IconLayer

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The IconLayer 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: 128, height: 128, mask: true}
};

function App({data, viewState}) {
  /**
   * 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: 'https://raw.githubusercontent.com/visgl/deck.gl-data/master/website/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]
  });

  return <DeckGL viewState={viewState}
    layers={[layer]}
    getTooltip={({object}) => object && `${object.name}\n${object.address}`} />;
}

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()

function App({data, viewState}) {
  /**
   * 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: 'visgl',
      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
  });

  return <DeckGL viewState={viewState}
    layers={[layer]}
    getTooltip={({object}) => object && `${object.login}\n${object.contributions}`} />;
}

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 (String|Texture|Image|ImageData|HTMLCanvasElement|HTMLVideoElement|ImageBitmap|Promise|Object, optional)

A pre-packed image that contains all icons.

• If a string is supplied, it is interpreted as a URL or a Data URL.
• One of the following, or a Promise that resolves to one of the following:
  • One of the valid pixel sources for WebGL2 texture
  • A luma.gl Texture instance
  • A plain object that can be passed to the Texture constructor, e.g. {width: <number>, height: <number>, data: <Uint8Array>}. Note that whenever this object shallowly changes, a new texture will be created.

The image data will be converted to a Texture object. See textureParameters prop for advanced customization.

If you go with pre-packed strategy, this prop is required.

If you choose to use auto packing, this prop should be left empty.

iconMapping (Object|String, optional)

Icon names mapped to icon definitions, or a URL to load such mapping from a JSON file. 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, this prop is required.

If you choose to use auto packing, this prop should be left empty.

sizeScale (Number, optional)

• Default: 1

Icon size multiplier.

sizeUnits (String, optional)

• Default: pixels

The units of the size, one of 'meters', 'common', and 'pixels'. See unit system.

sizeMinPixels (Number, optional)

• Default: 0

The minimum size in pixels. When using non-pixel sizeUnits, this prop can be used to prevent the icon from getting too small when zoomed out.

sizeMaxPixels (Number, optional)

• Default: Number.MAX_SAFE_INTEGER

The maximum size in pixels. When using non-pixel sizeUnits, this prop can be used to prevent the icon from getting too big when zoomed in.

billboard (Boolean, optional)

• Default: true

If true, 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.

loadOptions (Object, optional)

On top of the default options, also accepts options for the following loaders:

• ImageLoader if the iconAtlas prop is an URL, or if getIcon returns URLs for auto-packing

textureParameters (Object)

Customize the texture parameters.

If not specified, the layer uses the following defaults to create a linearly smoothed texture from iconAtlas:

{
  minFilter: 'linear',
  magFilter: 'linear',
  mipmapFilter: 'linear',
  addressModeU: 'clamp-to-edge',
  addressModeV: 'clamp-to-edge'
}

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): max height of icon
• width (Number, required): max 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 uses id (fallback to url) to dedupe icons. For icons with the same id, even if their sizes differ, IconLayer will only define one icon according to the first occurrence and ignore the rest of them. Vice versa, for icons with different ids, even if urls are the same, the image will be fetched again to create a new definition with different size, anchor, etc.

The image loaded from url is always resized to fit the box defined by [width, height] while preserving its aspect ratio.

getPosition (Function, optional)

• Default: d => d.position

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

getSize (Function|Number, optional)

• 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)

• 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)

• 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.

getPixelOffset (Function|Array, optional)

• Default: [0, 0]

Screen space offset relative to the coordinates in pixel unit.

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

Callbacks

onIconError (Function)

• Default: null

Only used when using auto-packing. If the attempt to fetch an icon returned by getIcon fails, this callback is called with the following arguments:

• event (Object)
  • url (String) - the URL that was trying to fetch
  • loadOptions (Object) - the load options used for the fetch
  • source (Object) - the original data object that requested this icon
  • sourceIndex (Object) - the index of the original data object that requested this icon
  • error (Error)

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