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61c528f3af33a92f72720902c18d8842183069ab
openlayers/lib/OpenLayers/Events.js
crschmidt 61c528f3af Change getMousePosition to only be called automatically *if* the 'includeXY' 
flag on the Events object is set to true. This ends up meaning that we save a
lot of unneccesary getMousePosition calls because (for example) the layer
doesn't need to include the .xy property. In addition, we add in speed
improvements via caching to the getMousePosition, courtesy the work from
pgiraud (which was worked on further by tcoulter) -- this results in
significantly improved getMousePosition performance improvements in 'real life'
situations that are more like the cases that people use OpenLayers, with a
higher number of containing divs (and also clearly demonstrate a gain in
performance even in the simple case.)

The end result is: 
 * In typical map movement over the map, (n / n+1) fewer calls to
   getMousePosition, where n is the number of active layers when dragging over
   the map.
 * In the simple case, 40% faster getMousePosition performance -- and in 
   more complex cases, significantly more performance improvements.

To drop the former improvement, which may affect some applications (as
described in the includeXY documentation) simply set:

  OpenLayers.Events.prototype.includeXY = true;

This will restore the 'every element has an xy property always' behavior
that was the case beore this patch. 

r=me,tschaub, work by pgiraud related to (See #1509), and (Closes #1459)


git-svn-id: http://svn.openlayers.org/trunk/openlayers@7615 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf
2008-07-30 21:23:19 +00:00

790 lines
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JavaScript
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/* Copyright (c) 2006-2008 MetaCarta, Inc., published under the Clear BSD
* license. See http://svn.openlayers.org/trunk/openlayers/license.txt for the
* full text of the license. */
/**
* @requires OpenLayers/Util.js
*/
/**
* Namespace: OpenLayers.Event
* Utility functions for event handling.
*/
OpenLayers.Event = {
/**
* Property: observers
* {Object} A hashtable cache of the event observers. Keyed by
* element._eventCacheID
*/
observers: false,
/**
* Constant: KEY_BACKSPACE
* {int}
*/
KEY_BACKSPACE: 8,
/**
* Constant: KEY_TAB
* {int}
*/
KEY_TAB: 9,
/**
* Constant: KEY_RETURN
* {int}
*/
KEY_RETURN: 13,
/**
* Constant: KEY_ESC
* {int}
*/
KEY_ESC: 27,
/**
* Constant: KEY_LEFT
* {int}
*/
KEY_LEFT: 37,
/**
* Constant: KEY_UP
* {int}
*/
KEY_UP: 38,
/**
* Constant: KEY_RIGHT
* {int}
*/
KEY_RIGHT: 39,
/**
* Constant: KEY_DOWN
* {int}
*/
KEY_DOWN: 40,
/**
* Constant: KEY_DELETE
* {int}
*/
KEY_DELETE: 46,
/**
* Method: element
* Cross browser event element detection.
*
* Parameters:
* event - {Event}
*
* Returns:
* {DOMElement} The element that caused the event
*/
element: function(event) {
return event.target || event.srcElement;
},
/**
* Method: isLeftClick
* Determine whether event was caused by a left click.
*
* Parameters:
* event - {Event}
*
* Returns:
* {Boolean}
*/
isLeftClick: function(event) {
return (((event.which) && (event.which == 1)) ||
((event.button) && (event.button == 1)));
},
/**
* Method: stop
* Stops an event from propagating.
*
* Parameters:
* event - {Event}
* allowDefault - {Boolean} If true, we stop the event chain but
* still allow the default browser
* behaviour (text selection, radio-button
* clicking, etc)
* Default false
*/
stop: function(event, allowDefault) {
if (!allowDefault) {
if (event.preventDefault) {
event.preventDefault();
} else {
event.returnValue = false;
}
}
if (event.stopPropagation) {
event.stopPropagation();
} else {
event.cancelBubble = true;
}
},
/**
* Method: findElement
*
* Parameters:
* event - {Event}
* tagName - {String}
*
* Returns:
* {DOMElement} The first node with the given tagName, starting from the
* node the event was triggered on and traversing the DOM upwards
*/
findElement: function(event, tagName) {
var element = OpenLayers.Event.element(event);
while (element.parentNode && (!element.tagName ||
(element.tagName.toUpperCase() != tagName.toUpperCase()))){
element = element.parentNode;
}
return element;
},
/**
* Method: observe
*
* Parameters:
* elementParam - {DOMElement || String}
* name - {String}
* observer - {function}
* useCapture - {Boolean}
*/
observe: function(elementParam, name, observer, useCapture) {
var element = OpenLayers.Util.getElement(elementParam);
useCapture = useCapture || false;
if (name == 'keypress' &&
(navigator.appVersion.match(/Konqueror|Safari|KHTML/)
|| element.attachEvent)) {
name = 'keydown';
}
//if observers cache has not yet been created, create it
if (!this.observers) {
this.observers = {};
}
//if not already assigned, make a new unique cache ID
if (!element._eventCacheID) {
var idPrefix = "eventCacheID_";
if (element.id) {
idPrefix = element.id + "_" + idPrefix;
}
element._eventCacheID = OpenLayers.Util.createUniqueID(idPrefix);
}
var cacheID = element._eventCacheID;
//if there is not yet a hash entry for this element, add one
if (!this.observers[cacheID]) {
this.observers[cacheID] = [];
}
//add a new observer to this element's list
this.observers[cacheID].push({
'element': element,
'name': name,
'observer': observer,
'useCapture': useCapture
});
//add the actual browser event listener
if (element.addEventListener) {
element.addEventListener(name, observer, useCapture);
} else if (element.attachEvent) {
element.attachEvent('on' + name, observer);
}
},
/**
* Method: stopObservingElement
* Given the id of an element to stop observing, cycle through the
* element's cached observers, calling stopObserving on each one,
* skipping those entries which can no longer be removed.
*
* parameters:
* elementParam - {DOMElement || String}
*/
stopObservingElement: function(elementParam) {
var element = OpenLayers.Util.getElement(elementParam);
var cacheID = element._eventCacheID;
this._removeElementObservers(OpenLayers.Event.observers[cacheID]);
},
/**
* Method: _removeElementObservers
*
* Parameters:
* elementObservers - {Array(Object)} Array of (element, name,
* observer, usecapture) objects,
* taken directly from hashtable
*/
_removeElementObservers: function(elementObservers) {
if (elementObservers) {
for(var i = elementObservers.length-1; i >= 0; i--) {
var entry = elementObservers[i];
var args = new Array(entry.element,
entry.name,
entry.observer,
entry.useCapture);
var removed = OpenLayers.Event.stopObserving.apply(this, args);
}
}
},
/**
* Method: stopObserving
*
* Parameters:
* elementParam - {DOMElement || String}
* name - {String}
* observer - {function}
* useCapture - {Boolean}
*
* Returns:
* {Boolean} Whether or not the event observer was removed
*/
stopObserving: function(elementParam, name, observer, useCapture) {
useCapture = useCapture || false;
var element = OpenLayers.Util.getElement(elementParam);
var cacheID = element._eventCacheID;
if (name == 'keypress') {
if ( navigator.appVersion.match(/Konqueror|Safari|KHTML/) ||
element.detachEvent) {
name = 'keydown';
}
}
// find element's entry in this.observers cache and remove it
var foundEntry = false;
var elementObservers = OpenLayers.Event.observers[cacheID];
if (elementObservers) {
// find the specific event type in the element's list
var i=0;
while(!foundEntry && i < elementObservers.length) {
var cacheEntry = elementObservers[i];
if ((cacheEntry.name == name) &&
(cacheEntry.observer == observer) &&
(cacheEntry.useCapture == useCapture)) {
elementObservers.splice(i, 1);
if (elementObservers.length == 0) {
delete OpenLayers.Event.observers[cacheID];
}
foundEntry = true;
break;
}
i++;
}
}
//actually remove the event listener from browser
if (foundEntry) {
if (element.removeEventListener) {
element.removeEventListener(name, observer, useCapture);
} else if (element && element.detachEvent) {
element.detachEvent('on' + name, observer);
}
}
return foundEntry;
},
/**
* Method: unloadCache
* Cycle through all the element entries in the events cache and call
* stopObservingElement on each.
*/
unloadCache: function() {
// check for OpenLayers.Event before checking for observers, because
// OpenLayers.Event may be undefined in IE if no map instance was
// created
if (OpenLayers.Event && OpenLayers.Event.observers) {
for (var cacheID in OpenLayers.Event.observers) {
var elementObservers = OpenLayers.Event.observers[cacheID];
OpenLayers.Event._removeElementObservers.apply(this,
[elementObservers]);
}
OpenLayers.Event.observers = false;
}
},
CLASS_NAME: "OpenLayers.Event"
};
/* prevent memory leaks in IE */
OpenLayers.Event.observe(window, 'unload', OpenLayers.Event.unloadCache, false);
// FIXME: Remove this in 3.0. In 3.0, Event.stop will no longer be provided
// by OpenLayers.
if (window.Event) {
OpenLayers.Util.applyDefaults(window.Event, OpenLayers.Event);
} else {
var Event = OpenLayers.Event;
}
/**
* Class: OpenLayers.Events
*/
OpenLayers.Events = OpenLayers.Class({
/**
* Constant: BROWSER_EVENTS
* {Array(String)} supported events
*/
BROWSER_EVENTS: [
"mouseover", "mouseout",
"mousedown", "mouseup", "mousemove",
"click", "dblclick",
"resize", "focus", "blur"
],
/**
* Property: listeners
* {Object} Hashtable of Array(Function): events listener functions
*/
listeners: null,
/**
* Property: object
* {Object} the code object issuing application events
*/
object: null,
/**
* Property: element
* {DOMElement} the DOM element receiving browser events
*/
element: null,
/**
* Property: eventTypes
* {Array(String)} list of support application events
*/
eventTypes: null,
/**
* Property: eventHandler
* {Function} bound event handler attached to elements
*/
eventHandler: null,
/**
* APIProperty: fallThrough
* {Boolean}
*/
fallThrough: null,
/**
* APIProperty: includeXY
* {Boolean} Should the .xy property automatically be created for browser
* mouse events? In general, this should be false. If it is true, then
* mouse events will automatically generate a '.xy' property on the
* event object that is passed. (Prior to OpenLayers 2.7, this was true
* by default.) Otherwise, you can call the getMousePosition on the
* relevant events handler on the object available via the 'evt.object'
* property of the evt object. So, for most events, you can call:
* function named(evt) {
* this.xy = this.object.events.getMousePosition(evt)
* }
*
* This option typically defaults to false for performance reasons:
* when creating an events object whose primary purpose is to manage
* relatively positioned mouse events within a div, it may make
* sense to set it to true.
*
* This option is also used to control whether the events object caches
* offsets. If this is false, it will not: the reason for this is that
* it is only expected to be called many times if the includeXY property
* is set to true. If you set this to true, you are expected to clear
* the offset cache manually (using this.clearMouseCache()) if:
* the border of the element changes
* the location of the element in the page changes
*/
includeXY: false,
/**
* Constructor: OpenLayers.Events
* Construct an OpenLayers.Events object.
*
* Parameters:
* object - {Object} The js object to which this Events object is being
* added element - {DOMElement} A dom element to respond to browser events
* eventTypes - {Array(String)} Array of custom application events
* fallThrough - {Boolean} Allow events to fall through after these have
* been handled?
* options - {Object} Options for the events object.
*/
initialize: function (object, element, eventTypes, fallThrough, options) {
OpenLayers.Util.extend(this, options);
this.object = object;
this.element = element;
this.fallThrough = fallThrough;
this.listeners = {};
// keep a bound copy of handleBrowserEvent() so that we can
// pass the same function to both Event.observe() and .stopObserving()
this.eventHandler = OpenLayers.Function.bindAsEventListener(
this.handleBrowserEvent, this
);
// if eventTypes is specified, create a listeners list for each
// custom application event.
this.eventTypes = [];
if (eventTypes != null) {
for (var i = 0; i < eventTypes.length; i++) {
this.addEventType(eventTypes[i]);
}
}
// if a dom element is specified, add a listeners list
// for browser events on the element and register them
if (this.element != null) {
this.attachToElement(element);
}
},
/**
* APIMethod: destroy
*/
destroy: function () {
if (this.element) {
OpenLayers.Event.stopObservingElement(this.element);
}
this.element = null;
this.listeners = null;
this.object = null;
this.eventTypes = null;
this.fallThrough = null;
this.eventHandler = null;
},
/**
* APIMethod: addEventType
* Add a new event type to this events object.
* If the event type has already been added, do nothing.
*
* Parameters:
* eventName - {String}
*/
addEventType: function(eventName) {
if (!this.listeners[eventName]) {
this.eventTypes.push(eventName);
this.listeners[eventName] = [];
}
},
/**
* Method: attachToElement
*
* Parameters:
* element - {HTMLDOMElement} a DOM element to attach browser events to
*/
attachToElement: function (element) {
for (var i = 0; i < this.BROWSER_EVENTS.length; i++) {
var eventType = this.BROWSER_EVENTS[i];
// every browser event has a corresponding application event
// (whether it's listened for or not).
this.addEventType(eventType);
// use Prototype to register the event cross-browser
OpenLayers.Event.observe(element, eventType, this.eventHandler);
}
// disable dragstart in IE so that mousedown/move/up works normally
OpenLayers.Event.observe(element, "dragstart", OpenLayers.Event.stop);
},
/**
* Method: on
* Convenience method for registering listeners with a common scope.
*
* Example use:
* (code)
* events.on({
* "loadstart": loadStartListener,
* "loadend": loadEndListener,
* scope: object
* });
* (end)
*/
on: function(object) {
for(var type in object) {
if(type != "scope") {
this.register(type, object.scope, object[type]);
}
}
},
/**
* APIMethod: register
* Register an event on the events object.
*
* When the event is triggered, the 'func' function will be called, in the
* context of 'obj'. Imagine we were to register an event, specifying an
* OpenLayers.Bounds Object as 'obj'. When the event is triggered, the
* context in the callback function will be our Bounds object. This means
* that within our callback function, we can access the properties and
* methods of the Bounds object through the "this" variable. So our
* callback could execute something like:
* : leftStr = "Left: " + this.left;
*
* or
*
* : centerStr = "Center: " + this.getCenterLonLat();
*
* Parameters:
* type - {String} Name of the event to register
* obj - {Object} The object to bind the context to for the callback#.
* If no object is specified, default is the Events's
* 'object' property.
* func - {Function} The callback function. If no callback is
* specified, this function does nothing.
*
*
*/
register: function (type, obj, func) {
if ( (func != null) &&
(OpenLayers.Util.indexOf(this.eventTypes, type) != -1) ) {
if (obj == null) {
obj = this.object;
}
var listeners = this.listeners[type];
listeners.push( {obj: obj, func: func} );
}
},
/**
* APIMethod: registerPriority
* Same as register() but adds the new listener to the *front* of the
* events queue instead of to the end.
*
* TODO: get rid of this in 3.0 - Decide whether listeners should be
* called in the order they were registered or in reverse order.
*
*
* Parameters:
* type - {String} Name of the event to register
* obj - {Object} The object to bind the context to for the callback#.
* If no object is specified, default is the Events's
* 'object' property.
* func - {Function} The callback function. If no callback is
* specified, this function does nothing.
*/
registerPriority: function (type, obj, func) {
if (func != null) {
if (obj == null) {
obj = this.object;
}
var listeners = this.listeners[type];
if (listeners != null) {
listeners.unshift( {obj: obj, func: func} );
}
}
},
/**
* Method: un
* Convenience method for unregistering listeners with a common scope.
*
* Example use:
* (code)
* events.un({
* "loadstart": loadStartListener,
* "loadend": loadEndListener,
* scope: object
* });
* (end)
*/
un: function(object) {
for(var type in object) {
if(type != "scope") {
this.unregister(type, object.scope, object[type]);
}
}
},
/**
* APIMethod: unregister
*
* Parameters:
* type - {String}
* obj - {Object} If none specified, defaults to this.object
* func - {Function}
*/
unregister: function (type, obj, func) {
if (obj == null) {
obj = this.object;
}
var listeners = this.listeners[type];
if (listeners != null) {
for (var i = 0; i < listeners.length; i++) {
if (listeners[i].obj == obj && listeners[i].func == func) {
listeners.splice(i, 1);
break;
}
}
}
},
/**
* Method: remove
* Remove all listeners for a given event type. If type is not registered,
* does nothing.
*
* Parameters:
* type - {String}
*/
remove: function(type) {
if (this.listeners[type] != null) {
this.listeners[type] = [];
}
},
/**
* APIMethod: triggerEvent
* Trigger a specified registered event.
*
* Parameters:
* type - {String}
* evt - {Event}
*
* Returns:
* {Boolean} The last listener return. If a listener returns false, the
* chain of listeners will stop getting called.
*/
triggerEvent: function (type, evt) {
// prep evt object with object & div references
if (evt == null) {
evt = {};
}
evt.object = this.object;
evt.element = this.element;
if(!evt.type) {
evt.type = type;
}
// execute all callbacks registered for specified type
// get a clone of the listeners array to
// allow for splicing during callbacks
var listeners = (this.listeners[type]) ?
this.listeners[type].slice() : null;
if ((listeners != null) && (listeners.length > 0)) {
var continueChain;
for (var i = 0; i < listeners.length; i++) {
var callback = listeners[i];
// bind the context to callback.obj
continueChain = callback.func.apply(callback.obj, [evt]);
if ((continueChain != undefined) && (continueChain == false)) {
// if callback returns false, execute no more callbacks.
break;
}
}
// don't fall through to other DOM elements
if (!this.fallThrough) {
OpenLayers.Event.stop(evt, true);
}
}
return continueChain;
},
/**
* Method: handleBrowserEvent
* Basically just a wrapper to the triggerEvent() function, but takes
* care to set a property 'xy' on the event with the current mouse
* position.
*
* Parameters:
* evt - {Event}
*/
handleBrowserEvent: function (evt) {
if (this.includeXY) {
evt.xy = this.getMousePosition(evt);
}
this.triggerEvent(evt.type, evt);
},
/**
* APIMethod: clearMouseCache
* Clear cached data about the mouse position. This should be called any
* time the element that events are registered on changes position
* within the page.
*/
clearMouseCache: function() {
this.element.scrolls = null;
this.element.lefttop = null;
this.element.offsets = null;
},
/**
* Method: getMousePosition
*
* Parameters:
* evt - {Event}
*
* Returns:
* {<OpenLayers.Pixel>} The current xy coordinate of the mouse, adjusted
* for offsets
*/
getMousePosition: function (evt) {
if (!this.includeXY) {
this.clearMouseCache();
} else if (!this.element.hasScrollEvent) {
OpenLayers.Event.observe(window, 'scroll',
OpenLayers.Function.bind(this.clearMouseCache, this));
this.element.hasScrollEvent = true;
}
if (!this.element.scrolls) {
this.element.scrolls = [];
this.element.scrolls[0] = (document.documentElement.scrollLeft
|| document.body.scrollLeft);
this.element.scrolls[1] = (document.documentElement.scrollTop
|| document.body.scrollTop);
}
if (!this.element.lefttop) {
this.element.lefttop = [];
this.element.lefttop[0] = (document.documentElement.clientLeft || 0);
this.element.lefttop[1] = (document.documentElement.clientTop || 0);
}
if (!this.element.offsets) {
this.element.offsets = OpenLayers.Util.pagePosition(this.element);
this.element.offsets[0] += this.element.scrolls[0];
this.element.offsets[1] += this.element.scrolls[1];
}
return new OpenLayers.Pixel(
(evt.clientX + this.element.scrolls[0]) - this.element.offsets[0]
- this.element.lefttop[0],
(evt.clientY + this.element.scrolls[1]) - this.element.offsets[1]
- this.element.lefttop[1]
);
},
CLASS_NAME: "OpenLayers.Events"
});
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