import { EventEmitter } from '@angular/core';
import { Observable, ObservableInput } from 'rxjs';
export declare type StateChange = {
    reason: 'setup' | 'observer-emit' | 'start-loading' | 'mount-image' | 'loading-failed' | 'loading-succeeded' | 'finally';
    data?: unknown;
};
export declare type Attributes<T = any> = {
    /**
     * A reference to the element
     */
    element: HTMLImageElement | HTMLDivElement;
    /**
     * A URI path to the image to be lazyloaded
     */
    imagePath: string;
    /**
     * A URI path to the default image
     */
    defaultImagePath?: string;
    /**
     * A URI path to the error image
     */
    errorImagePath?: string;
    /**
     * If true, use a `srcset` for the image
     */
    useSrcset?: boolean;
    /**
     * Number of pixels to use as offset in all directions
     */
    offset: number;
    /**
     * A reference to the scroll container, if not window
     */
    scrollContainer?: HTMLElement;
    /**
     * A custom customObservable.
     */
    customObservable?: Observable<T>;
    /**
     * If true, try to decode the image before put it to the DOM
     */
    decode?: boolean;
    /**
     * If true, try to decode the image before put it to the DOM
     */
    onStateChange: EventEmitter<StateChange>;
    /**
     * A uniq id for the image
     */
    id: string;
};
export declare abstract class Hooks<E = unknown> {
    navigator?: Navigator;
    protected platformId: Object;
    setPlatformId(platformId: Object): void;
    abstract getObservable(attributes: Attributes): Observable<E>;
    abstract isVisible(event: E, attributes: Attributes): boolean;
    abstract loadImage(attributes: Attributes): ObservableInput<string>;
    abstract setLoadedImage(imagePath: string, attributes: Attributes): void;
    abstract setErrorImage(error: Error, attributes: Attributes): void;
    abstract setup(attributes: Attributes): void;
    abstract finally(attributes: Attributes): void;
    abstract isBot(attributes?: Attributes): boolean;
    abstract isDisabled(): boolean;
    abstract skipLazyLoading(attributes: Attributes): boolean;
    onDestroy(attributes: Attributes): void;
    onAttributeChange(newAttributes: Attributes): void;
}