Files
openlayers/src/ol/event/Drag.js
ahocevar e67e9049ca preventDefault and stopPropagation convenience functions.
These functions can directly be used as browser event listeners.
2012-07-08 12:12:19 +02:00

95 lines
3.1 KiB
JavaScript

goog.provide('ol.event.Drag');
goog.require('ol.event');
goog.require('ol.event.ISequence');
goog.require('goog.functions');
goog.require('goog.fx.Dragger');
goog.require('goog.fx.DragEvent');
goog.require('goog.fx.Dragger.EventType');
/**
* Event sequence that provides a 'dragstart', 'drag' and 'dragend' events.
* Event objects of the 'drag' events have 'deltaX' and 'deltaY' values with
* the relative pixel movement since the previous 'drag' or 'dragstart' event.
*
* @constructor
* @param {ol.event.Events} target The Events instance that handles events.
* @implements {ol.event.ISequence}
* @export
*/
ol.event.Drag = function(target) {
var previousX = 0, previousY = 0,
element = target.getElement(),
dragger = new goog.fx.Dragger(element);
/**
* @private
* @type {goog.fx.Dragger}
*/
this.dragger_ = dragger;
/**
* @private
* @type {ol.event.Events}
*/
this.target_ = target;
// We want to swallow the click event that gets fired after dragging.
var newSequence;
function unregisterClickStopper() {
target.unregister('click', goog.functions.FALSE, undefined, true);
}
// no default for mousemove and touchmove events to avoid page scrolling.
target.register('mousemove', ol.event.preventDefault);
target.register('touchmove', ol.event.preventDefault);
dragger.defaultAction = function(x, y) {};
dragger.addEventListener(goog.fx.Dragger.EventType.START, function(evt) {
evt.target = element;
evt.type = 'dragstart';
previousX = evt.clientX;
previousY = evt.clientY;
newSequence = true;
target.triggerEvent(evt.type, evt);
});
dragger.addEventListener(goog.fx.Dragger.EventType.DRAG, function(evt) {
evt.target = element;
evt.deltaX = evt.clientX - previousX;
evt.deltaY = evt.clientY - previousY;
previousX = evt.clientX;
previousY = evt.clientY;
if (newSequence) {
// Once we are in the drag sequence, we know that we need to
// get rid of the click event that gets fired when we are done
// dragging.
target.register('click', goog.functions.FALSE, undefined, true);
newSequence = false;
}
target.triggerEvent(evt.type, evt);
});
dragger.addEventListener(goog.fx.Dragger.EventType.END, function(evt) {
evt.target = element;
evt.type = 'dragend';
target.triggerEvent(evt.type, evt);
// Unregister the click stopper in the next cycle
window.setTimeout(unregisterClickStopper, 0);
});
// Don't swallow the click event if our sequence cancels early.
dragger.addEventListener(
goog.fx.Dragger.EventType.EARLY_CANCEL, unregisterClickStopper
);
};
/** @inheritDoc */
ol.event.Drag.prototype.destroy = function() {
this.target_.unregister('mousemove', ol.event.preventDefault);
this.target_.unregister('touchmove', ol.event.preventDefault);
this.dragger_.dispose();
goog.object.clear(this);
};
ol.event.addSequenceProvider('drag', ol.event.Drag);