TA貢獻1934條經驗 獲得超2個贊
鼠標事件在與普通 JS 鼠標事件相同的坐標空間中返回鼠標坐標。要在系列坐標空間中獲取點擊位置，需要采取幾個步驟。
首先需要將鼠標坐標轉換為引擎坐標空間。引擎坐標空間是畫布左下角為0,0的畫布區域。這可以通過chart.engine.clientLocation2Engine(ev.clientX,ev.clientY). 這將使用圖表引擎比例返回引擎坐標空間中的事件坐標。
然后需要將其轉換為系列坐標。這可以通過translatePoint方法來完成。translatePoint可用于在兩個不同比例之間轉換點。LightningChart JS 中的比例基本上是一個坐標空間。
const m = chart.engine.clientLocation2Engine(ev.clientX, ev.clientY) const translated = translatePoint(m, chart.engine.scale, lineSeries.scale)
現在translated變量包含系列坐標空間中的點擊位置。
請參閱下面的完整代碼片段，您可以在其中拖動系列區域，并在停止拖動時將標記放置到拖動的開始和結束位置。
const {
lightningChart,
SolidLine,
SolidFill,
ColorRGBA,
AxisTickStrategies,
UIOrigins,
DataPatterns,
translatePoint,
ColorHEX
} = lcjs
const chart = lightningChart().ChartXY()
const diesel = [
{ x: 0, y: 1.52 },
{ x: 1, y: 1.52 },
{ x: 2, y: 1.52 },
{ x: 3, y: 1.58 },
{ x: 4, y: 2.00 },
{ x: 5, y: 2.00 },
{ x: 6, y: 2.00 },
{ x: 7, y: 2.00 },
{ x: 8, y: 2.26 },
{ x: 9, y: 1.90 },
{ x: 10, y: 1.90 },
{ x: 11, y: 1.90 },
{ x: 12, y: 1.90 },
{ x: 13, y: 1.60 },
{ x: 14, y: 1.60 },
{ x: 15, y: 1.60 },
{ x: 16, y: 1.00 },
{ x: 17, y: 1.00 },
{ x: 18, y: 1.00 },
{ x: 19, y: 1.74 },
{ x: 20, y: 1.47 },
{ x: 21, y: 1.47 },
{ x: 22, y: 1.47 },
{ x: 23, y: 1.74 },
{ x: 24, y: 1.74 },
{ x: 25, y: 1.74 },
{ x: 27, y: 1.5 },
{ x: 28, y: 1.5 },
{ x: 29, y: 1.5 }
]
const gasoline = [
{ x: 0, y: 1.35 },
{ x: 1, y: 1.35 },
{ x: 2, y: 1.35 },
{ x: 3, y: 1.35 },
{ x: 4, y: 1.90 },
{ x: 5, y: 1.90 },
{ x: 6, y: 1.90 },
{ x: 7, y: 1.92 },
{ x: 8, y: 1.50 },
{ x: 9, y: 1.50 },
{ x: 10, y: 1.3 },
{ x: 11, y: 1.3 },
{ x: 12, y: 1.3 },
{ x: 13, y: 1.3 },
{ x: 14, y: 1.3 },
{ x: 15, y: 1.32 },
{ x: 16, y: 1.40 },
{ x: 17, y: 1.44 },
{ x: 18, y: 1.02 },
{ x: 19, y: 1.02 },
{ x: 20, y: 1.02 },
{ x: 21, y: 1.02 },
{ x: 22, y: 1.02 },
{ x: 23, y: 1.02 },
{ x: 24, y: 1.02 },
{ x: 25, y: 1.02 },
{ x: 27, y: 1.30 },
{ x: 28, y: 1.30 },
{ x: 29, y: 1.30 }
]
const lineSeries = chart.addLineSeries({ dataPattern: DataPatterns.horizontalProgressive })
const lineSeries2 = chart.addLineSeries({ dataPattern: DataPatterns.horizontalProgressive })
lineSeries2.add(diesel.map((point) => ({ x: point.x, y: point.y })))
lineSeries.add(gasoline.map((point) => ({ x: point.x, y: point.y })))
const markerA = chart.addChartMarkerXY()
.setPointMarker((marker) => marker.setFillStyle((f => f.setColor(ColorHEX('#f00')))))
.setMouseInteractions(false)
const markerB = chart.addChartMarkerXY()
.setPointMarker((marker) => marker.setFillStyle((f => f.setColor(ColorHEX('#0f0')))))
.setMouseInteractions(false)
function getClickInSeriesScale(point, scale) {
const m = chart.engine.clientLocation2Engine(point.x, point.y)
return translatePoint(m, chart.engine.scale, scale)
}
chart.onSeriesBackgroundMouseDragStop((obj, ev, b, start) => {
let pointA = getClickInSeriesScale(start, lineSeries.scale)
let pointB = getClickInSeriesScale({x:ev.clientX,y:ev.clientY}, lineSeries.scale)
// move markes to start and end points
markerA.setPosition(pointA)
markerB.setPosition(pointB)
})
<script src="https://unpkg.com/@arction/[email protected]/dist/lcjs.iife.js"></script>
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