ashatora/openlayers
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Providing a method to get data from the layer.

Browse Source 
I think it should be the job of the layer to retrieve data for a given location (instead of the control).  The first part of this change creates a `getData` method on the layer and updates the control to use this method.

The second part of this change removes the assumption that the data returned will be an simple object representing feature attributes.  The UTFGrid specification doesn't say anything about the structure of property values in the optional data member.  The examples given in the spec use string values.  The default callback previously assumed that the data could be rendered in a two column table.  I think it would make more sense not to make this assumption.  With this change, the user must always provide a callback to do anything with returned data.
This commit is contained in:
Tim Schaub
2012-02-25 17:33:32 -07:00
parent 55ffdffd60
commit e1dffacdde
4 changed files with 130 additions and 127 deletions
Download Patch File Download Diff File Expand all files Collapse all files

97
lib/OpenLayers/Control/UTFGrid.js
View File

@@ -31,9 +31,12 @@
* map.addLayer(world_utfgrid);
*
* var control = new OpenLayers.Control.UTFGrid({
* 'div': 'attrsdiv',
* 'layers': [world_utfgrid],
* 'handlerMode': 'move'
* layers: [world_utfgrid],
* handlerMode: 'move',
* callback: function(dataLookup) {
* // do something with returned data
*
* }
* })
* (end code)
*
@@ -58,12 +61,6 @@ OpenLayers.Control.UTFGrid = OpenLayers.Class(OpenLayers.Control, {
*/
layers: null,
/**
* Property: element
* {DOMElement}
*/
element: null,
/* Property: defaultHandlerOptions
* The default opts passed to the handler constructors
*/
@@ -147,9 +144,6 @@ OpenLayers.Control.UTFGrid = OpenLayers.Class(OpenLayers.Control, {
options = options || {};
options.handlerOptions = options.handlerOptions || this.defaultHandlerOptions;
OpenLayers.Control.prototype.initialize.apply(this, [options]);
if (options.div) {
this.element = OpenLayers.Util.getElement(options.div);
}
this.resetHandler();
},
@@ -180,90 +174,39 @@ OpenLayers.Control.UTFGrid = OpenLayers.Class(OpenLayers.Control, {
}
var layers = this.findLayers();
var globalAttrs = {};
if (layers.length > 0) {
var layer;
var dataLookup = {};
var layer, idx;
for (var i=0, len=layers.length; i<len; i++) {
layer = layers[i];
var info = layer.getTileInfo( lonLat );
var tile = info.tile;
var localAttrs = null;
var resolution = layer.utfgridResolution || 4;
if (tile !== null && typeof(tile) !== 'undefined') {
var data = tile.json
if (data !== null) {
var code = this.resolveCode(data.grid[
Math.floor((info.j) / resolution)
].charCodeAt(
Math.floor((info.i) / resolution)
));
localAttrs = data.data[data.keys[code]];
for (var property in localAttrs) {
// If attribute names collide, last one takes it
globalAttrs[property] = localAttrs[property];
}
}
}
idx = this.map.layers.indexOf(layer);
dataLookup[idx] = layer.getData(lonLat);
}
this.callback(globalAttrs); // perhaps pass tile, lonLat?
this.callback(dataLookup); // perhaps pass tile, lonLat?
}
},
/**
* APIMethod: callback
* Takes the attrs and does somethings with them
* The default behavior is to make a simple table
* and write to a div (defined by this.element)
* Function to be called when a mouse event corresponds with a location that
* includes data in one of the configured UTFGrid layers.
*
* Parameters:
* attrs - {Object}
*
* Returns:
* {Boolean} - was the element updated?
* dataLookup - {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(attrs) {
if (attrs !== null && typeof(attrs) !== 'undefined') {
val = "<table>";
for(var index in attrs) {
val += "<tr><th>" + index + "</th><td>" + attrs[index] + "</td></tr>";
}
val += "</table>";
this.element.innerHTML = val;
return true;
} else {
this.element.innerHTML = '';
return false;
}
},
/**
* Method: resolveCode
* Resolve the UTF-8 encoding stored in grids to simple
* number values.
* See the [utfgrid section of the mbtiles spec](https://github.com/mapbox/mbtiles-spec/blob/master/1.1/utfgrid.md)
* for details.
*
* Parameters:
* key - {Integer}
*
* Returns:
* {Integer} Adjusted key for non-escaped chars
*/
resolveCode: function(key) {
if (key >= 93) key--;
if (key >= 35) key--;
key -= 32;
return key;
callback: function(dataLookup) {
// to be provided in the constructor
},
/**
* Method: reset
* Resets the element
* Calls the callback with null.
*/
reset: function(evt) {
this.callback(null);
if (this.element)
this.element.innerHTML = '';
},
/**

49
lib/OpenLayers/Layer/UTFGrid.js
View File

@@ -180,7 +180,7 @@ OpenLayers.Layer.UTFGrid = OpenLayers.Class(OpenLayers.Layer.Grid, {
utfgridResolution: 4,
/**
* APIMethod: getTileInfo
* Method: getTileInfo
* Get tile information for a given location at the current map resolution.
*
* Parameters:
@@ -246,6 +246,53 @@ OpenLayers.Layer.UTFGrid = OpenLayers.Class(OpenLayers.Layer.Grid, {
j: Math.floor((fy - globalRow) * this.tileSize.h)
};
},
/**
* APIProperty: getData
* Get tile data associated with a map location.
*
* Parameters:
* location - {<OpenLayers.LonLat>} map location
*
* Returns:
* {Object} The UTFGrid data corresponding to the given map location.
*/
getData: function(location) {
var info = this.getTileInfo(location);
var tile = info.tile;
var data;
if (tile) {
var resolution = this.utfgridResolution;
var json = tile.json
if (json) {
var code = this.resolveCode(json.grid[
Math.floor((info.j) / resolution)
].charCodeAt(
Math.floor((info.i) / resolution)
));
data = json.data[json.keys[code]];
}
}
return data;
},
/**
* Method: resolveCode
* Resolve the UTF-8 encoding stored in grids to simple number values.
* See the UTFGrid spec for details.
*
* Parameters:
* key - {Integer}
*
* Returns:
* {Integer} Adjusted key for non-escaped chars
*/
resolveCode: function(key) {
if (key >= 93) key--;
if (key >= 35) key--;
key -= 32;
return key;
},
/**
* APIProperty: tileClass