72 lines
2.7 KiB
JavaScript
72 lines
2.7 KiB
JavaScript
var AdaptiveTicker, ContinuousTicker, _, argmin, clamp, log, p,
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extend = function(child, parent) { for (var key in parent) { if (hasProp.call(parent, key)) child[key] = parent[key]; } function ctor() { this.constructor = child; } ctor.prototype = parent.prototype; child.prototype = new ctor(); child.__super__ = parent.prototype; return child; },
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hasProp = {}.hasOwnProperty;
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_ = require("underscore");
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argmin = require("./util").argmin;
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ContinuousTicker = require("./continuous_ticker");
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p = require("../../core/properties");
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clamp = function(x, min_val, max_val) {
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return Math.max(min_val, Math.min(max_val, x));
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};
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log = function(x, base) {
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if (base == null) {
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base = Math.E;
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}
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return Math.log(x) / Math.log(base);
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};
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AdaptiveTicker = (function(superClass) {
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extend(AdaptiveTicker, superClass);
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function AdaptiveTicker() {
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return AdaptiveTicker.__super__.constructor.apply(this, arguments);
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}
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AdaptiveTicker.prototype.type = 'AdaptiveTicker';
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AdaptiveTicker.define({
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base: [p.Number, 10.0],
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mantissas: [p.Array, [1, 2, 5]],
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min_interval: [p.Number, 0.0],
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max_interval: [p.Number]
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});
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AdaptiveTicker.prototype.initialize = function(attrs, options) {
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var prefix_mantissa, suffix_mantissa;
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AdaptiveTicker.__super__.initialize.call(this, attrs, options);
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prefix_mantissa = _.last(this.get('mantissas')) / this.get('base');
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suffix_mantissa = _.first(this.get('mantissas')) * this.get('base');
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this.extended_mantissas = _.flatten([prefix_mantissa, this.get('mantissas'), suffix_mantissa]);
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return this.base_factor = this.get_min_interval() === 0.0 ? 1.0 : this.get_min_interval();
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};
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AdaptiveTicker.prototype.get_interval = function(data_low, data_high, desired_n_ticks) {
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var best_mantissa, candidate_mantissas, data_range, errors, ideal_interval, ideal_magnitude, ideal_mantissa, interval, interval_exponent;
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data_range = data_high - data_low;
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ideal_interval = this.get_ideal_interval(data_low, data_high, desired_n_ticks);
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interval_exponent = Math.floor(log(ideal_interval / this.base_factor, this.get('base')));
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ideal_magnitude = Math.pow(this.get('base'), interval_exponent) * this.base_factor;
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ideal_mantissa = ideal_interval / ideal_magnitude;
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candidate_mantissas = this.extended_mantissas;
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errors = candidate_mantissas.map(function(mantissa) {
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return Math.abs(desired_n_ticks - (data_range / (mantissa * ideal_magnitude)));
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});
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best_mantissa = candidate_mantissas[argmin(errors)];
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interval = best_mantissa * ideal_magnitude;
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return clamp(interval, this.get_min_interval(), this.get_max_interval());
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};
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return AdaptiveTicker;
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})(ContinuousTicker.Model);
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module.exports = {
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Model: AdaptiveTicker
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};
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