87 lines
3 KiB
JavaScript
87 lines
3 KiB
JavaScript
/* Copyright (c) 2011 by MapQuery Contributors (see AUTHORS for
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* full list of contributors). Published under the MIT license.
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* See https://github.com/mapquery/mapquery/blob/master/LICENSE for the
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* full text of the license. */
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/**
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#jquery.mapquery.legend.js
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A plugin on mapquery.core to add a legend to a layer. It will check if the layer
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is within a valid extent and zoom range. And if not will return an error message.
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*/
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(function($, MQ) {
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$.extend( $.fn.mapQuery.defaults.layer.all, {
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legend: {
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url: '',
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msg: ''
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}
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});
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//possible error messages to display in the legend
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LEGEND_ERRORS= ['E_ZOOMOUT', 'E_ZOOMIN', 'E_OUTSIDEBOX'];
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$.extend(MQ.Layer.prototype, {
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/**
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###**layer**.`legend([options])`
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_version added 0.1_
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####**Description**: get/set the legend of a layer
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**options** url:url the url to the legend image
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>Returns: {url:url, msg:'E\_ZOOMOUT' | 'E\_ZOOMIN' | 'E\_OUTSIDEBOX' | ''}
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The `.legend()` function allows us to attach a legend image to a layer. It will
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also check if the layer is not visible due to wrong extent or zoom level.
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It will return an error message which can be used to notify the user.
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var legend = layer.legend(); //get the current legend
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//set the legend url to legendimage.png
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layer.legend({url:'legendimage.png'})
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*/
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//get/set the legend object
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legend: function(options) {
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//get the legend object
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var center = this.map.center();
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if (arguments.length===0) {
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this._checkZoom(center);
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//if zoom = ok, check box
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if(this.options.legend.msg==''){
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this._checkBox(center);
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}
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return this.options.legend;
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}
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//set the legend url
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if (options.url!==undefined) {
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this.options.legend.url = options.url;
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return this.options.legend;
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}
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},
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//Check if the layer has a maximum box set and if the current box
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//is outside these settings, set the legend.msg accordingly
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_checkBox: function(center){
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var maxExtent = this.options.maxExtent;
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if(maxExtent!==undefined) {
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var mapBounds = new OpenLayers.Bounds(
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center.box[0],center.box[1],center.box[2],center.box[3]);
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var layerBounds = new OpenLayers.Bounds(
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maxExtent[0],maxExtent[1],maxExtent[2],maxExtent[3]);
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var inside = layerBounds.containsBounds(mapBounds, true);
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this.options.legend.msg = inside?'':LEGEND_ERRORS[2];
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}
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},
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//Check if the layer has a minimum or maximum zoom set and if the
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//current zoom is outside these settings, set the legend.msg accordingly
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_checkZoom: function(center){
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var zoom = center.zoom;
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var maxZoom = this.options.maxZoom;
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var minZoom = this.options.minZoom;
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this.options.legend.msg=(
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maxZoom!==undefined&&maxZoom<zoom)? LEGEND_ERRORS[0]:'';
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this.options.legend.msg=(
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minZoom!==undefined&&minZoom>zoom)? LEGEND_ERRORS[1]:'';
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}
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});
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})(jQuery, $.MapQuery);
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