@antv/t8/lib/charts/utils/scales.js

T8 is a text visualization solution for unstructured data within the AntV technology stack, and it is a declarative T8 markdown syntax that can be used to describe the content of data interpretation reports.

'use strict';

/**
 * Scaling functions for data transformation
 * Maps data values to visual coordinates
 */
/**
 * Creates a linear scale function that maps values from domain to range
 *
 * @param domain - Input range [min, max] of values to be scaled
 * @param range - Output range [min, max] that domain values will be mapped to
 * @returns A function that performs the linear scaling transformation
 */
var scaleLinear = function (domain, range) {
    return function (n) {
        var d1 = domain[0], d2 = domain[1];
        var r1 = range[0], r2 = range[1];
        // Avoid division by zero if the domain is a single point.
        // In this case, all input values will map to the start of the range.
        if (d1 === d2) {
            return r1;
        }
        // If the range is a single point, all input values will map to that point.
        if (r1 === r2) {
            return r1;
        }
        // The core linear interpolation formula.
        // It calculates the proportional position of 'n' within the domain
        // and then maps that position to the corresponding value in the range.
        return r1 + ((r2 - r1) * (n - d1)) / (d2 - d1);
    };
};
/**
 * Standalone ticks function to generate an array of uniformly spaced numbers.
 * This is needed because your scaleLinear method doesn't provide it.
 */
var ticks = function (domain, count) {
    var dMin = domain[0], dMax = domain[1];
    // Handle edge cases
    if (dMin === dMax)
        return [dMin];
    // Calculate the approximate step size
    var roughStep = (dMax - dMin) / count;
    // Find a "nice" step size based on a power of 10
    var exponent = Math.floor(Math.log10(roughStep));
    var powerOf10 = Math.pow(10, exponent);
    var niceSteps = [1, 2, 5, 10];
    var niceStep = 0;
    for (var _i = 0, niceSteps_1 = niceSteps; _i < niceSteps_1.length; _i++) {
        var s = niceSteps_1[_i];
        if (roughStep <= s * powerOf10) {
            niceStep = s * powerOf10;
            break;
        }
    }
    // Adjust for floating point inaccuracies
    if (niceStep === 0) {
        niceStep = niceSteps[niceSteps.length - 1] * powerOf10;
    }
    var result = [];
    var start = Math.floor(dMin / niceStep) * niceStep;
    var end = Math.ceil(dMax / niceStep) * niceStep;
    // Generate the ticks
    for (var current = start; current <= end; current += niceStep) {
        if (current >= dMin && current <= dMax) {
            result.push(current);
        }
    }
    return result;
};

exports.scaleLinear = scaleLinear;
exports.ticks = ticks;
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