Highlight data points in Power BI Visuals

By default whenever an element is selected the values array in the dataView object will be filtered to just the selected values. It will cause all other visuals on the page to display just the selected data.

highlight dataview default behavior

If you set the supportsHighlight property in your capabilities.json to true, you'll receive the full unfiltered values array along with a highlights array. The highlights array will be the same length as the values array and any non-selected values will be set to null. With this property enabled it's the visual's responsibility to highlight the appropriate data by comparing the values array to the highlights array.

dataview supports highlight

In the example, you'll notice that 1 bar is selected. And it's the only value in the highlights array. It's also important to note that there could be multiple selections and partial highlights. The highlighted values will be presented in the data view.

Note

Table data view mapping doesn't support the highlights feature.

Highlight data points with categorical data view mapping

The visuals with categorical data view mapping have capabilities.json with "supportsHighlight": true parameter. For example:

{
    "dataRoles": [
        {
            "displayName": "Category",
            "name": "category",
            "kind": "Grouping"
        },
        {
            "displayName": "Value",
            "name": "value",
            "kind": "Measure"
        }
    ],
    "dataViewMappings": [
        {
            "categorical": {
                "categories": {
                    "for": {
                        "in": "category"
                    }
                },
                "values": {
                    "for": {
                        "in": "value"
                    }
                }
            }
        }
    ],
    "supportsHighlight": true
}

The default visual source code after removing unnecessary code will look like this:

"use strict";

// ... default imports list

import DataViewCategorical = powerbi.DataViewCategorical;
import DataViewCategoryColumn = powerbi.DataViewCategoryColumn;
import PrimitiveValue = powerbi.PrimitiveValue;
import DataViewValueColumn = powerbi.DataViewValueColumn;

import { VisualSettings } from "./settings";

export class Visual implements IVisual {
    private target: HTMLElement;
    private settings: VisualSettings;

    constructor(options: VisualConstructorOptions) {
        console.log('Visual constructor', options);
        this.target = options.element;
        this.host = options.host;

    }

    public update(options: VisualUpdateOptions) {
        this.settings = Visual.parseSettings(options && options.dataViews && options.dataViews[0]);
        console.log('Visual update', options);

    }

    private static parseSettings(dataView: DataView): VisualSettings {
        return <VisualSettings>VisualSettings.parse(dataView);
    }

    /**
     * This function gets called for each of the objects defined in the capabilities files and allows you to select which of the
     * objects and properties you want to expose to the users in the property pane.
     *
     */
    public enumerateObjectInstances(options: EnumerateVisualObjectInstancesOptions): VisualObjectInstance[] | VisualObjectInstanceEnumerationObject {
        return VisualSettings.enumerateObjectInstances(this.settings || VisualSettings.getDefault(), options);
    }
}

Import required interfaces to process data from Power BI:

import DataViewCategorical = powerbi.DataViewCategorical;
import DataViewCategoryColumn = powerbi.DataViewCategoryColumn;
import PrimitiveValue = powerbi.PrimitiveValue;
import DataViewValueColumn = powerbi.DataViewValueColumn;

Create root div element for category values:

export class Visual implements IVisual {
    private target: HTMLElement;
    private settings: VisualSettings;

    private div: HTMLDivElement; // new property

    constructor(options: VisualConstructorOptions) {
        console.log('Visual constructor', options);
        this.target = options.element;
        this.host = options.host;

        // create div element
        this.div = document.createElement("div");
        this.div.classList.add("vertical");
        this.target.appendChild(this.div);

    }
    // ...
}

Clear content of div elements before rendering new data:

// ...
public update(options: VisualUpdateOptions) {
    this.settings = Visual.parseSettings(options && options.dataViews && options.dataViews[0]);
    console.log('Visual update', options);

    while (this.div.firstChild) {
        this.div.removeChild(this.div.firstChild);
    }
    // ...
}

Get categories and measure values from dataView object:

public update(options: VisualUpdateOptions) {
    this.settings = Visual.parseSettings(options && options.dataViews && options.dataViews[0]);
    console.log('Visual update', options);

    while (this.div.firstChild) {
        this.div.removeChild(this.div.firstChild);
    }

    const dataView: DataView = options.dataViews[0];
    const categoricalDataView: DataViewCategorical = dataView.categorical;
    const categories: DataViewCategoryColumn = categoricalDataView.categories[0];
    const categoryValues = categories.values;

    const measures: DataViewValueColumn = categoricalDataView.values[0];
    const measureValues = measures.values;
    const measureHighlights = measures.highlights;
    // ...
}

Where categoryValues is an array of category values, measureValues is an array of measures, and measureHighlights is highlighted parts of values.

Note

Values of measureHighlights property can be less that values of categoryValues property. In means that value was higlighted partially.

Enumerate categoryValues array and get corresponding values and highlights:

// ...
const measureHighlights = measures.highlights;

categoryValues.forEach((category: PrimitiveValue, index: number) => {
    const measureValue = measureValues[index];
    const measureHighlight = measureHighlights && measureHighlights[index] ? measureHighlights[index] : null;
    console.log(category, measureValue, measureHighlight);

});

Create div and p elements to display and visualize data view values in visual DOM:

categoryValues.forEach((category: PrimitiveValue, index: number) => {
    const measureValue = measureValues[index];
    const measureHighlight = measureHighlights && measureHighlights[index] ? measureHighlights[index] : null;
    console.log(category, measureValue, measureHighlight);

    // div element. it contains elements to display values and visualize value as progress bar
    let div = document.createElement("div");
    div.classList.add("horizontal");
    this.div.appendChild(div);

    // div element to vizualize value of measure
    let barValue = document.createElement("div");
    barValue.style.width = +measureValue * 10 + "px";
    barValue.style.display = "flex";
    barValue.classList.add("value");

    // element to display category value
    let bp = document.createElement("p");
    bp.innerText = category.toString();

    // div element to vizualize highlight of measure
    let barHighlight = document.createElement("div");
    barHighlight.classList.add("highlight")
    barHighlight.style.backgroundColor = "blue";
    barHighlight.style.width = +measureHighlight * 10 + "px";

    // element to display highlighted value of measure
    let p = document.createElement("p");
    p.innerText = `${measureHighlight}/${measureValue}`;
    barHighlight.appendChild(bp);

    div.appendChild(barValue);

    barValue.appendChild(barHighlight);
    div.appendChild(p);
});

Apply required styles for elements to use flex box and define colors for div elements:

div.vertical {
    display: flex;
    flex-direction: column;
}

div.horizontal {
    display: flex;
    flex-direction: row;
}

div.highlight {
    background-color: blue
}

div.value {
    background-color: red;
    display: flex;
}

In the result, you should have the following view of the visual.

The visuals with categorical data view mapping and highlight

Highlight data points with matrix data view mapping

The visuals with matrix data view mapping have capabilities.json with "supportsHighlight": true parameter. For example:

{
    "dataRoles": [
        {
            "displayName": "Columns",
            "name": "columns",
            "kind": "Grouping"
        },
        {
            "displayName": "Rows",
            "name": "rows",
            "kind": "Grouping"
        },
        {
            "displayName": "Value",
            "name": "value",
            "kind": "Measure"
        }
    ],
    "dataViewMappings": [
        {
            "matrix": {
                "columns": {
                    "for": {
                        "in": "columns"
                    }
                },
                "rows": {
                    "for": {
                        "in": "rows"
                    }
                },
                "values": {
                    "for": {
                        "in": "value"
                    }
                }
            }
        }
    ],
    "supportsHighlight": true
}

The sample data to create hierarchy for matrix data view mapping:

Row1 Row2 Row3 Column1 Column2 Column3 Values
R1 R11 R111 C1 C11 C111 1
R1 R11 R112 C1 C11 C112 2
R1 R11 R113 C1 C11 C113 3
R1 R12 R121 C1 C12 C121 4
R1 R12 R122 C1 C12 C122 5
R1 R12 R123 C1 C12 C123 6
R1 R13 R131 C1 C13 C131 7
R1 R13 R132 C1 C13 C132 8
R1 R13 R133 C1 C13 C133 9
R2 R21 R211 C2 C21 C211 10
R2 R21 R212 C2 C21 C212 11
R2 R21 R213 C2 C21 C213 12
R2 R22 R221 C2 C22 C221 13
R2 R22 R222 C2 C22 C222 14
R2 R22 R223 C2 C22 C223 16
R2 R23 R231 C2 C23 C231 17
R2 R23 R232 C2 C23 C232 18
R2 R23 R233 C2 C23 C233 19

Create the default visual project and apply sample of capabilities.json.

Default visual source code after removing unessesray code will look:

"use strict";

// ... default imports

import { VisualSettings } from "./settings";

export class Visual implements IVisual {
    private target: HTMLElement;
    private settings: VisualSettings;


    constructor(options: VisualConstructorOptions) {
        console.log('Visual constructor', options);
        this.target = options.element;
        this.host = options.host;
    }

    public update(options: VisualUpdateOptions) {
        this.settings = Visual.parseSettings(options && options.dataViews && options.dataViews[0]);
        console.log('Visual update', options);

    }

    private static parseSettings(dataView: DataView): VisualSettings {
        return <VisualSettings>VisualSettings.parse(dataView);
    }

    /**
     * This function gets called for each of the objects defined in the capabilities files and allows you to select which of the
     * objects and properties you want to expose to the users in the property pane.
     *
     */
    public enumerateObjectInstances(options: EnumerateVisualObjectInstancesOptions): VisualObjectInstance[] | VisualObjectInstanceEnumerationObject {
        return VisualSettings.enumerateObjectInstances(this.settings || VisualSettings.getDefault(), options);
    }
}

Import required interfaces to process data from Power BI:

import DataViewMatrix = powerbi.DataViewMatrix;
import DataViewMatrixNode = powerbi.DataViewMatrixNode;
import DataViewHierarchyLevel = powerbi.DataViewHierarchyLevel;

Create two div elements for visual layout:

constructor(options: VisualConstructorOptions) {
    // ...
    this.rowsDiv = document.createElement("div");
    this.target.appendChild(this.rowsDiv);

    this.colsDiv = document.createElement("div");
    this.target.appendChild(this.colsDiv);
    this.target.style.overflowY = "auto";
}

Check the data in update method, to ensure that visual gets data:

public update(options: VisualUpdateOptions) {
    this.settings = Visual.parseSettings(options && options.dataViews && options.dataViews[0]);
    console.log('Visual update', options);

    const dataView: DataView = options.dataViews[0];
    const matrixDataView: DataViewMatrix = dataView.matrix;

    if (!matrixDataView ||
        !matrixDataView.columns ||
        !matrixDataView.rows ) {
        return
    }
    // ...
}

Clear content of div elements before render new data:

public update(options: VisualUpdateOptions) {
    // ...

    // remove old elements
    // to better performance use D3js pattern:
    // https://d3js.org/#enter-exit
    while (this.rowsDiv.firstChild) {
        this.rowsDiv.removeChild(this.rowsDiv.firstChild);
    }
    const prow = document.createElement("p");
    prow.innerText = "Rows";
    this.rowsDiv.appendChild(prow);

    while (this.colsDiv.firstChild) {
        this.colsDiv.removeChild(this.colsDiv.firstChild);
    }
    const pcol = document.createElement("p");
    pcol.innerText = "Columns";
    this.colsDiv.appendChild(pcol);
    // ...
}

Create treeWalker function to traverse matrix data structure:

public update(options: VisualUpdateOptions) {
    // ...
    const treeWalker = (matrixNode: DataViewMatrixNode, index: number, levels: DataViewHierarchyLevel[], div: HTMLDivElement)  => {

    }
    // ...
}

Where matrixNode is the current node, levels is metadata columns of this hierarchy level, div - parent element for child HTML elements.

The treeWalker is recursive function, need to create div element and p for text as header, and call the function for child elements of node:

public update(options: VisualUpdateOptions) {
    // ...
    const treeWalker = (matrixNode: DataViewMatrixNode, index: number, levels: DataViewHierarchyLevel[], div: HTMLDivElement)  => {
        // ...

        if (matrixNode.children) {
            const childDiv = document.createElement("div");
            childDiv.classList.add("vertical");
            div.appendChild(childDiv);

            const p = document.createElement("p");
            const level = levels[matrixNode.level]; // get current level column metadata from current node
            p.innerText = level.sources[level.sources.length - 1].displayName; // get column name from metadata

            childDiv.appendChild(p); // add paragraph element to div element
            matrixNode.children.forEach((node, index) => treeWalker(node, levels, childDiv, ++levelIndex));
        }
    }
    // ...
}

Call the function for root elements of column and row of matrix data view structure:

public update(options: VisualUpdateOptions) {
    // ...
    const treeWalker = (matrixNode: DataViewMatrixNode, index: number, levels: DataViewHierarchyLevel[], div: HTMLDivElement)  => {
        // ...
    }
    // ...
    // remove old elements
    // ...

    // ...
    const rowRoot: DataViewMatrixNode = matrixDataView.rows.root;
    rowRoot.children.forEach((node) => treeWalker(node, matrixDataView.rows.levels, this.rowsDiv));

    const colRoot = matrixDataView.columns.root;
    colRoot.children.forEach((node) => treeWalker(node, matrixDataView.columns.levels, this.colsDiv));
}

Generate selectionID for nodes and Create buttons to display nodes:

public update(options: VisualUpdateOptions) {
    // ...
    const treeWalker = (matrixNode: DataViewMatrixNode, index: number, levels: DataViewHierarchyLevel[], div: HTMLDivElement)  => {
        const selectionID: ISelectionID = this.host.createSelectionIdBuilder()
            .withMatrixNode(matrixNode, levels)
            .createSelectionId();

        let nodeBlock = document.createElement("button");
        nodeBlock.innerText = matrixNode.value.toString();

        nodeBlock.addEventListener("click", (event) => {
            // call select method in the selection manager
            this.selectionManager.select(selectionID);
        });

        nodeBlock.addEventListener("contextmenu", (event) => {
            // call showContextMenu method to display context menu on the visual
            this.selectionManager.showContextMenu(selectionID, {
                x: event.clientX,
                y: event.clientY
            });
            event.preventDefault();
        });
        // ...
    }
    // ...
}

The main step of using highlighting is to process additional array of values.

If you inspect the object of terminal node, you can see that the values array has two properties - value and highlight:

JSON.stringify(options.dataViews[0].matrix.rows.root.children[0].children[0].children[0], null, " ");
{
 "level": 2,
 "levelValues": [
  {
   "value": "R233",
   "levelSourceIndex": 0
  }
 ],
 "value": "R233",
 "identity": {
  "identityIndex": 2
 },
 "values": {
  "0": {
   "value": null,
   "highlight": null
  },
  "1": {
   "value": 19,
   "highlight": 19
  }
 }
}

Where value property represents value of node without applying a selection from other visual, and highlight property indicates which part of data was highlighted.

Note

Value of highlight property can be less that value of value property. In means that value was higlighted partially.

Add the code to process the values array of node if it is presented:

public update(options: VisualUpdateOptions) {
    // ...
    const treeWalker = (matrixNode: DataViewMatrixNode, index: number, levels: DataViewHierarchyLevel[], div: HTMLDivElement)  => {
        // ...

        if (matrixNode.values) {
            const sumOfValues = Object.keys(matrixNode.values) // get key property of object (value are 0 to N)
                .map(key => +matrixNode.values[key].value) // convert key property to number
                .reduce((prev, curr) => prev + curr) // sum of values

            let sumOfHighlights = sumOfValues;
            sumOfHighlights = Object.keys(matrixNode.values) // get key property of object (value are 0 to N)
                .map(key => matrixNode.values[key].highlight ? +matrixNode.values[key].highlight : null ) // convert key property to number if it exists
                .reduce((prev, curr) => curr ? prev + curr : null) // convert key property to number

            // create div container for value and highlighted value
            const vals = document.createElement("div");
            vals.classList.add("vertical")
            vals.classList.replace("vertical", "horizontal");
            // create paragraph element for label
            const highlighted = document.createElement("p");
            // Display complete value and highlighted value
            highlighted.innerText = `${sumOfHighlights}/${sumOfValues}`;

            // create div container for value
            const valueDiv = document.createElement("div");
            valueDiv.style.width = sumOfValues * 10 + "px";
            valueDiv.classList.add("value");

            // create div container for highlighted values
            const highlightsDiv = document.createElement("div");
            highlightsDiv.style.width = sumOfHighlights * 10 + "px";
            highlightsDiv.classList.add("highlight");
            valueDiv.appendChild(highlightsDiv);

            // append button and paragraph to div containers to parent div
            vals.appendChild(nodeBlock);
            vals.appendChild(valueDiv);
            vals.appendChild(highlighted);
            div.appendChild(vals);
        } else {
            div.appendChild(nodeBlock);
        }

        if (matrixNode.children) {
            // ...
        }
    }
    // ...
}

As the result you'll get the visual with buttons and values highlighted value/default value

The visual with matrix data views mapping and highlight

Next steps