/**
 * @module plugins
 */
/**
 * Callback interface for handling the scroll event
 *
 * ```typescript
 * const onZoom = (scaleDiff: number) => {
 *     panHandler.incrementZoom(scaleDiff);
 *     clearAndDraw();
 * }
 * ```
 */
export declare type OnZoom = (delta: number) => void;
/**
 * A simple scroll to zoom handler
 *
 * ```typescript
 * import { PanHandler } from 'pan-handler/PanHandler.js';
 * import { ScrollZoom } from 'pan-handler/plugins/ScrollZoom.js';
 *
 * const ctx = document.getElementById('myCanvas').getContext('2d');
 * const panHandler = new PanHandler(ctx, PAN_OPTIONS);
 *
 * const clearAndDraw = () => {
 *     panHandler.clear();
 *     // Your draw logic here...
 * };
 *
 * const scrollZoom = new ScrollZoom((scaleDiff) => {
 *     panHandler.incrementZoom(scaleDiff);
 *     clearAndDraw();
 * });
 * scrollZoom.addTarget(ctx.canvas);
 * ```
 */
export declare class ScrollZoom {
    private onZoom;
    constructor(onZoom: OnZoom);
    /**
     * Attach wheel handlers to an element. When that element is mousewheeled
     * the [[OnZoom]] callback will fire
     *
     * You may call `addTarget` multiple times with different elements to attach
     * handlers to multiple elements.
     */
    addTarget(target: HTMLElement): void;
    private handleScroll;
}