dify/web/app/components/workflow/help-line/index.tsx

import type { HelpLineHorizontalPosition, HelpLineVerticalPosition } from './types'
import { memo } from 'react'
import { useViewport } from 'reactflow'
import { useStore } from '../store'

const HelpLineHorizontal = memo(({ top, left, width }: HelpLineHorizontalPosition) => {
  const { x, y, zoom } = useViewport()

  return (
    <div
      className="absolute z-9 h-px bg-primary-300"
      style={{
        top: top * zoom + y,
        left: left * zoom + x,
        width: width * zoom,
      }}
    />
  )
})
HelpLineHorizontal.displayName = 'HelpLineBase'

const HelpLineVertical = memo(({ top, left, height }: HelpLineVerticalPosition) => {
  const { x, y, zoom } = useViewport()

  return (
    <div
      className="absolute z-9 w-px bg-primary-300"
      style={{
        top: top * zoom + y,
        left: left * zoom + x,
        height: height * zoom,
      }}
    />
  )
})
HelpLineVertical.displayName = 'HelpLineVertical'

const HelpLine = () => {
  const helpLineHorizontal = useStore((s) => s.helpLineHorizontal)
  const helpLineVertical = useStore((s) => s.helpLineVertical)

  if (!helpLineHorizontal && !helpLineVertical) return null

  return (
    <>
      {helpLineHorizontal && <HelpLineHorizontal {...helpLineHorizontal} />}
      {helpLineVertical && <HelpLineVertical {...helpLineVertical} />}
    </>
  )
}

export default memo(HelpLine)