# All files / components Brush.tsx

41.86% Statements 18/43
26.66% Branches 8/30
100% Functions 2/2
46.15% Lines 18/39

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    1x
     // Libraries
    import * as React from 'react'
    import {useLayoutEffect, FunctionComponent, CSSProperties} from 'react'

    import {DragEvent} from '../utils/useDragEvent'
    import {getRectDimensions} from '../utils/brush'

    const MIN_SELECTION_SIZE = 5 // pixels

    interface Props {
      event: DragEvent | null
      width: number
      height: number
      onXBrushEnd: (xRange: number[], onShiftDown?: boolean) => void
      onYBrushEnd: (yRange: number[]) => void
      onShiftClick?: (mouseEvent: React.MouseEvent) => void
    }

    export const Brush: FunctionComponent<Props> = ({
      event,
      width,
      height,
      onXBrushEnd,
      onYBrushEnd,
      onShiftClick,
    }) => {
      const isBrushing = event && event.direction

      useLayoutEffect(() => {
        if (event?.type !== 'dragend') {
          return
        }

        if (isBrushing) {
          let callback
          let p0
          let p1

          if (event.direction === 'x') {
            p0 = Math.min(event.initialX, event.x)
            p1 = Math.max(event.initialX, event.x)
            callback = onXBrushEnd
          } else if (event.direction === 'y') {
            p0 = Math.min(event.initialY, event.y)
            p1 = Math.max(event.initialY, event.y)
            callback = onYBrushEnd
          } else {
            return
          }

          Iif (p1 - p0 < MIN_SELECTION_SIZE) {
            return
          }
          // doing brush now
          callback([p0, p1], event.isShiftDown)
        } else {
          Iif (event.isShiftDown && event.mouseActionState === 'mouseUpHappened') {
            // a mouseUpHappened, so this is the equivalent of an 'onClick'
            // because brushing (dragging across an area) has not happened
            onShiftClick(event?.mouseEvent)
          }
        }
      }, [event?.type])

      if (!isBrushing || event.type === 'dragend') {
        return null
      }

      const {x, y, width: brushWidth, height: brushHeight} = getRectDimensions(
        event,
        width,
        height
      )

      const selectionStyle: CSSProperties = {
        display: event.initialX === null ? 'none' : 'inherit',
        position: 'absolute',
        left: `${x}px`,
        width: `${brushWidth}px`,
        top: `${y}px`,
        height: `${brushHeight}px`,
        opacity: 0.1,
        backgroundColor: 'aliceblue',
      }

      return <div className="giraffe-brush-selection" style={selectionStyle} />
    }

    Brush.displayName = 'Brush'