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158 lines
4.0 KiB
158 lines
4.0 KiB
import { getDataMinMax } from './time_series2'; |
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/** |
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* Calculate tick step. |
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* Implementation from d3-array (ticks.js) |
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* https://github.com/d3/d3-array/blob/master/src/ticks.js |
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* @param start Start value |
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* @param stop End value |
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* @param count Ticks count |
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*/ |
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export function tickStep(start: number, stop: number, count: number): number { |
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let e10 = Math.sqrt(50), |
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e5 = Math.sqrt(10), |
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e2 = Math.sqrt(2); |
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let step0 = Math.abs(stop - start) / Math.max(0, count), |
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step1 = Math.pow(10, Math.floor(Math.log(step0) / Math.LN10)), |
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error = step0 / step1; |
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if (error >= e10) { |
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step1 *= 10; |
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} else if (error >= e5) { |
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step1 *= 5; |
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} else if (error >= e2) { |
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step1 *= 2; |
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} |
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return stop < start ? -step1 : step1; |
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} |
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export function getScaledDecimals(decimals, tick_size) { |
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return decimals - Math.floor(Math.log(tick_size) / Math.LN10); |
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} |
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/** |
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* Calculate tick size based on min and max values, number of ticks and precision. |
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* Implementation from Flot. |
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* @param min Axis minimum |
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* @param max Axis maximum |
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* @param noTicks Number of ticks |
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* @param tickDecimals Tick decimal precision |
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*/ |
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export function getFlotTickSize(min: number, max: number, noTicks: number, tickDecimals: number) { |
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var delta = (max - min) / noTicks, |
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dec = -Math.floor(Math.log(delta) / Math.LN10), |
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maxDec = tickDecimals; |
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var magn = Math.pow(10, -dec), |
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norm = delta / magn, // norm is between 1.0 and 10.0 |
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size; |
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if (norm < 1.5) { |
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size = 1; |
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} else if (norm < 3) { |
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size = 2; |
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// special case for 2.5, requires an extra decimal |
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if (norm > 2.25 && (maxDec == null || dec + 1 <= maxDec)) { |
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size = 2.5; |
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++dec; |
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} |
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} else if (norm < 7.5) { |
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size = 5; |
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} else { |
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size = 10; |
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} |
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size *= magn; |
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return size; |
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} |
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/** |
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* Calculate axis range (min and max). |
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* Implementation from Flot. |
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*/ |
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export function getFlotRange(panelMin, panelMax, datamin, datamax) { |
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const autoscaleMargin = 0.02; |
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let min = +(panelMin != null ? panelMin : datamin); |
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let max = +(panelMax != null ? panelMax : datamax); |
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let delta = max - min; |
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if (delta === 0.0) { |
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// Grafana fix: wide Y min and max using increased wideFactor |
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// when all series values are the same |
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var wideFactor = 0.25; |
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var widen = Math.abs(max === 0 ? 1 : max * wideFactor); |
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if (panelMin === null) { |
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min -= widen; |
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} |
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// always widen max if we couldn't widen min to ensure we |
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// don't fall into min == max which doesn't work |
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if (panelMax == null || panelMin != null) { |
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max += widen; |
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} |
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} else { |
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// consider autoscaling |
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var margin = autoscaleMargin; |
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if (margin != null) { |
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if (panelMin == null) { |
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min -= delta * margin; |
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// make sure we don't go below zero if all values |
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// are positive |
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if (min < 0 && datamin != null && datamin >= 0) { |
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min = 0; |
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} |
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} |
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if (panelMax == null) { |
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max += delta * margin; |
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if (max > 0 && datamax != null && datamax <= 0) { |
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max = 0; |
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} |
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} |
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} |
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} |
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return { min, max }; |
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} |
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/** |
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* Calculate tick decimals. |
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* Implementation from Flot. |
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*/ |
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export function getFlotTickDecimals(data, axis) { |
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let { datamin, datamax } = getDataMinMax(data); |
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let { min, max } = getFlotRange(axis.min, axis.max, datamin, datamax); |
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let noTicks = 3; |
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let tickDecimals, maxDec; |
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let delta = (max - min) / noTicks; |
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let dec = -Math.floor(Math.log(delta) / Math.LN10); |
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let magn = Math.pow(10, -dec); |
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// norm is between 1.0 and 10.0 |
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let norm = delta / magn; |
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let size; |
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if (norm < 1.5) { |
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size = 1; |
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} else if (norm < 3) { |
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size = 2; |
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// special case for 2.5, requires an extra decimal |
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if (norm > 2.25 && (maxDec == null || dec + 1 <= maxDec)) { |
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size = 2.5; |
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++dec; |
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} |
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} else if (norm < 7.5) { |
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size = 5; |
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} else { |
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size = 10; |
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} |
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size *= magn; |
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tickDecimals = Math.max(0, maxDec != null ? maxDec : dec); |
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// grafana addition |
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const scaledDecimals = tickDecimals - Math.floor(Math.log(size) / Math.LN10); |
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return { tickDecimals, scaledDecimals }; |
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}
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