sliderMove.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.
*/
/**
* Calculate slider move result.
* Usage:
* (1) If both handle0 and handle1 are needed to be moved, set minSpan the same as
* maxSpan and the same as `Math.abs(handleEnd[1] - handleEnds[0])`.
* (2) If handle0 is forbidden to cross handle1, set minSpan as `0`.
*
* @param {number} delta Move length.
* @param {Array.<number>} handleEnds handleEnds[0] can be bigger then handleEnds[1].
* handleEnds will be modified in this method.
* @param {Array.<number>} extent handleEnds is restricted by extent.
* extent[0] should less or equals than extent[1].
* @param {number|string} handleIndex Can be 'all', means that both move the two handleEnds,
* where the input minSpan and maxSpan will not work.
* @param {number} [minSpan] The range of dataZoom can not be smaller than that.
* If not set, handle0 and cross handle1. If set as a non-negative
* number (including `0`), handles will push each other when reaching
* the minSpan.
* @param {number} [maxSpan] The range of dataZoom can not be larger than that.
* @return {Array.<number>} The input handleEnds.
*/
export default function (delta, handleEnds, extent, handleIndex, minSpan, maxSpan) {
// Normalize firstly.
handleEnds[0] = restrict(handleEnds[0], extent);
handleEnds[1] = restrict(handleEnds[1], extent);
delta = delta || 0;
var extentSpan = extent[1] - extent[0];
// Notice maxSpan and minSpan can be null/undefined.
if (minSpan != null) {
minSpan = restrict(minSpan, [0, extentSpan]);
}
if (maxSpan != null) {
maxSpan = Math.max(maxSpan, minSpan != null ? minSpan : 0);
}
if (handleIndex === 'all') {
minSpan = maxSpan = Math.abs(handleEnds[1] - handleEnds[0]);
handleIndex = 0;
}
var originalDistSign = getSpanSign(handleEnds, handleIndex);
handleEnds[handleIndex] += delta;
// Restrict in extent.
var extentMinSpan = minSpan || 0;
var realExtent = extent.slice();
originalDistSign.sign < 0 ? (realExtent[0] += extentMinSpan) : (realExtent[1] -= extentMinSpan);
handleEnds[handleIndex] = restrict(handleEnds[handleIndex], realExtent);
// Expand span.
var currDistSign = getSpanSign(handleEnds, handleIndex);
if (minSpan != null && (
currDistSign.sign !== originalDistSign.sign || currDistSign.span < minSpan
)) {
// If minSpan exists, 'cross' is forbinden.
handleEnds[1 - handleIndex] = handleEnds[handleIndex] + originalDistSign.sign * minSpan;
}
// Shrink span.
var currDistSign = getSpanSign(handleEnds, handleIndex);
if (maxSpan != null && currDistSign.span > maxSpan) {
handleEnds[1 - handleIndex] = handleEnds[handleIndex] + currDistSign.sign * maxSpan;
}
return handleEnds;
}
function getSpanSign(handleEnds, handleIndex) {
var dist = handleEnds[handleIndex] - handleEnds[1 - handleIndex];
// If `handleEnds[0] === handleEnds[1]`, always believe that handleEnd[0]
// is at left of handleEnds[1] for non-cross case.
return {span: Math.abs(dist), sign: dist > 0 ? -1 : dist < 0 ? 1 : handleIndex ? -1 : 1};
}
function restrict(value, extend) {
return Math.min(extend[1], Math.max(extend[0], value));
}