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Interface: StyleImageInterface

Interface for dynamically generated style images. This is a specification for implementers to model: it is not an exported method or class.

Images implementing this interface can be redrawn for every frame. They can be used to animate icons and patterns or make them respond to user input. Style images can implement a StyleImageInterface#render method. The method is called every frame and can be used to update the image.

See

Add an animated icon to the map.

Example

let flashingSquare = {
    width: 64,
    height: 64,
    data: new Uint8Array(64 * 64 * 4),

    onAdd: function(map) {
        this.map = map;
    },

    render: function() {
        // keep repainting while the icon is on the map
        this.map.triggerRepaint();

        // alternate between black and white based on the time
        let value = Math.round(Date.now() / 1000) % 2 === 0  ? 255 : 0;

        // check if image needs to be changed
        if (value !== this.previousValue) {
            this.previousValue = value;

            let bytesPerPixel = 4;
            for (let x = 0; x < this.width; x++) {
                for (let y = 0; y < this.height; y++) {
                    let offset = (y * this.width + x) * bytesPerPixel;
                    this.data[offset + 0] = value;
                    this.data[offset + 1] = value;
                    this.data[offset + 2] = value;
                    this.data[offset + 3] = 255;
                }
            }

            // return true to indicate that the image changed
            return true;
        }
    }
 }

 map.addImage('flashing_square', flashingSquare);

Properties

onAdd

Optional onAdd: (map: Map, id: string) => void

Optional method called when the layer has been added to the Map with Map#addImage.

Type declaration

▸ (map, id): void

Parameters
Name Type Description
map Map The Map this custom layer was just added to.
id string -
Returns

void

Defined in

src/style/style_image.ts:141


onRemove

Optional onRemove: () => void

Optional method called when the icon is removed from the map with Map#removeImage. This gives the image a chance to clean up resources and event listeners.

Type declaration

▸ (): void

Returns

void

Defined in

src/style/style_image.ts:146


render

Optional render: () => boolean

This method is called once before every frame where the icon will be used. The method can optionally update the image's data member with a new image.

If the method updates the image it must return true to commit the change. If the method returns false or nothing the image is assumed to not have changed.

If updates are infrequent it maybe easier to use Map#updateImage to update the image instead of implementing this method.

Type declaration

▸ (): boolean

Returns

boolean

Defined in

src/style/style_image.ts:135