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@deck.gl/layers

IconLayer

The Icon Layer renders raster icons at given coordinates.

There are two approaches to load icons. You can pre-generated a sprite image (iconAtlas), which packs all your icons into one layout, and a JSON descriptor (iconMapping), which describes the position and size of each icon in the iconAtlas. You can create sprite images with tools such as TexturePacker. This is the most efficient way to load icons.

It is also possible to ask IconLayer to generate iconAtlas dynamically. This is slower but might be useful in certain use cases.

Example: pre-packed iconAtlas

import DeckGL from '@deck.gl/react';
import {IconLayer} from '@deck.gl/layers';

const ICON_MAPPING = {
  marker: {x: 0, y: 0, width: 32, height: 32, mask: true}
};

const App = ({data, viewport}) => {

  /**
   * Data format:
   * [
   *   {name: 'Colma (COLM)', address: '365 D Street, Colma CA 94014', exits: 4214, coordinates: [-122.466233, 37.684638]},
   *   ...
   * ]
   */
  const layer = new IconLayer({
    id: 'icon-layer',
    data,
    pickable: true,
    // iconAtlas and iconMapping are required
    // getIcon: return a string
    iconAtlas: 'images/icon-atlas.png',
    iconMapping: ICON_MAPPING,
    getIcon: d => 'marker',

    sizeScale: 15,
    getPosition: d => d.coordinates,
    getSize: d => 5,
    getColor: d => [Math.sqrt(d.exits), 140, 0],
    onHover: ({object, x, y}) => {
      const tooltip = `${object.name}\n${object.address}`;
      /* Update tooltip
         http://deck.gl/#/documentation/developer-guide/adding-interactivity?section=example-display-a-tooltip-for-hovered-object
      */
    }
  });

  return (<DeckGL {...viewport} layers={[layer]} />);
};

Example: auto packing iconAtlas

In some use cases, it is not possible to know the icons that will be used. Instead, each icon needs to be fetched from a programmatically generated URL at runtime. For example, if you want to visualize avatars of github contributors for a project on a map, it is not convenient for you to generate the iconAtlas with all the contributors' avatars. In this case, you can follow the example. Auto packing icons is less efficient than pre-packed.

import DeckGL, {IconLayer} from 'deck.gl';
import Octokit from '@octokit/rest';
const octokit = new Octokit()

const App = ({data, viewport}) => {

  /**
   * Data format:
   * [
   *   {
   *     avatar_url: "https://avatars1.githubusercontent.com/u/7025232?v=4",
   *     contributions: 620,
   *     id: 7025232,
   *     login: "ibgreen",
   *     type: "User",
   *     ...
   *   }
   * ]
   */
  const layer = new IconLayer({
    id: 'icon-layer',
    data: octokit.repos.getContributors({
      owner: 'uber',
      repo: 'deck.gl'
    }).then(result => result.data),
    // iconAtlas and iconMapping should not be provided
    // getIcon return an object which contains url to fetch icon of each data point
    getIcon: d => ({
      url: d.avatar_url,
      width: 128,
      height: 128,
      anchorY: 128
    }),
    // icon size is based on data point's contributions, between 2 - 25
    getSize: d => Math.max(2, Math.min(d.contributions / 1000 * 25, 25)),
    pickable: true,
    sizeScale: 15,
    getPosition: d => d.coordinates,
    onHover: ({object, x, y}) => {
      const tooltip = `${object.login}\n${object.contributions}`;
      /* Update tooltip
         http://deck.gl/#/documentation/developer-guide/adding-interactivity?section=example-display-a-tooltip-for-hovered-object
      */
    }
  });

  return (<DeckGL {...viewport} layers={[layer]} />);
};

Installation

To install the dependencies from NPM:

npm install deck.gl
# or
npm install @deck.gl/core @deck.gl/layers
import {IconLayer} from '@deck.gl/layers';
new IconLayer({});

To use pre-bundled scripts:

<script src="https://unpkg.com/deck.gl@^8.0.0/dist.min.js"></script>
<!-- or -->
<script src="https://unpkg.com/@deck.gl/core@^8.0.0/dist.min.js"></script>
<script src="https://unpkg.com/@deck.gl/layers@^8.0.0/dist.min.js"></script>
new deck.IconLayer({});

Properties

Inherits from all Base Layer properties.

iconAtlas (Texture2D | String)

Atlas image url or texture

iconMapping (Object | String)

Icon names mapped to icon definitions. Each icon is defined with the following values:

  • x (Number, required): x position of icon on the atlas image
  • y (Number, required): y position of icon on the atlas image
  • width (Number, required): width of icon on the atlas image
  • height (Number, required): height of icon on the atlas image
  • anchorX (Number, optional): horizontal position of icon anchor. Default: half width.
  • anchorY (Number, optional): vertical position of icon anchor. Default: half height.
  • mask (Boolean, optional): whether icon is treated as a transparency mask. If true, user defined color is applied. If false, pixel color from the image is applied. User still can specify the opacity through getColor. Default: false

If you go with pre-packed strategy, both iconAtlas and iconMapping are required.

If you choose to use auto packing, then iconAtlas and iconMapping should not be provided, otherwise it causes error since IconLayer will attempt to retrieve icons from given pre-packed iconAtlas.

sizeScale (Number, optional) transition-enabled
  • Default: 1

Icon size multiplier.

sizeUnits (String, optional)
  • Default: pixels

The units of the size specified by getSize, one of 'meters', 'pixels'. When zooming in and out, meter sizes scale with the base map, and pixel sizes remain the same on screen.

sizeMinPixels (Number, optional) transition-enabled
  • Default: 0

The minimum size in pixels.

sizeMaxPixels (Number, optional) transition-enabled
  • Default: Number.MAX_SAFE_INTEGER

The maximum size in pixels.

billboard (Boolean, optional)
  • Default: true

If on, the icon always faces camera. Otherwise the icon faces up (z)

alphaCutoff (Number, optional)
  • Default: 0.05

Discard pixels whose opacity is below this threshold. A discarded pixel would create a "hole" in the icon that is not considered part of the object. This is useful for customizing picking behavior, e.g. setting alphaCutoff: 0, autoHighlight will highlight an object whenever the cursor moves into its bounding box, instead of over the visible pixels.

Data Accessors

getIcon (Function, optional)
  • Default: d => d.icon

Method called to retrieve the icon name of each object, returns string or object.

If you go with pre-packed strategy, then getIcon should return a string representing name of the icon, used to retrieve icon definition from given iconMapping.

If you choose to use auto packing, then getIcon should return an object which contains the following properties.

  • url (String, required): url to fetch the icon
  • height (Number, required): height of icon
  • width (Number, required): width of icon
  • id: (String, optional): unique identifier of the icon, fall back to url if not specified
  • anchorX, anchorY, mask are the same as mentioned in iconMapping

IconLayer use id (fallback to url) to dedupe icons. If for the same icon identifier, getIcon returns different width or height, IconLayer will only apply the first occurrence and ignore the rest of them.

getPosition (Function, optional) transition-enabled
  • Default: d => d.position

Method called to retrieve the position of each object, returns [lng, lat, z].

getSize (Function|Number, optional) transition-enabled
  • Default: 1

The height of each object, in units specified by sizeUnits (default pixels).

  • If a number is provided, it is used as the size for all objects.
  • If a function is provided, it is called on each object to retrieve its size.
getColor (Function|Array, optional) transition-enabled
  • Default: [0, 0, 0, 255]

The rgba color is in the format of [r, g, b, [a]]. Each channel is a number between 0-255 and a is 255 if not supplied.

  • If an array is provided, it is used as the color for all objects.
  • If a function is provided, it is called on each object to retrieve its color.
  • If mask = false, only the alpha component will be used to control the opacity of the icon.
getAngle (Function|Number, optional) transition-enabled
  • Default: 0

The rotating angle of each object, in degrees.

  • If a number is provided, it is used as the angle for all objects.
  • If a function is provided, it is called on each object to retrieve its angle.

Use binary attributes

This section is about the special requirements when supplying attributes directly to an IconLayer.

If data.attributes.getIcon is supplied, since its value can only be a typed array, iconMapping can only use integers as keys.

Source

modules/layers/src/icon-layer

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