openlayers
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Build tools and sources for developing OpenLayers based mapping applications
433 lines (370 loc) • 11 kB
JavaScript
//FIXME Implement projection handling
goog.provide('ol.format.MVT');
goog.require('ol');
goog.require('ol.asserts');
goog.require('ol.ext.PBF');
goog.require('ol.format.Feature');
goog.require('ol.format.FormatType');
goog.require('ol.geom.GeometryLayout');
goog.require('ol.geom.GeometryType');
goog.require('ol.geom.LineString');
goog.require('ol.geom.MultiLineString');
goog.require('ol.geom.MultiPoint');
goog.require('ol.geom.MultiPolygon');
goog.require('ol.geom.Point');
goog.require('ol.geom.Polygon');
goog.require('ol.geom.flat.orient');
goog.require('ol.proj.Projection');
goog.require('ol.proj.Units');
goog.require('ol.render.Feature');
/**
* @classdesc
* Feature format for reading data in the Mapbox MVT format.
*
* @constructor
* @extends {ol.format.Feature}
* @param {olx.format.MVTOptions=} opt_options Options.
* @api
*/
ol.format.MVT = function(opt_options) {
ol.format.Feature.call(this);
var options = opt_options ? opt_options : {};
/**
* @type {ol.proj.Projection}
*/
this.defaultDataProjection = new ol.proj.Projection({
code: 'EPSG:3857',
units: ol.proj.Units.TILE_PIXELS
});
/**
* @private
* @type {function((ol.geom.Geometry|Object.<string,*>)=)|
* function(ol.geom.GeometryType,Array.<number>,
* (Array.<number>|Array.<Array.<number>>),Object.<string,*>,number)}
*/
this.featureClass_ = options.featureClass ?
options.featureClass : ol.render.Feature;
/**
* @private
* @type {string|undefined}
*/
this.geometryName_ = options.geometryName;
/**
* @private
* @type {string}
*/
this.layerName_ = options.layerName ? options.layerName : 'layer';
/**
* @private
* @type {Array.<string>}
*/
this.layers_ = options.layers ? options.layers : null;
/**
* @private
* @type {ol.Extent}
*/
this.extent_ = null;
};
ol.inherits(ol.format.MVT, ol.format.Feature);
/**
* Reader callbacks for parsing the PBF.
* @type {Object.<string, function(number, Object, ol.ext.PBF)>}
*/
ol.format.MVT.pbfReaders_ = {
layers: function(tag, layers, pbf) {
if (tag === 3) {
var layer = {
keys: [],
values: [],
features: []
};
var end = pbf.readVarint() + pbf.pos;
pbf.readFields(ol.format.MVT.pbfReaders_.layer, layer, end);
layer.length = layer.features.length;
if (layer.length) {
layers[layer.name] = layer;
}
}
},
layer: function(tag, layer, pbf) {
if (tag === 15) {
layer.version = pbf.readVarint();
} else if (tag === 1) {
layer.name = pbf.readString();
} else if (tag === 5) {
layer.extent = pbf.readVarint();
} else if (tag === 2) {
layer.features.push(pbf.pos);
} else if (tag === 3) {
layer.keys.push(pbf.readString());
} else if (tag === 4) {
var value = null;
var end = pbf.readVarint() + pbf.pos;
while (pbf.pos < end) {
tag = pbf.readVarint() >> 3;
value = tag === 1 ? pbf.readString() :
tag === 2 ? pbf.readFloat() :
tag === 3 ? pbf.readDouble() :
tag === 4 ? pbf.readVarint64() :
tag === 5 ? pbf.readVarint() :
tag === 6 ? pbf.readSVarint() :
tag === 7 ? pbf.readBoolean() : null;
}
layer.values.push(value);
}
},
feature: function(tag, feature, pbf) {
if (tag == 1) {
feature.id = pbf.readVarint();
} else if (tag == 2) {
var end = pbf.readVarint() + pbf.pos;
while (pbf.pos < end) {
var key = feature.layer.keys[pbf.readVarint()];
var value = feature.layer.values[pbf.readVarint()];
feature.properties[key] = value;
}
} else if (tag == 3) {
feature.type = pbf.readVarint();
} else if (tag == 4) {
feature.geometry = pbf.pos;
}
}
};
/**
* Read a raw feature from the pbf offset stored at index `i` in the raw layer.
* @suppress {missingProperties}
* @private
* @param {ol.ext.PBF} pbf PBF.
* @param {Object} layer Raw layer.
* @param {number} i Index of the feature in the raw layer's `features` array.
* @return {Object} Raw feature.
*/
ol.format.MVT.readRawFeature_ = function(pbf, layer, i) {
pbf.pos = layer.features[i];
var end = pbf.readVarint() + pbf.pos;
var feature = {
layer: layer,
type: 0,
properties: {}
};
pbf.readFields(ol.format.MVT.pbfReaders_.feature, feature, end);
return feature;
};
/**
* Read the raw geometry from the pbf offset stored in a raw feature's geometry
* proeprty.
* @suppress {missingProperties}
* @private
* @param {ol.ext.PBF} pbf PBF.
* @param {Object} feature Raw feature.
* @param {Array.<number>} flatCoordinates Array to store flat coordinates in.
* @param {Array.<number>} ends Array to store ends in.
*/
ol.format.MVT.readRawGeometry_ = function(pbf, feature, flatCoordinates, ends) {
pbf.pos = feature.geometry;
var end = pbf.readVarint() + pbf.pos;
var cmd = 1;
var length = 0;
var x = 0;
var y = 0;
var coordsLen = 0;
var currentEnd = 0;
while (pbf.pos < end) {
if (!length) {
var cmdLen = pbf.readVarint();
cmd = cmdLen & 0x7;
length = cmdLen >> 3;
}
length--;
if (cmd === 1 || cmd === 2) {
x += pbf.readSVarint();
y += pbf.readSVarint();
if (cmd === 1) { // moveTo
if (coordsLen > currentEnd) {
ends.push(coordsLen);
currentEnd = coordsLen;
}
}
flatCoordinates.push(x, y);
coordsLen += 2;
} else if (cmd === 7) {
if (coordsLen > currentEnd) {
// close polygon
flatCoordinates.push(
flatCoordinates[currentEnd], flatCoordinates[currentEnd + 1]);
coordsLen += 2;
}
} else {
ol.asserts.assert(false, 59); // Invalid command found in the PBF
}
}
if (coordsLen > currentEnd) {
ends.push(coordsLen);
currentEnd = coordsLen;
}
};
/**
* @suppress {missingProperties}
* @private
* @param {number} type The raw feature's geometry type
* @param {number} numEnds Number of ends of the flat coordinates of the
* geometry.
* @return {ol.geom.GeometryType} The geometry type.
*/
ol.format.MVT.getGeometryType_ = function(type, numEnds) {
/** @type {ol.geom.GeometryType} */
var geometryType;
if (type === 1) {
geometryType = numEnds === 1 ?
ol.geom.GeometryType.POINT : ol.geom.GeometryType.MULTI_POINT;
} else if (type === 2) {
geometryType = numEnds === 1 ?
ol.geom.GeometryType.LINE_STRING :
ol.geom.GeometryType.MULTI_LINE_STRING;
} else if (type === 3) {
geometryType = ol.geom.GeometryType.POLYGON;
// MultiPolygon not relevant for rendering - winding order determines
// outer rings of polygons.
}
return geometryType;
};
/**
* @private
* @param {ol.ext.PBF} pbf PBF
* @param {Object} rawFeature Raw Mapbox feature.
* @param {olx.format.ReadOptions=} opt_options Read options.
* @return {ol.Feature|ol.render.Feature} Feature.
*/
ol.format.MVT.prototype.createFeature_ = function(pbf, rawFeature, opt_options) {
var type = rawFeature.type;
if (type === 0) {
return null;
}
var feature;
var id = rawFeature.id;
var values = rawFeature.properties;
values[this.layerName_] = rawFeature.layer.name;
var flatCoordinates = [];
var ends = [];
ol.format.MVT.readRawGeometry_(pbf, rawFeature, flatCoordinates, ends);
var geometryType = ol.format.MVT.getGeometryType_(type, ends.length);
if (this.featureClass_ === ol.render.Feature) {
feature = new this.featureClass_(geometryType, flatCoordinates, ends, values, id);
} else {
var geom;
if (geometryType == ol.geom.GeometryType.POLYGON) {
var endss = [];
var offset = 0;
var prevEndIndex = 0;
for (var i = 0, ii = ends.length; i < ii; ++i) {
var end = ends[i];
if (!ol.geom.flat.orient.linearRingIsClockwise(flatCoordinates, offset, end, 2)) {
endss.push(ends.slice(prevEndIndex, i));
prevEndIndex = i;
}
offset = end;
}
if (endss.length > 1) {
ends = endss;
geom = new ol.geom.MultiPolygon(null);
} else {
geom = new ol.geom.Polygon(null);
}
} else {
geom = geometryType === ol.geom.GeometryType.POINT ? new ol.geom.Point(null) :
geometryType === ol.geom.GeometryType.LINE_STRING ? new ol.geom.LineString(null) :
geometryType === ol.geom.GeometryType.POLYGON ? new ol.geom.Polygon(null) :
geometryType === ol.geom.GeometryType.MULTI_POINT ? new ol.geom.MultiPoint (null) :
geometryType === ol.geom.GeometryType.MULTI_LINE_STRING ? new ol.geom.MultiLineString(null) :
null;
}
geom.setFlatCoordinates(ol.geom.GeometryLayout.XY, flatCoordinates, ends);
feature = new this.featureClass_();
if (this.geometryName_) {
feature.setGeometryName(this.geometryName_);
}
var geometry = ol.format.Feature.transformWithOptions(geom, false, this.adaptOptions(opt_options));
feature.setGeometry(geometry);
feature.setId(id);
feature.setProperties(values);
}
return feature;
};
/**
* @inheritDoc
* @api
*/
ol.format.MVT.prototype.getLastExtent = function() {
return this.extent_;
};
/**
* @inheritDoc
*/
ol.format.MVT.prototype.getType = function() {
return ol.format.FormatType.ARRAY_BUFFER;
};
/**
* @inheritDoc
* @api
*/
ol.format.MVT.prototype.readFeatures = function(source, opt_options) {
var layers = this.layers_;
var pbf = new ol.ext.PBF(/** @type {ArrayBuffer} */ (source));
var pbfLayers = pbf.readFields(ol.format.MVT.pbfReaders_.layers, {});
/** @type {Array.<ol.Feature|ol.render.Feature>} */
var features = [];
var pbfLayer;
for (var name in pbfLayers) {
if (layers && layers.indexOf(name) == -1) {
continue;
}
pbfLayer = pbfLayers[name];
var rawFeature;
for (var i = 0, ii = pbfLayer.length; i < ii; ++i) {
rawFeature = ol.format.MVT.readRawFeature_(pbf, pbfLayer, i);
features.push(this.createFeature_(pbf, rawFeature));
}
this.extent_ = pbfLayer ? [0, 0, pbfLayer.extent, pbfLayer.extent] : null;
}
return features;
};
/**
* @inheritDoc
* @api
*/
ol.format.MVT.prototype.readProjection = function(source) {
return this.defaultDataProjection;
};
/**
* Sets the layers that features will be read from.
* @param {Array.<string>} layers Layers.
* @api
*/
ol.format.MVT.prototype.setLayers = function(layers) {
this.layers_ = layers;
};
/**
* Not implemented.
* @override
*/
ol.format.MVT.prototype.readFeature = function() {};
/**
* Not implemented.
* @override
*/
ol.format.MVT.prototype.readGeometry = function() {};
/**
* Not implemented.
* @override
*/
ol.format.MVT.prototype.writeFeature = function() {};
/**
* Not implemented.
* @override
*/
ol.format.MVT.prototype.writeGeometry = function() {};
/**
* Not implemented.
* @override
*/
ol.format.MVT.prototype.writeFeatures = function() {};