54 lines
1.1 KiB
JavaScript
54 lines
1.1 KiB
JavaScript
class RelativeScale {
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static scale (data, tickCount) {
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const [min, max] = RelativeScale.calculateBounds(data)
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let factor = 1
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while (true) {
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const scale = Math.pow(10, factor)
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const scaledMin = min - (min % scale)
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const scaledMax = max + (max % scale === 0 ? 0 : (scale - (max % scale)))
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const ticks = (scaledMax - scaledMin) / scale
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if (ticks + 1 <= tickCount) {
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return [scaledMin, scaledMax, scale]
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} else {
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// Too many steps between min/max, increase factor and try again
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factor++
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}
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}
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}
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static generateTicks (min, max, step) {
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const ticks = []
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for (let i = min; i <= max; i += step) {
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ticks.push(i)
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}
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return ticks
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}
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static calculateBounds (data) {
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if (data.length === 0) {
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return [0, 0]
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} else {
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let min = Number.MAX_VALUE
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let max = Number.MIN_VALUE
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for (const point of data) {
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if (point > max) {
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max = point
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}
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if (point < min) {
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min = point
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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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}
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module.exports = RelativeScale
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