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/* Copyright (c) 2006-2013 by OpenLayers Contributors (see authors.txt for
* full list of contributors). Published under the 2-clause BSD license.
* See license.txt in the OpenLayers distribution or repository for the
* full text of the license. */
/**
* @requires OpenLayers/Control.js
* @requires OpenLayers/Handler/Hover.js
* @requires OpenLayers/Handler/Click.js
*/
/**
* Class: OpenLayers.Control.UTFGrid
*
* This Control provides behavior associated with UTFGrid Layers.
* These 'hit grids' provide underlying feature attributes without
* calling the server (again). This control allows Mousemove, Hovering
* and Click events to trigger callbacks that use the attributes in
* whatever way you need.
*
* The most common example may be a UTFGrid layer containing feature
* attributes that are displayed in a div as you mouseover.
*
* Example Code:
*
* (start code)
* var world_utfgrid = new OpenLayers.Layer.UTFGrid(
* 'UTFGrid Layer',
* "http://tiles/world_utfgrid/${z}/${x}/${y}.json"
* );
* map.addLayer(world_utfgrid);
*
* var control = new OpenLayers.Control.UTFGrid({
* layers: [world_utfgrid],
* handlerMode: 'move',
* callback: function(infoLookup) {
* // do something with returned data
*
* }
* })
* (end code)
*
*
* Inherits from:
* - <OpenLayers.Control>
*/
OpenLayers.Control.UTFGrid = OpenLayers.Class(OpenLayers.Control, {
/**
* APIProperty: autoActivate
* {Boolean} Activate the control when it is added to a map. Default is
* true.
*/
autoActivate: true,
/**
* APIProperty: Layers
* List of layers to consider. Must be Layer.UTFGrids
* `null` is the default indicating all UTFGrid Layers are queried.
* {Array} <OpenLayers.Layer.UTFGrid>
*/
layers: null,
/* Property: defaultHandlerOptions
* The default opts passed to the handler constructors
*/
defaultHandlerOptions: {
'delay': 300,
'pixelTolerance': 4,
'stopMove': false,
'single': true,
'double': false,
'stopSingle': false,
'stopDouble': false
},
/* APIProperty: handlerMode
* Defaults to 'click'. Can be 'hover' or 'move'.
*/
handlerMode: 'click',
/**
* APIMethod: setHandler
* sets this.handlerMode and calls resetHandler()
*
* Parameters:
* hm - {String} Handler Mode string; 'click', 'hover' or 'move'.
*/
setHandler: function(hm) {
this.handlerMode = hm;
this.resetHandler();
},
/**
* Method: resetHandler
* Deactivates the old hanlder and creates a new
* <OpenLayers.Handler> based on the mode specified in
* this.handlerMode
*
*/
resetHandler: function() {
if (this.handler) {
this.handler.deactivate();
this.handler.destroy();
this.handler = null;
}
if (this.handlerMode == 'hover') {
// Handle this event on hover
this.handler = new OpenLayers.Handler.Hover(
this,
{'pause': this.handleEvent, 'move': this.reset},
this.handlerOptions
);
} else if (this.handlerMode == 'click') {
// Handle this event on click
this.handler = new OpenLayers.Handler.Click(
this, {
'click': this.handleEvent
}, this.handlerOptions
);
} else if (this.handlerMode == 'move') {
this.handler = new OpenLayers.Handler.Hover(
this,
// Handle this event while hovering OR moving
{'pause': this.handleEvent, 'move': this.handleEvent},
this.handlerOptions
);
}
if (this.handler) {
return true;
} else {
return false;
}
},
/**
* Constructor: <OpenLayers.Control.UTFGrid>
*
* Parameters:
* options - {Object}
*/
initialize: function(options) {
options = options || {};
options.handlerOptions = options.handlerOptions || this.defaultHandlerOptions;
OpenLayers.Control.prototype.initialize.apply(this, [options]);
this.resetHandler();
},
/**
* Method: handleEvent
* Internal method called when specified event is triggered.
*
* This method does several things:
*
* Gets the lonLat of the event.
*
* Loops through the appropriate hit grid layers and gathers the attributes.
*
* Passes the attributes to the callback
*
* Parameters:
* evt - {<OpenLayers.Event>}
*/
handleEvent: function(evt) {
if (evt == null) {
this.reset();
return;
}
var lonLat = this.map.getLonLatFromPixel(evt.xy);
if (!lonLat) {
return;
}
var layers = this.findLayers();
if (layers.length > 0) {
var infoLookup = {};
var layer, idx;
for (var i=0, len=layers.length; i<len; i++) {
layer = layers[i];
idx = OpenLayers.Util.indexOf(this.map.layers, layer);
infoLookup[idx] = layer.getFeatureInfo(lonLat);
}
this.callback(infoLookup, lonLat, evt.xy);
}
},
/**
* APIMethod: callback
* Function to be called when a mouse event corresponds with a location that
* includes data in one of the configured UTFGrid layers.
*
* Parameters:
* infoLookup - {Object} Keys of this object are layer indexes and can be
* used to resolve a layer in the map.layers array. The structure of
* the property values depend on the data included in the underlying
* UTFGrid and may be any valid JSON type.
*/
callback: function(infoLookup) {
// to be provided in the constructor
},
/**
* Method: reset
* Calls the callback with null.
*/
reset: function(evt) {
this.callback(null);
},
/**
* Method: findLayers
* Internal method to get the layers, independent of whether we are
* inspecting the map or using a client-provided array
*
* The default value of this.layers is null; this causes the
* findLayers method to return ALL UTFGrid layers encountered.
*
* Parameters:
* None
*
* Returns:
* {Array} Layers to handle on each event
*/
findLayers: function() {
var candidates = this.layers || this.map.layers;
var layers = [];
var layer;
for (var i=candidates.length-1; i>=0; --i) {
layer = candidates[i];
if (layer instanceof OpenLayers.Layer.UTFGrid ) {
layers.push(layer);
}
}
return layers;
},
CLASS_NAME: "OpenLayers.Control.UTFGrid"
});
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