Julia Friesel
59 lines
1.8 KiB
JavaScript
59 lines
1.8 KiB
JavaScript
import React from 'react'
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import { Text, View } from 'react-native'
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import config from '../../config'
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import styles from './styles'
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import { scaleObservable } from '../../local-storage'
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export function makeYAxisLabels(chartHeight) {
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const units = config.temperatureScale.units
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const scaleMax = scaleObservable.value.max
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const style = styles.yAxisLabel
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return getTickPositions(chartHeight).map((y, i) => {
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// this eyeballing is sadly necessary because RN does not
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// support percentage values for transforms, which we'd need
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// to reliably place the label vertically centered to the grid
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return (
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<Text
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style={[style, {top: y - 8}]}
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key={i}>
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{scaleMax - i * units}
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</Text>
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)
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})
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}
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export function makeHorizontalGrid(chartHeight) {
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return getTickPositions(chartHeight).map(tick => {
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return (
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<View
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top={tick}
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{...styles.horizontalGrid}
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key={tick}
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/>
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)
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})
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}
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function getTickPositions(chartHeight) {
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const units = config.temperatureScale.units
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const scaleMin = scaleObservable.value.min
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const scaleMax = scaleObservable.value.max
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const numberOfTicks = (scaleMax - scaleMin) * (1 / units) + 1
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const columnHeight = chartHeight * config.columnHeightPercentage
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const tickDistance = columnHeight / numberOfTicks
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const tickPositions = []
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const margin = tickDistance / 2
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for (let i = 0; i < numberOfTicks; i++) {
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tickPositions.push(tickDistance * i + margin)
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}
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return tickPositions
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}
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export function normalizeToScale(temp, chartHeight) {
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const scale = scaleObservable.value
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const valueRelativeToScale = (scale.max - temp) / (scale.max - scale.min)
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const scaleHeight = chartHeight * config.columnHeightPercentage
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return scaleHeight * valueRelativeToScale
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} |