Style and placement logic for usePopover()

theatre/studio/src/uiComponents/Popover/Popover.tsx

@@ -1,20 +1,24 @@
 import getStudio from '@theatre/studio/getStudio'
 import useBoundingClientRect from '@theatre/studio/uiComponents/useBoundingClientRect'
 import transparentize from 'polished/lib/color/transparentize'
-import React, {useLayoutEffect, useState} from 'react'
+import React, {useLayoutEffect, useRef, useState} from 'react'
 import {createPortal} from 'react-dom'
 import useWindowSize from 'react-use/esm/useWindowSize'
 import styled from 'styled-components'
+import PopoverArrow from './PopoverArrow'
 
 /**
  * How far from the menu should the pointer travel to auto close the menu
  */
 const defaultPointerDistanceThreshold = 200
 
+export const popoverBackgroundColor = transparentize(0.2, '#111')
+const minimumDistanceOfArrowToEdgeOfPopover = 8
+
 const Container = styled.ul`
   position: absolute;
   z-index: 10000;
-  background: ${transparentize(0.2, '#111')};
+  background: ${popoverBackgroundColor};
   color: white;
   padding: 0;
   margin: 0;
@@ -34,33 +38,57 @@ const Popover: React.FC<{
     props.pointerDistanceThreshold ?? defaultPointerDistanceThreshold
 
   const [container, setContainer] = useState<HTMLElement | null>(null)
-  const rect = useBoundingClientRect(container)
+  const arrowRef = useRef<HTMLDivElement>(null)
+
+  const containerRect = useBoundingClientRect(container)
+  const targetRect = useBoundingClientRect(props.target)
   const windowSize = useWindowSize()
 
   useLayoutEffect(() => {
-    if (!rect || !container) return
+    if (!containerRect || !container || !targetRect) return
 
-    const preferredAnchorPoint = {
-      left: rect.width / 2,
-      top: 0,
+    const gap = 8
+    const arrow = arrowRef.current!
+
+    let verticalPlacement: 'bottom' | 'top' | 'overlay' = 'bottom'
+    let top = 0
+    let left = 0
+    if (targetRect.bottom + containerRect.height + gap < windowSize.height) {
+      verticalPlacement = 'bottom'
+      top = targetRect.bottom + gap
+      arrow.style.top = '0px'
+    } else if (targetRect.top > containerRect.height + gap) {
+      verticalPlacement = 'top'
+      top = targetRect.top - (containerRect.height + gap)
+      arrow.style.bottom = '0px'
+      arrow.style.transform = 'rotateZ(180deg)'
+    } else {
+      verticalPlacement = 'overlay'
     }
 
-    const pos = {
-      left: props.clickPoint.clientX - preferredAnchorPoint.left,
-      top: props.clickPoint.clientY - preferredAnchorPoint.top,
+    let arrowLeft = 0
+    if (verticalPlacement !== 'overlay') {
+      const anchorLeft = targetRect.left + targetRect.width / 2
+      if (anchorLeft < containerRect.width / 2) {
+        left = gap
+        arrowLeft = Math.max(
+          anchorLeft - gap,
+          minimumDistanceOfArrowToEdgeOfPopover,
+        )
+      } else if (anchorLeft + containerRect.width / 2 > windowSize.width) {
+        left = windowSize.width - (gap + containerRect.width)
+        arrowLeft = Math.min(
+          anchorLeft - left,
+          containerRect.width - minimumDistanceOfArrowToEdgeOfPopover,
+        )
+      } else {
+        left = anchorLeft - containerRect.width / 2
+        arrowLeft = containerRect.width / 2
+      }
+      arrow.style.left = arrowLeft + 'px'
     }
 
-    if (pos.left < 0) {
-      pos.left = 0
-    } else if (pos.left + rect.width > windowSize.width) {
-      pos.left = windowSize.width - rect.width
-    }
-
-    if (pos.top < 0) {
-      pos.top = 0
-    } else if (pos.top + rect.height > windowSize.height) {
-      pos.top = windowSize.height - rect.height
-    }
+    const pos = {left, top}
 
     container.style.left = pos.left + 'px'
     container.style.top = pos.top + 'px'
@@ -68,9 +96,9 @@ const Popover: React.FC<{
     const onMouseMove = (e: MouseEvent) => {
       if (
         e.clientX < pos.left - pointerDistanceThreshold ||
-        e.clientX > pos.left + rect.width + pointerDistanceThreshold ||
+        e.clientX > pos.left + containerRect.width + pointerDistanceThreshold ||
         e.clientY < pos.top - pointerDistanceThreshold ||
-        e.clientY > pos.top + rect.height + pointerDistanceThreshold
+        e.clientY > pos.top + containerRect.height + pointerDistanceThreshold
       ) {
         props.onRequestClose()
       }
@@ -89,10 +117,21 @@ const Popover: React.FC<{
       window.removeEventListener('mousemove', onMouseMove)
       window.removeEventListener('mousedown', onMouseDown, {capture: true})
     }
-  }, [rect, container, props.clickPoint, windowSize, props.onRequestClose])
+  }, [
+    containerRect,
+    container,
+    props.clickPoint,
+    props.target,
+    targetRect,
+    windowSize,
+    props.onRequestClose,
+  ])
 
   return createPortal(
-    <Container ref={setContainer}>{props.children()}</Container>,
+    <Container ref={setContainer}>
+      <PopoverArrow ref={arrowRef} />
+      {props.children()}
+    </Container>,
     getStudio()!.ui.containerShadow,
   )
 }

theatre/studio/src/uiComponents/Popover/PopoverArrow.tsx

@@ -0,0 +1,38 @@
+import React, {forwardRef} from 'react'
+import {GoTriangleUp} from 'react-icons/all'
+import styled from 'styled-components'
+import {popoverBackgroundColor} from './Popover'
+
+const Container = styled.div`
+  font-size: 18px;
+  position: absolute;
+  width: 0;
+  height: 0;
+
+  color: ${() => popoverBackgroundColor};
+`
+
+const Adjust = styled.div`
+  width: 20px;
+  height: 18px;
+  position: absolute;
+  left: -10px;
+  top: -11px;
+  text-align: center;
+`
+
+type Props = {
+  className?: string
+}
+
+const PopoverArrow = forwardRef<HTMLDivElement, Props>(({className}, ref) => {
+  return (
+    <Container className={className} ref={ref}>
+      <Adjust>
+        <GoTriangleUp size={'18px'} />
+      </Adjust>
+    </Container>
+  )
+})
+
+export default PopoverArrow