Files
openlayers/src/ol/interaction/KeyboardZoom.js

97 lines
3.1 KiB
JavaScript

/**
* @module ol/interaction/KeyboardZoom
*/
import {inherits} from '../index.js';
import EventType from '../events/EventType.js';
import {targetNotEditable} from '../events/condition.js';
import Interaction, {zoomByDelta} from '../interaction/Interaction.js';
/**
* @typedef {Object} Options
* @property {number} [duration=100] Animation duration in milliseconds.
* @property {module:ol/events/condition~Condition} [condition] A function that
* takes an {@link module:ol/MapBrowserEvent~MapBrowserEvent} and returns a
* boolean to indicate whether that event should be handled. Default is
* {@link module:ol/events/condition~targetNotEditable}.
* @property {number} [delta=1] The zoom level delta on each key press.
*/
/**
* @classdesc
* Allows the user to zoom the map using keyboard + and -.
* Note that, although this interaction is by default included in maps,
* the keys can only be used when browser focus is on the element to which
* the keyboard events are attached. By default, this is the map div,
* though you can change this with the `keyboardEventTarget` in
* {@link module:ol/Map~Map}. `document` never loses focus but, for any other
* element, focus will have to be on, and returned to, this element if the keys
* are to function.
* See also {@link moudle:ol/interaction/KeyboardPan~KeyboardPan}.
*
* @constructor
* @param {module:ol/interaction/KeyboardZoom~Options=} opt_options Options.
* @extends {module:ol/interaction/Interaction~Interaction}
* @api
*/
const KeyboardZoom = function(opt_options) {
Interaction.call(this, {
handleEvent: handleEvent
});
const options = opt_options ? opt_options : {};
/**
* @private
* @type {module:ol/events/condition~Condition}
*/
this.condition_ = options.condition ? options.condition : targetNotEditable;
/**
* @private
* @type {number}
*/
this.delta_ = options.delta ? options.delta : 1;
/**
* @private
* @type {number}
*/
this.duration_ = options.duration !== undefined ? options.duration : 100;
};
inherits(KeyboardZoom, Interaction);
/**
* Handles the {@link module:ol/MapBrowserEvent~MapBrowserEvent map browser event} if it was a
* `KeyEvent`, and decides whether to zoom in or out (depending on whether the
* key pressed was '+' or '-').
* @param {module:ol/MapBrowserEvent~MapBrowserEvent} mapBrowserEvent Map browser event.
* @return {boolean} `false` to stop event propagation.
* @this {module:ol/interaction/KeyboardZoom~KeyboardZoom}
*/
function handleEvent(mapBrowserEvent) {
let stopEvent = false;
if (mapBrowserEvent.type == EventType.KEYDOWN ||
mapBrowserEvent.type == EventType.KEYPRESS) {
const keyEvent = mapBrowserEvent.originalEvent;
const charCode = keyEvent.charCode;
if (this.condition_(mapBrowserEvent) &&
(charCode == '+'.charCodeAt(0) || charCode == '-'.charCodeAt(0))) {
const map = mapBrowserEvent.map;
const delta = (charCode == '+'.charCodeAt(0)) ? this.delta_ : -this.delta_;
const view = map.getView();
zoomByDelta(view, delta, undefined, this.duration_);
mapBrowserEvent.preventDefault();
stopEvent = true;
}
}
return !stopEvent;
}
export default KeyboardZoom;