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3948913bfc6fec56c6cb8deda589bc64ce344949
openlayers/lib/OpenLayers/Events.js
crschmidt 3948913bfc Merge all changes from the naturaldocs sandbox. This brings all the work that 
has been done in the NaturalDocs branch back to trunk. Thanks to everyone who
helped out in making this happen. (I could list people, but the list would
be long, and I'm already mentally on vacation.)


git-svn-id: http://svn.openlayers.org/trunk/openlayers@3545 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf
2007-06-29 15:59:20 +00:00

661 lines
19 KiB
JavaScript
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/* Copyright (c) 2006 MetaCarta, Inc., published under a modified BSD license.
* See http://svn.openlayers.org/trunk/openlayers/repository-license.txt
* for the full text of the license. */
/**
* @requires OpenLayers/Util.js
*
* Title: OpenLayers.Events
*
* Class: 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}
*
* Return:
* {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 = new Object();
}
//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] = new Array();
}
//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
* *Private*.
*
* 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}
*
* Return:
* {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 (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() {
if (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;
}
},
/** @final @type String */
CLASS_NAME: "OpenLayers.Event"
};
/* prevent memory leaks in IE */
OpenLayers.Event.observe(window, 'unload', OpenLayers.Event.unloadCache, false);
if (window.Event) {
OpenLayers.Util.extend(window.Event, OpenLayers.Event);
} else {
var Event = OpenLayers.Event;
}
/**
* Class: OpenLayers.Events
*/
OpenLayers.Events = OpenLayers.Class.create();
OpenLayers.Events.prototype = {
/**
* Constant: BROWSER_EVENTS
* {Array} 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} list of support application events
*/
eventTypes: null,
/**
* Property: eventHandler
* {Function} bound event handler attached to elements
*/
eventHandler: null,
/**
* Property: fallThrough
* {Boolean}
*/
fallThrough: null,
/**
* 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} Array of custom application events
* fallThrough - {Boolean} Allow events to fall through after these have
* been handled?
*/
initialize: function (object, element, eventTypes, fallThrough) {
this.object = object;
this.element = element;
this.eventTypes = eventTypes;
this.fallThrough = fallThrough;
this.listeners = new Object();
// keep a bound copy of handleBrowserEvent() so that we can
// pass the same function to both Event.observe() and .stopObserving()
this.eventHandler = this.handleBrowserEvent.bindAsEventListener(this);
// if eventTypes is specified, create a listeners list for each
// custom application event.
if (this.eventTypes != null) {
for (var i = 0; i < this.eventTypes.length; i++) {
this.listeners[ this.eventTypes[i] ] = new Array();
}
}
// 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);
}
},
/**
* Method: 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;
},
/**
* 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).
if (this.listeners[eventType] == null) {
this.listeners[eventType] = new Array();
}
// 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: 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) {
if (obj == null) {
obj = this.object;
}
var listeners = this.listeners[type];
if (listeners != null) {
listeners.push( {obj: obj, func: func} );
}
}
},
/**
* TODO: get rid of this in 3.0 - Decide whether listeners should be
* called in the order they were registered or in reverse order.
*
* Method: registerPriority
*
* 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: 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] = new Array();
}
},
/**
* Method: triggerEvent
* Trigger a specified registered event
*
* Parameters:
* type - {String}
* evt - {Event}
*/
triggerEvent: function (type, evt) {
// prep evt object with object & div references
if (evt == null) {
evt = new Object();
}
evt.object = this.object;
evt.element = this.element;
// 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)) {
for (var i = 0; i < listeners.length; i++) {
var callback = listeners[i];
var continueChain;
if (callback.obj != null) {
// use the 'call' method to bind the context to callback.obj
continueChain = callback.func.call(callback.obj, evt);
} else {
continueChain = callback.func(evt);
}
if ((continueChain != null) && (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);
}
}
},
/**
* 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.
*
* Private function.
*
* Parameters:
* evt - {Event}
*/
handleBrowserEvent: function (evt) {
evt.xy = this.getMousePosition(evt);
this.triggerEvent(evt.type, evt)
},
/**
* Method: getMousePosition
* *Private*
*
* Parameters:
* evt - {Event}
*
* Returns
* {<OpenLayers.Pixel>} The current xy coordinate of the mouse, adjusted
* for offsets
*/
getMousePosition: function (evt) {
if (!this.element.offsets) {
this.element.offsets = OpenLayers.Util.pagePosition(this.element);
this.element.offsets[0] += (document.documentElement.scrollLeft
|| document.body.scrollLeft);
this.element.offsets[1] += (document.documentElement.scrollTop
|| document.body.scrollTop);
}
return new OpenLayers.Pixel(
(evt.clientX + (document.documentElement.scrollLeft
|| document.body.scrollLeft)) - this.element.offsets[0],
(evt.clientY + (document.documentElement.scrollTop
|| document.body.scrollTop)) - this.element.offsets[1]
);
},
/** @final @type String */
CLASS_NAME: "OpenLayers.Events"
};
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