dataSample.js
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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
var samplers = {
average: function (frame) {
var sum = 0;
var count = 0;
for (var i = 0; i < frame.length; i++) {
if (!isNaN(frame[i])) {
sum += frame[i];
count++;
}
} // Return NaN if count is 0
return count === 0 ? NaN : sum / count;
},
sum: function (frame) {
var sum = 0;
for (var i = 0; i < frame.length; i++) {
// Ignore NaN
sum += frame[i] || 0;
}
return sum;
},
max: function (frame) {
var max = -Infinity;
for (var i = 0; i < frame.length; i++) {
frame[i] > max && (max = frame[i]);
} // NaN will cause illegal axis extent.
return isFinite(max) ? max : NaN;
},
min: function (frame) {
var min = Infinity;
for (var i = 0; i < frame.length; i++) {
frame[i] < min && (min = frame[i]);
} // NaN will cause illegal axis extent.
return isFinite(min) ? min : NaN;
},
// TODO
// Median
nearest: function (frame) {
return frame[0];
}
};
var indexSampler = function (frame, value) {
return Math.round(frame.length / 2);
};
function _default(seriesType) {
return {
seriesType: seriesType,
modifyOutputEnd: true,
reset: function (seriesModel, ecModel, api) {
var data = seriesModel.getData();
var sampling = seriesModel.get('sampling');
var coordSys = seriesModel.coordinateSystem; // Only cartesian2d support down sampling
if (coordSys.type === 'cartesian2d' && sampling) {
var baseAxis = coordSys.getBaseAxis();
var valueAxis = coordSys.getOtherAxis(baseAxis);
var extent = baseAxis.getExtent(); // Coordinste system has been resized
var size = extent[1] - extent[0];
var rate = Math.round(data.count() / size);
if (rate > 1) {
var sampler;
if (typeof sampling === 'string') {
sampler = samplers[sampling];
} else if (typeof sampling === 'function') {
sampler = sampling;
}
if (sampler) {
// Only support sample the first dim mapped from value axis.
seriesModel.setData(data.downSample(data.mapDimension(valueAxis.dim), 1 / rate, sampler, indexSampler));
}
}
}
}
};
}
module.exports = _default;