helper.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 numberUtil = require("../util/number");
/*
* 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.
*/
/**
* For testable.
*/
var roundNumber = numberUtil.round;
/**
* @param {Array.<number>} extent Both extent[0] and extent[1] should be valid number.
* Should be extent[0] < extent[1].
* @param {number} splitNumber splitNumber should be >= 1.
* @param {number} [minInterval]
* @param {number} [maxInterval]
* @return {Object} {interval, intervalPrecision, niceTickExtent}
*/
function intervalScaleNiceTicks(extent, splitNumber, minInterval, maxInterval) {
var result = {};
var span = extent[1] - extent[0];
var interval = result.interval = numberUtil.nice(span / splitNumber, true);
if (minInterval != null && interval < minInterval) {
interval = result.interval = minInterval;
}
if (maxInterval != null && interval > maxInterval) {
interval = result.interval = maxInterval;
} // Tow more digital for tick.
var precision = result.intervalPrecision = getIntervalPrecision(interval); // Niced extent inside original extent
var niceTickExtent = result.niceTickExtent = [roundNumber(Math.ceil(extent[0] / interval) * interval, precision), roundNumber(Math.floor(extent[1] / interval) * interval, precision)];
fixExtent(niceTickExtent, extent);
return result;
}
/**
* @param {number} interval
* @return {number} interval precision
*/
function getIntervalPrecision(interval) {
// Tow more digital for tick.
return numberUtil.getPrecisionSafe(interval) + 2;
}
function clamp(niceTickExtent, idx, extent) {
niceTickExtent[idx] = Math.max(Math.min(niceTickExtent[idx], extent[1]), extent[0]);
} // In some cases (e.g., splitNumber is 1), niceTickExtent may be out of extent.
function fixExtent(niceTickExtent, extent) {
!isFinite(niceTickExtent[0]) && (niceTickExtent[0] = extent[0]);
!isFinite(niceTickExtent[1]) && (niceTickExtent[1] = extent[1]);
clamp(niceTickExtent, 0, extent);
clamp(niceTickExtent, 1, extent);
if (niceTickExtent[0] > niceTickExtent[1]) {
niceTickExtent[0] = niceTickExtent[1];
}
}
function intervalScaleGetTicks(interval, extent, niceTickExtent, intervalPrecision) {
var ticks = []; // If interval is 0, return [];
if (!interval) {
return ticks;
} // Consider this case: using dataZoom toolbox, zoom and zoom.
var safeLimit = 10000;
if (extent[0] < niceTickExtent[0]) {
ticks.push(extent[0]);
}
var tick = niceTickExtent[0];
while (tick <= niceTickExtent[1]) {
ticks.push(tick); // Avoid rounding error
tick = roundNumber(tick + interval, intervalPrecision);
if (tick === ticks[ticks.length - 1]) {
// Consider out of safe float point, e.g.,
// -3711126.9907707 + 2e-10 === -3711126.9907707
break;
}
if (ticks.length > safeLimit) {
return [];
}
} // Consider this case: the last item of ticks is smaller
// than niceTickExtent[1] and niceTickExtent[1] === extent[1].
if (extent[1] > (ticks.length ? ticks[ticks.length - 1] : niceTickExtent[1])) {
ticks.push(extent[1]);
}
return ticks;
}
exports.intervalScaleNiceTicks = intervalScaleNiceTicks;
exports.getIntervalPrecision = getIntervalPrecision;
exports.fixExtent = fixExtent;
exports.intervalScaleGetTicks = intervalScaleGetTicks;