42c4c9d869
If MapHandler subclasses could live without a map, it would make sense to have a constructor with a target and an element. But because the target is always the map, and the handler need to know about the map for performing default behavior, we always assume the map's viewport as element.
75 lines
2.1 KiB
JavaScript
75 lines
2.1 KiB
JavaScript
/**
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* @fileoverview Mouse Wheel Handler.
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*
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* Provides a class for listening to mousewheel events on a DOM element
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* and dispatching mousewheel events to a map instance.
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*
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* The default behavior for the mousewheel event is zooming the map.
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*/
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goog.provide('ol.handler.MouseWheel');
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goog.require('ol.handler.MapHandler');
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goog.require('ol.events.MapEvent');
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goog.require('ol.events.MapEventType');
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goog.require('goog.asserts');
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goog.require('goog.events');
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goog.require('goog.style');
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goog.require('goog.events.MouseWheelHandler');
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goog.require('goog.events.MouseWheelHandler.EventType');
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/**
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* @constructor
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* @extends {ol.handler.MapHandler}
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* @param {ol.Map} map The map instance.
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* @param {ol.handler.states} states An object for the handlers to share
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* states.
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*/
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ol.handler.MouseWheel = function(map, states) {
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goog.base(this, map, states);
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var handler = new goog.events.MouseWheelHandler(this.element_);
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this.registerDisposable(handler);
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goog.events.listen(handler,
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goog.events.MouseWheelHandler.EventType.MOUSEWHEEL,
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this.handleMouseWheel, false, this);
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};
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goog.inherits(ol.handler.MouseWheel, ol.handler.MapHandler);
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/**
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* @param {goog.events.MouseWheelEvent} e
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*/
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ol.handler.MouseWheel.prototype.handleMouseWheel = function(e) {
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var newE = new ol.events.MapEvent(ol.events.MapEventType.MOUSEWHEEL, e);
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var rt = goog.events.dispatchEvent(this.map_, newE);
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if (rt) {
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this.defaultMouseWheel(e);
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}
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};
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/**
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* @param {goog.events.MouseWheelEvent} e
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*/
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ol.handler.MouseWheel.prototype.defaultMouseWheel = function(e) {
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var me = this;
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if (e.deltaY === 0 || me.zoomBlocked_) {
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return;
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}
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me.zoomBlocked_ = window.setTimeout(function() {
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me.zoomBlocked_ = null;
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}, 200);
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var map = me.map_,
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step = e.deltaY / Math.abs(e.deltaY);
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map.setZoom(map.getZoom() - step,
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goog.style.getRelativePosition(e, this.element_));
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// We don't want the page to scroll.
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// (MouseWheelEvent is a BrowserEvent)
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e.preventDefault();
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};
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