--- a/labs/openlayers/lib/OpenLayers/Control/NavigationHistory.js +++ b/labs/openlayers/lib/OpenLayers/Control/NavigationHistory.js @@ -1,1 +1,424 @@ - +/* 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" +}); + +