/* Copyright (c) 2006-2010 by OpenLayers Contributors (see authors.txt for
* full list of contributors). Published under the Clear BSD license.
* See http://svn.openlayers.org/trunk/openlayers/license.txt for the
* full text of the license. */
/**
* @requires OpenLayers/Control.js
* @requires OpenLayers/Control/Button.js
*/
/**
* Class: OpenLayers.Control.NavigationHistory
* A navigation history control. This is a meta-control, that creates two
* dependent controls: <previous> and <next>. Call the trigger method
* on the <previous> and <next> controls to restore previous and next
* history states. The previous and next controls will become active
* when there are available states to restore and will become deactive
* when there are no states to restore.
*
* Inherits from:
* - <OpenLayers.Control>
*/
OpenLayers.Control.NavigationHistory = OpenLayers.Class(OpenLayers.Control, {
/**
* Property: type
* {String} Note that this control is not intended to be added directly
* to a control panel. Instead, add the sub-controls previous and
* next. These sub-controls are button type controls that activate
* and deactivate themselves. If this parent control is added to
* a panel, it will act as a toggle.
*/
type: OpenLayers.Control.TYPE_TOGGLE,
/**
* APIProperty: previous
* {<OpenLayers.Control>} A button type control whose trigger method restores
* the previous state managed by this control.
*/
previous: null,
/**
* APIProperty: previousOptions
* {Object} Set this property on the options argument of the constructor
* to set optional properties on the <previous> control.
*/
previousOptions: null,
/**
* APIProperty: next
* {<OpenLayers.Control>} A button type control whose trigger method restores
* the next state managed by this control.
*/
next: null,
/**
* APIProperty: nextOptions
* {Object} Set this property on the options argument of the constructor
* to set optional properties on the <next> control.
*/
nextOptions: null,
/**
* APIProperty: limit
* {Integer} Optional limit on the number of history items to retain. If
* null, there is no limit. Default is 50.
*/
limit: 50,
/**
* APIProperty: autoActivate
* {Boolean} Activate the control when it is added to a map. Default is
* true.
*/
autoActivate: true,
/**
* Property: clearOnDeactivate
* {Boolean} Clear the history when the control is deactivated. Default
* is false.
*/
clearOnDeactivate: false,
/**
* Property: registry
* {Object} An object with keys corresponding to event types. Values
* are functions that return an object representing the current state.
*/
registry: null,
/**
* Property: nextStack
* {Array} Array of items in the history.
*/
nextStack: null,
/**
* Property: previousStack
* {Array} List of items in the history. First item represents the current
* state.
*/
previousStack: null,
/**
* Property: listeners
* {Object} An object containing properties corresponding to event types.
* This object is used to configure the control and is modified on
* construction.
*/
listeners: null,
/**
* Property: restoring
* {Boolean} Currently restoring a history state. This is set to true
* before calling restore and set to false after restore returns.
*/
restoring: false,
/**
* Constructor: OpenLayers.Control.NavigationHistory
*
* Parameters:
* options - {Object} An optional object whose properties will be used
* to extend the control.
*/
initialize: function(options) {
OpenLayers.Control.prototype.initialize.apply(this, [options]);
this.registry = OpenLayers.Util.extend({
"moveend": this.getState
}, this.registry);
var previousOptions = {
trigger: OpenLayers.Function.bind(this.previousTrigger, this),
displayClass: this.displayClass + " " + this.displayClass + "Previous"
};
OpenLayers.Util.extend(previousOptions, this.previousOptions);
this.previous = new OpenLayers.Control.Button(previousOptions);
var nextOptions = {
trigger: OpenLayers.Function.bind(this.nextTrigger, this),
displayClass: this.displayClass + " " + this.displayClass + "Next"
};
OpenLayers.Util.extend(nextOptions, this.nextOptions);
this.next = new OpenLayers.Control.Button(nextOptions);
this.clear();
},
/**
* Method: onPreviousChange
* Called when the previous history stack changes.
*
* Parameters:
* state - {Object} An object representing the state to be restored
* if previous is triggered again or null if no previous states remain.
* length - {Integer} The number of remaining previous states that can
* be restored.
*/
onPreviousChange: function(state, length) {
if(state && !this.previous.active) {
this.previous.activate();
} else if(!state && this.previous.active) {
this.previous.deactivate();
}
},
/**
* Method: onNextChange
* Called when the next history stack changes.
*
* Parameters:
* state - {Object} An object representing the state to be restored
* if next is triggered again or null if no next states remain.
* length - {Integer} The number of remaining next states that can
* be restored.
*/
onNextChange: function(state, length) {
if(state && !this.next.active) {
this.next.activate();
} else if(!state && this.next.active) {
this.next.deactivate();
}
},
/**
* APIMethod: destroy
* Destroy the control.
*/
destroy: function() {
OpenLayers.Control.prototype.destroy.apply(this);
this.previous.destroy();
this.next.destroy();
this.deactivate();
for(var prop in this) {
this[prop] = null;
}
},
/**
* Method: setMap
* Set the map property for the control and <previous> and <next> child
* controls.
*
* Parameters:
* map - {<OpenLayers.Map>}
*/
setMap: function(map) {
this.map = map;
this.next.setMap(map);
this.previous.setMap(map);
},
/**
* Method: draw
* Called when the control is added to the map.
*/
draw: function() {
OpenLayers.Control.prototype.draw.apply(this, arguments);
this.next.draw();
this.previous.draw();
},
/**
* Method: previousTrigger
* Restore the previous state. If no items are in the previous history
* stack, this has no effect.
*
* Returns:
* {Object} Item representing state that was restored. Undefined if no
* items are in the previous history stack.
*/
previousTrigger: function() {
var current = this.previousStack.shift();
var state = this.previousStack.shift();
if(state != undefined) {
this.nextStack.unshift(current);
this.previousStack.unshift(state);
this.restoring = true;
this.restore(state);
this.restoring = false;
this.onNextChange(this.nextStack[0], this.nextStack.length);
this.onPreviousChange(
this.previousStack[1], this.previousStack.length - 1
);
} else {
this.previousStack.unshift(current);
}
return state;
},
/**
* APIMethod: nextTrigger
* Restore the next state. If no items are in the next history
* stack, this has no effect. The next history stack is populated
* as states are restored from the previous history stack.
*
* Returns:
* {Object} Item representing state that was restored. Undefined if no
* items are in the next history stack.
*/
nextTrigger: function() {
var state = this.nextStack.shift();
if(state != undefined) {
this.previousStack.unshift(state);
this.restoring = true;
this.restore(state);
this.restoring = false;
this.onNextChange(this.nextStack[0], this.nextStack.length);
this.onPreviousChange(
this.previousStack[1], this.previousStack.length - 1
);
}
return state;
},
/**
* APIMethod: clear
* Clear history.
*/
clear: function() {
this.previousStack = [];
this.previous.deactivate();
this.nextStack = [];
this.next.deactivate();
},
/**
* Method: getState
* Get the current state and return it.
*
* Returns:
* {Object} An object representing the current state.
*/
getState: function() {
return {
center: this.map.getCenter(),
resolution: this.map.getResolution(),
projection: this.map.getProjectionObject(),
units: this.map.getProjectionObject().getUnits() ||
this.map.units || this.map.baseLayer.units
};
},
/**
* Method: restore
* Update the state with the given object.
*
* Parameters:
* state - {Object} An object representing the state to restore.
*/
restore: function(state) {
var center, zoom;
if (this.map.getProjectionObject() == state.projection) {
zoom = this.map.getZoomForResolution(state.resolution);
center = state.center;
} else {
center = state.center.clone();
center.transform(state.projection, this.map.getProjectionObject());
var sourceUnits = state.units;
var targetUnits = this.map.getProjectionObject().getUnits() ||
this.map.units || this.map.baseLayer.units;
var resolutionFactor = sourceUnits && targetUnits ?
OpenLayers.INCHES_PER_UNIT[sourceUnits] / OpenLayers.INCHES_PER_UNIT[targetUnits] : 1;
zoom = this.map.getZoomForResolution(resolutionFactor*state.resolution);
}
this.map.setCenter(center, zoom);
},
/**
* Method: setListeners
* Sets functions to be registered in the listeners object.
*/
setListeners: function() {
this.listeners = {};
for(var type in this.registry) {
this.listeners[type] = OpenLayers.Function.bind(function() {
if(!this.restoring) {
var state = this.registry[type].apply(this, arguments);
this.previousStack.unshift(state);
if(this.previousStack.length > 1) {
this.onPreviousChange(
this.previousStack[1], this.previousStack.length - 1
);
}
if(this.previousStack.length > (this.limit + 1)) {
this.previousStack.pop();
}
if(this.nextStack.length > 0) {
this.nextStack = [];
this.onNextChange(null, 0);
}
}
return true;
}, this);
}
},
/**
* APIMethod: activate
* Activate the control. This registers any listeners.
*
* Returns:
* {Boolean} Control successfully activated.
*/
activate: function() {
var activated = false;
if(this.map) {
if(OpenLayers.Control.prototype.activate.apply(this)) {
if(this.listeners == null) {
this.setListeners();
}
for(var type in this.listeners) {
this.map.events.register(type, this, this.listeners[type]);
}
activated = true;
if(this.previousStack.length == 0) {
this.initStack();
}
}
}
return activated;
},
/**
* Method: initStack
* Called after the control is activated if the previous history stack is
* empty.
*/
initStack: function() {
if(this.map.getCenter()) {
this.listeners.moveend();
}
},
/**
* APIMethod: deactivate
* Deactivate the control. This unregisters any listeners.
*
* Returns:
* {Boolean} Control successfully deactivated.
*/
deactivate: function() {
var deactivated = false;
if(this.map) {
if(OpenLayers.Control.prototype.deactivate.apply(this)) {
for(var type in this.listeners) {
this.map.events.unregister(
type, this, this.listeners[type]
);
}
if(this.clearOnDeactivate) {
this.clear();
}
deactivated = true;
}
}
return deactivated;
},
CLASS_NAME: "OpenLayers.Control.NavigationHistory"
});