@mui/x-charts/internals/scales/scaleSymlog.js

The community edition of MUI X Charts components.

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.scaleSymlog = scaleSymlog;
var _d3Scale = require("@mui/x-charts-vendor/d3-scale");
/**
 * Constructs a new continuous scale with the specified range, the constant 1, the default interpolator and clamping disabled.
 * The domain defaults to [0, 1].
 * If range is not specified, it defaults to [0, 1].
 *
 * The first generic corresponds to the data type of the range elements.
 * The second generic corresponds to the data type of the output elements generated by the scale.
 * The third generic corresponds to the data type of the unknown value.
 *
 * If range element and output element type differ, the interpolator factory used with the scale must match this behavior and
 * convert the interpolated range element to a corresponding output element.
 *
 * The range must be set in accordance with the range element type.
 *
 * The interpolator factory may be set using the interpolate(...) method of the scale.
 *
 * @param range Array of range values.
 */

/**
 * Constructs a new continuous scale with the specified domain and range, the constant 1, the default interpolator and clamping disabled.
 *
 * The first generic corresponds to the data type of the range elements.
 * The second generic corresponds to the data type of the output elements generated by the scale.
 * The third generic corresponds to the data type of the unknown value.
 *
 * If range element and output element type differ, the interpolator factory used with the scale must match this behavior and
 * convert the interpolated range element to a corresponding output element.
 *
 * The range must be set in accordance with the range element type.
 *
 * The interpolator factory may be set using the interpolate(...) method of the scale.
 *
 * @param domain Array of numeric domain values.
 * @param range Array of range values.
 */

function scaleSymlog(...args) {
  const scale = (0, _d3Scale.scaleSymlog)(...args);
  const originalTicks = scale.ticks;
  const {
    negativeScale,
    linearScale,
    positiveScale
  } = generateScales(scale);

  // Workaround for https://github.com/d3/d3-scale/issues/162
  scale.ticks = count => {
    const ticks = originalTicks(count);
    const constant = scale.constant();
    let negativeLogTickCount = 0;
    let linearTickCount = 0;
    let positiveLogTickCount = 0;
    ticks.forEach(tick => {
      if (tick > -constant && tick < constant) {
        linearTickCount += 1;
      }
      if (tick <= -constant) {
        negativeLogTickCount += 1;
      }
      if (tick >= constant) {
        positiveLogTickCount += 1;
      }
    });
    const finalTicks = [];
    if (negativeLogTickCount > 0) {
      finalTicks.push(...negativeScale.ticks(negativeLogTickCount));
    }
    if (linearTickCount > 0) {
      const linearTicks = linearScale.ticks(linearTickCount);
      if (finalTicks.at(-1) === linearTicks[0]) {
        finalTicks.push(...linearTicks.slice(1));
      } else {
        finalTicks.push(...linearTicks);
      }
    }
    if (positiveLogTickCount > 0) {
      const positiveTicks = positiveScale.ticks(positiveLogTickCount);
      if (finalTicks.at(-1) === positiveTicks[0]) {
        finalTicks.push(...positiveTicks.slice(1));
      } else {
        finalTicks.push(...positiveTicks);
      }
    }
    return finalTicks;
  };
  scale.tickFormat = (count = 10, specifier) => {
    // Calculates the proportion of the domain that each scale occupies, and use that ratio to determine the number of ticks for each scale.
    const constant = scale.constant();
    const [start, end] = scale.domain();
    const extent = end - start;
    const negativeScaleDomain = negativeScale.domain();
    const negativeScaleExtent = negativeScaleDomain[1] - negativeScaleDomain[0];
    const negativeScaleRatio = extent === 0 ? 0 : negativeScaleExtent / extent;
    const negativeScaleTickCount = negativeScaleRatio * count;
    const linearScaleDomain = linearScale.domain();
    const linearScaleExtent = linearScaleDomain[1] - linearScaleDomain[0];
    const linearScaleRatio = extent === 0 ? 0 : linearScaleExtent / extent;
    const linearScaleTickCount = linearScaleRatio * count;
    const positiveScaleDomain = positiveScale.domain();
    const positiveScaleExtent = positiveScaleDomain[1] - positiveScaleDomain[0];
    const positiveScaleRatio = extent === 0 ? 0 : positiveScaleExtent / extent;
    const positiveScaleTickCount = positiveScaleRatio * count;
    const negativeTickFormat = negativeScale.tickFormat(negativeScaleTickCount, specifier);
    const linearTickFormat = linearScale.tickFormat(linearScaleTickCount, specifier);
    const positiveTickFormat = positiveScale.tickFormat(positiveScaleTickCount, specifier);
    return tick => {
      const tickFormat =
      // eslint-disable-next-line no-nested-ternary
      tick.valueOf() <= -constant ? negativeTickFormat : tick.valueOf() >= constant ? positiveTickFormat : linearTickFormat;
      return tickFormat(tick);
    };
  };

  /* Adaptation of https://github.com/d3/d3-scale/blob/d6904a4bde09e16005e0ad8ca3e25b10ce54fa0d/src/symlog.js#L30 */
  scale.copy = () => {
    return scaleSymlog(scale.domain(), scale.range()).constant(scale.constant());
  };
  return scale;
}
function generateScales(scale) {
  const constant = scale.constant();
  const domain = scale.domain();
  const negativeDomain = [domain[0], Math.min(domain[1], -constant)];
  const negativeLogScale = (0, _d3Scale.scaleLog)(negativeDomain, scale.range());
  const linearDomain = [Math.max(domain[0], -constant), Math.min(domain[1], constant)];
  const linearScale = (0, _d3Scale.scaleLinear)(linearDomain, scale.range());
  const positiveDomain = [Math.max(domain[0], constant), domain[1]];
  const positiveLogScale = (0, _d3Scale.scaleLog)(positiveDomain, scale.range());
  return {
    negativeScale: negativeLogScale,
    linearScale,
    positiveScale: positiveLogScale
  };
}