100 lines
3.0 KiB
JavaScript
Generated
100 lines
3.0 KiB
JavaScript
Generated
/*
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* Licensed to the Apache Software Foundation (ASF) under one
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* or more contributor license agreements. See the NOTICE file
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* distributed with this work for additional information
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* regarding copyright ownership. The ASF licenses this file
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* to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing,
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* software distributed under the License is distributed on an
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* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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* KIND, either express or implied. See the License for the
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* specific language governing permissions and limitations
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* under the License.
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*/
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function decode(json) {
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if (json.UTF8Encoding) {
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return;
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}
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var jsonCompressed = json;
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var encodeScale = jsonCompressed.UTF8Scale;
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if (encodeScale == null) {
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encodeScale = 1024;
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}
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var features = jsonCompressed.features;
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features.forEach(function (feature) {
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var geometry = feature.geometry;
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var encodeOffsets = geometry.encodeOffsets;
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var coordinates = geometry.coordinates;
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// Geometry may be appeded manually in the script after json loaded.
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// In this case this geometry is usually not encoded.
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if (!encodeOffsets) {
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return;
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}
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switch (geometry.type) {
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case 'LineString':
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geometry.coordinates = decodeRing(coordinates, encodeOffsets, encodeScale);
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break;
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case 'Polygon':
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case 'MultiLineString':
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decodeRings(coordinates, encodeOffsets, encodeScale);
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break;
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case 'MultiPolygon':
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zrUtil.each(coordinates, function (rings, idx) {
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return decodeRings(rings, encodeOffsets[idx], encodeScale)
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});
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}
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});
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// Has been decoded
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jsonCompressed.UTF8Encoding = false;
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}
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function decodeRings(rings, encodeOffsets, encodeScale) {
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for (var c = 0; c < rings.length; c++) {
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rings[c] = decodeRing(
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rings[c],
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encodeOffsets[c],
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encodeScale
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);
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}
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}
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function decodeRing(coordinate, encodeOffsets, encodeScale) {
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var result = [];
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var prevX = encodeOffsets[0];
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var prevY = encodeOffsets[1];
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for (var i = 0; i < coordinate.length; i += 2) {
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var x = coordinate.charCodeAt(i) - 64;
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var y = coordinate.charCodeAt(i + 1) - 64;
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// ZigZag decoding
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x = (x >> 1) ^ (-(x & 1));
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y = (y >> 1) ^ (-(y & 1));
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// Delta deocding
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x += prevX;
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y += prevY;
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prevX = x;
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prevY = y;
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// Dequantize
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result.push([x / encodeScale, y / encodeScale]);
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}
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return result;
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}
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// Export for testing.
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if (typeof module !== 'undefined') {
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module.exports = decode;
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}
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else {
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window.decodeGeoJSON = decode;
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} |