From b1d576c5dac58b1eb46fc940ac48395b818fcea7 Mon Sep 17 00:00:00 2001
From: Ashley Harrison <ashley.harrison@grafana.com>
Date: Mon, 12 Jul 2021 16:53:53 +0100
Subject: [PATCH] TimeSeries: Improve tooltip positioning when tooltip
 overflows (#36440)

* TimeSeries: Improve tooltip positioning when tooltip overflows

* VizTooltip: Use react-popper, extract positioning calculation into util function + add unit tests

* VizTooltip: Keep ref as tooltipRef

* Use popper only for VizTooltip positioning

* VizTooltip: Set altAxis to true to prevent overflow on y axis

Co-authored-by: Dominik Prokop <dominik.prokop@grafana.com>
---
 .../src/components/VizTooltip/VizTooltip.tsx  |  25 +----
 .../VizTooltip/VizTooltipContainer.tsx        | 103 ++++++------------
 2 files changed, 39 insertions(+), 89 deletions(-)

diff --git a/packages/grafana-ui/src/components/VizTooltip/VizTooltip.tsx b/packages/grafana-ui/src/components/VizTooltip/VizTooltip.tsx
index c5324bfa8aa..816038b817e 100644
--- a/packages/grafana-ui/src/components/VizTooltip/VizTooltip.tsx
+++ b/packages/grafana-ui/src/components/VizTooltip/VizTooltip.tsx
@@ -1,10 +1,7 @@
 import React from 'react';
-import { css } from '@emotion/css';
-import { Portal } from '../Portal/Portal';
 import { Dimensions, TimeZone } from '@grafana/data';
 import { FlotPosition } from '../Graph/types';
 import { VizTooltipContainer } from './VizTooltipContainer';
-import { useStyles } from '../../themes';
 import { TooltipDisplayMode } from './models.gen';
 
 // Describes active dimensions user interacts with
@@ -49,30 +46,14 @@ export interface VizTooltipProps {
  * @public
  */
 export const VizTooltip: React.FC<VizTooltipProps> = ({ content, position, offset }) => {
-  const styles = useStyles(getStyles);
   if (position) {
     return (
-      <Portal className={styles.portal}>
-        <VizTooltipContainer position={position} offset={offset || { x: 0, y: 0 }}>
-          {content}
-        </VizTooltipContainer>
-      </Portal>
+      <VizTooltipContainer position={position} offset={offset || { x: 0, y: 0 }}>
+        {content}
+      </VizTooltipContainer>
     );
   }
   return null;
 };
 
 VizTooltip.displayName = 'VizTooltip';
-
-const getStyles = () => {
-  return {
-    portal: css`
-      position: absolute;
-      top: 0;
-      left: 0;
-      pointer-events: none;
-      width: 100%;
-      height: 100%;
-    `,
-  };
-};
diff --git a/packages/grafana-ui/src/components/VizTooltip/VizTooltipContainer.tsx b/packages/grafana-ui/src/components/VizTooltip/VizTooltipContainer.tsx
index 411693e39cb..137045fc706 100644
--- a/packages/grafana-ui/src/components/VizTooltip/VizTooltipContainer.tsx
+++ b/packages/grafana-ui/src/components/VizTooltip/VizTooltipContainer.tsx
@@ -1,9 +1,9 @@
-import React, { useState, useLayoutEffect, useRef, HTMLAttributes, useMemo } from 'react';
+import React, { useState, HTMLAttributes, useMemo } from 'react';
 import { css, cx } from '@emotion/css';
 import { useStyles2 } from '../../themes';
 import { getTooltipContainerStyles } from '../../themes/mixins';
-import useWindowSize from 'react-use/lib/useWindowSize';
-import { Dimensions2D, GrafanaTheme2 } from '@grafana/data';
+import { GrafanaTheme2 } from '@grafana/data';
+import { usePopper } from 'react-popper';
 
 /**
  * @public
@@ -24,78 +24,47 @@ export const VizTooltipContainer: React.FC<VizTooltipContainerProps> = ({
   className,
   ...otherProps
 }) => {
-  const tooltipRef = useRef<HTMLDivElement>(null);
-  const [tooltipMeasurement, setTooltipMeasurement] = useState<Dimensions2D>({ width: 0, height: 0 });
-  const { width, height } = useWindowSize();
-  const [placement, setPlacement] = useState({
-    x: positionX + offsetX,
-    y: positionY + offsetY,
-  });
-
-  const resizeObserver = useMemo(
-    () =>
-      // TS has hard time playing games with @types/resize-observer-browser, hence the ignore
-      // @ts-ignore
-      new ResizeObserver((entries) => {
-        for (let entry of entries) {
-          const tW = Math.floor(entry.contentRect.width + 2 * 8); //  adding padding until Safari supports borderBoxSize
-          const tH = Math.floor(entry.contentRect.height + 2 * 8);
-
-          if (tooltipMeasurement.width !== tW || tooltipMeasurement.height !== tH) {
-            setTooltipMeasurement({
-              width: tW,
-              height: tH,
-            });
-          }
-        }
-      }),
-    [tooltipMeasurement.height, tooltipMeasurement.width]
+  const [tooltipRef, setTooltipRef] = useState<HTMLDivElement | null>(null);
+  const virtualElement = useMemo(
+    () => ({
+      getBoundingClientRect() {
+        return { top: positionY, left: positionX, bottom: positionY, right: positionX, width: 0, height: 0 };
+      },
+    }),
+    [positionY, positionX]
   );
-
-  useLayoutEffect(() => {
-    if (tooltipRef.current) {
-      resizeObserver.observe(tooltipRef.current);
-    }
-
-    return () => {
-      resizeObserver.disconnect();
-    };
-  }, [resizeObserver]);
-
-  // Make sure tooltip does not overflow window
-  useLayoutEffect(() => {
-    let xO = 0,
-      yO = 0;
-    if (tooltipRef && tooltipRef.current) {
-      const xOverflow = width - (positionX + tooltipMeasurement.width);
-      const yOverflow = height - (positionY + tooltipMeasurement.height);
-      if (xOverflow < 0) {
-        xO = tooltipMeasurement.width;
-      }
-
-      if (yOverflow < 0) {
-        yO = tooltipMeasurement.height;
-      }
-    }
-
-    setPlacement({
-      x: positionX + offsetX - xO,
-      y: positionY + offsetY - yO,
-    });
-  }, [width, height, positionX, offsetX, positionY, offsetY, tooltipMeasurement.width, tooltipMeasurement.height]);
+  const { styles: popperStyles, attributes } = usePopper(virtualElement, tooltipRef, {
+    placement: 'bottom-start',
+    modifiers: [
+      { name: 'arrow', enabled: false },
+      {
+        name: 'preventOverflow',
+        enabled: true,
+        options: {
+          altAxis: true,
+          rootBoundary: 'viewport',
+        },
+      },
+      {
+        name: 'offset',
+        options: {
+          offset: [offsetX, offsetY],
+        },
+      },
+    ],
+  });
 
   const styles = useStyles2(getStyles);
 
   return (
     <div
-      ref={tooltipRef}
+      ref={setTooltipRef}
       style={{
-        position: 'fixed',
-        left: 0,
-        top: 0,
-        transform: `translate3d(${placement.x}px, ${placement.y}px, 0)`,
-        transition: 'all ease-out 0.1s',
+        ...popperStyles.popper,
+        display: popperStyles.popper?.transform ? 'block' : 'none',
+        transition: 'all ease-out 0.2s',
       }}
+      {...attributes.popper}
       {...otherProps}
       className={cx(styles.wrapper, className)}
     >