to the onIncidentOccurred option. Within this function, you can use information about the incident that occurred. This information can be accessed from the target field of the object passed to the callback function as a parameter. This information includes the following.

• id
  Contains the ID of the incident. The full list of IDs can be found in the Errors and Warnings section.
• type
  Contains the type of the incident. This field equals "error" for errors or "warning" for warnings.
• args
  Contains the argument of the incident's message. The content of this field varies greatly, depending on the incident. For example, it may contain the name of the data source field that was not specified correctly, or the name of the option that was not set properly.
• text
  Contains the text passed to the browser console. This text includes the content of the args field, if there are any.
• widget
  Contains the name of the widget that produced the error or warning.
• version
  Contains the currently used version of the DevExtreme library.

You cannot access widget elements in this handler because it is executed before they are ready. Use the onDrawn handler instead.

Use this handler to perform certain operations on the node structure. It will be called once - at the beginning of the widget's lifetime.

Within the handler, you can use the object passed to it as the parameter. Among the fields of this object, you can find the root node. Using the getAllNodes(), getAllChildren() and getChild(index) methods of this node, you can access any other node in the widget. To learn about other available members of any node including the root node, refer to the description of the Node object.

Use this handler to customize nodes before they will be displayed. This handler will be called each time the collection of active nodes is changed.

Within the handler, you can use the object passed to it as the parameter. Among the fields of this object, you can find the currently displayed node. Using the getAllNodes(), getAllChildren(), getChild(index) and getParent() of this node, you can access any other node in the widget. To learn about other available members of any node, refer to the description of the Node object.

When implementing a handling function, use the object passed to it as its parameter. Among the fields of this object, you can find the node whose selection state has been changed.

To identify whether the node was selected or deselected, call its isSelected() method. To identify whether the node is a single tile or a group of tiles, call its isLeaf() method. Other accessible fields and methods of a node are described in the Node section.

In certain cases, you may have a plain data source that implies a hierarchical structure. For example, the following code declares a data source that, despite being plain, can be rearranged into a hierarchy of two groups with two items in each.

var treeMapOptions = {
    // ...
    dataSource: [
        // Group 1
        { id: 1, name: 'Fruits'},
        { parent: 1, name: 'Apples', value: 10 },
        { parent: 1, name: 'Oranges', value: 13 },

        // Group 2
        { id: 2, name: 'Vegetables' },
        { parent: 2, name: 'Cucumbers', value: 4 },
        { parent: 2, name: 'Tomatoes', value: 8 }
    ]
};

Note that in this data source, objects that have children have the "id" field whose value is unique. Their children have the "parent" field pointing at the parent's ID. The "id" and "parent" fields can have other names, but in any case they must be assigned to the idField and parentField options.

var treeMapOptions = {
    // ...
    idField: 'id',
    parentField: 'parent'
};

View Demo

If you place the widget on a page that uses a tag modifying the path (<base>, <iframe>, etc.), some of the widget elements may get mixed up or disappear. To solve this problem, set the pathModified option to true.

See Also

• DevExpress.viz.refreshPaths()

When this option is set to true, the widget will be redrawn automatically in case the size of its parent window changes.

When using the widget as an ASP.NET MVC Control, you can specify this option using the TreeMapResolveLabelOverflow enum. This enum accepts the following values: Hide and Ellipsis.

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When this option is set to true, the widget text flows from right to left, and the layout of elements is reversed. To switch the entire application/site to the right-to-left representation, assign true to the rtlEnabled field of the object passed to the DevExpress.config(config) method.

DevExpress.config({
    rtlEnabled: true
});

In a single mode, only one node can be in the selected state at one moment. When the user selects another node, the formerly selected node becomes unselected. In a multiple mode, any number of nodes can be in the selected state.

To implement selection, assign the following or similar callback function to the onClick option.

var treeMapOptions = {
    // ...
    onClick: function (e) {
        e.node.select(!e.node.isSelected());
    }    
};

When entering the selected state, a tile or a group of tiles changes its appearance. You can configure it using the group | selectionStyle and tile.selectionStyle objects.

To control the selection feature in code, use the isSelected, select(state) and clearSelection() methods. In addition, you can perform certain actions when a node enters/leaves the selected state. For this purpose, implement the onSelectionChanged event handler.

When using the widget as an ASP.NET MVC Control, specify this option using the SelectionMode enum. This enum accepts the following values: None, Single and Multiple.

The widget occupies its container's entire area by default. Use the size object to specify the widget's size if it should be different from that of its container. Assign 0 to size object's height and width options to hide the widget.

A theme is a widget configuration that gives the widget a distinctive appearance. Use can use one of the predefined themes or create a custom one. Changing the option values in the widget's configuration object overrides the theme's corresponding values.

When using the widget as an ASP.NET MVC Control, specify this option using the VizTheme enum. This enum accepts the following values: GenericLight, GenericDark, GenericContrast, GenericCarmine, GenericDarkMoon, GenericSoftBlue, GenericDarkViolet, GenericGreenMist, Android5Light, IOS7Default, Win10Black and Win10White.

A tile is a rectangle representing a node that has no children in the current context. Several tiles can be collected into a group if the data source implies a hierarchical structure.

The following list provides an overview of tiles' features that you can configure using the tile object.

• Labels
  Each tile is identified by a label. Its appearance can be changed using the fields of the label object. If the tile's area is too small, the label will be hidden.
• Color
  There are several approaches to colorizing the tiles. Refer to the color option description to find information about all of them.
• Hover and Selection Styles
  A tile can be in the hover or selected state. In these states, its style changes to the one specified by the hoverStyle or selectionStyle object respectively. Along with the tile, its parent group can enter the hover or selected state. To enable this feature, assign true to the interactWithGroup option of the root configuration object.
• Border's Appearance
  Specify the fields of the border object to configure the tile borders.

An object assigned to the tile field configures all tiles in the widget. To customize a specific tile, pass a similar object to the customize(options) method of the node represented by the tile.

The widget's title is a short text that usually indicates what is visualized. If you need to specify the title's text only, assign it directly to the title option. Otherwise, set this option to an object with the text and other fields specified.

The title can be accompanied by a subtitle elaborating on the visualized subject using the title.subtitle object.

See Also

• dataSource - specifies the origin of data for the widget.
• childrenField - specifies the data source field that provides nested items for a group.
• labelField - specifies the data source field that provides texts for tile and group labels.