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124 lines
4.7 KiB
124 lines
4.7 KiB
import { identity } from '@antv/util';
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import { Base } from './base';
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import { createInterpolateNumber, createInterpolateRound, createClamp, createNormalize, bisect, compose, d3LinearNice, isValid, } from '../utils';
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/** 当 domain 和 range 只有一段的时候的 map 的 工厂函数 */
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const createBiMap = (domain, range, createInterpolate) => {
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const [d0, d1] = domain;
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const [r0, r1] = range;
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let normalize;
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let interpolate;
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if (d0 < d1) {
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normalize = createNormalize(d0, d1);
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interpolate = createInterpolate(r0, r1);
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}
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else {
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normalize = createNormalize(d1, d0);
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interpolate = createInterpolate(r1, r0);
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}
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return compose(interpolate, normalize);
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};
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/** 当 domain 和 range 有多段时候的 map 的 工厂函数 */
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const createPolyMap = (domain, range, createInterpolate) => {
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const len = Math.min(domain.length, range.length) - 1;
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const normalizeList = new Array(len);
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const interpolateList = new Array(len);
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const reverse = domain[0] > domain[len];
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const ascendingDomain = reverse ? [...domain].reverse() : domain;
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const ascendingRange = reverse ? [...range].reverse() : range;
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// 每一段都生成 normalize 和 interpolate
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for (let i = 0; i < len; i += 1) {
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normalizeList[i] = createNormalize(ascendingDomain[i], ascendingDomain[i + 1]);
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interpolateList[i] = createInterpolate(ascendingRange[i], ascendingRange[i + 1]);
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}
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// 二分最右查找到相应的 normalize 和 interpolate
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return (x) => {
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const i = bisect(domain, x, 1, len) - 1;
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const normalize = normalizeList[i];
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const interpolate = interpolateList[i];
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return compose(interpolate, normalize)(x);
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};
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};
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/** 选择一个分段映射的函数 */
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const choosePiecewise = (domain, range, interpolate, shouldRound) => {
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const n = Math.min(domain.length, range.length);
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const createPiecewise = n > 2 ? createPolyMap : createBiMap;
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const createInterpolate = shouldRound ? createInterpolateRound : interpolate;
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return createPiecewise(domain, range, createInterpolate);
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};
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/**
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* Continuous 比例尺 的输入 x 和输出 y 满足：y = a * f(x) + b
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* 通过函数柯里化和复合函数可以在映射过程中去掉分支，提高性能。
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* 参考：https://github.com/d3/d3-scale/blob/master/src/continuous.js
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*/
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export class Continuous extends Base {
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getDefaultOptions() {
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return {
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domain: [0, 1],
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range: [0, 1],
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nice: false,
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clamp: false,
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round: false,
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interpolate: createInterpolateNumber,
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tickCount: 5,
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};
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}
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/**
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* y = interpolate(normalize(clamp(transform(x))))
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*/
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map(x) {
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if (!isValid(x))
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return this.options.unknown;
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return this.output(x);
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}
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/**
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* x = transform(clamp(interpolate(normalize(y))))
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*/
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invert(x) {
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if (!isValid(x))
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return this.options.unknown;
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return this.input(x);
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}
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nice() {
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if (!this.options.nice)
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return;
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const [min, max, tickCount, ...rest] = this.getTickMethodOptions();
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this.options.domain = this.chooseNice()(min, max, tickCount, ...rest);
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}
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getTicks() {
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const { tickMethod } = this.options;
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const [min, max, tickCount, ...rest] = this.getTickMethodOptions();
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return tickMethod(min, max, tickCount, ...rest);
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}
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getTickMethodOptions() {
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const { domain, tickCount } = this.options;
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const min = domain[0];
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const max = domain[domain.length - 1];
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return [min, max, tickCount];
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}
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chooseNice() {
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return d3LinearNice;
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}
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rescale() {
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this.nice();
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const [transform, untransform] = this.chooseTransforms();
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this.composeOutput(transform, this.chooseClamp(transform));
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this.composeInput(transform, untransform, this.chooseClamp(untransform));
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}
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chooseClamp(transform) {
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const { clamp: shouldClamp, range } = this.options;
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const domain = this.options.domain.map(transform);
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const n = Math.min(domain.length, range.length);
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return shouldClamp ? createClamp(domain[0], domain[n - 1]) : identity;
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}
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composeOutput(transform, clamp) {
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const { domain, range, round, interpolate } = this.options;
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const piecewise = choosePiecewise(domain.map(transform), range, interpolate, round);
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this.output = compose(piecewise, clamp, transform);
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}
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composeInput(transform, untransform, clamp) {
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const { domain, range } = this.options;
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const piecewise = choosePiecewise(range, domain.map(transform), createInterpolateNumber);
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this.input = compose(untransform, clamp, piecewise);
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}
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}
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//# sourceMappingURL=continuous.js.map
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