HeatmapTooltip: Refactor to simplify upcoming PRs (#78436)

.betterer.results

@@ -1131,14 +1131,6 @@ exports[`better eslint`] = {
     "public/app/core/components/CloseButton/CloseButton.tsx:5381": [
       [0, 0, 0, "Styles should be written using objects.", "0"]
     ],
-    "public/app/core/components/ColorScale/ColorScale.tsx:5381": [
-      [0, 0, 0, "Styles should be written using objects.", "0"],
-      [0, 0, 0, "Styles should be written using objects.", "1"],
-      [0, 0, 0, "Styles should be written using objects.", "2"],
-      [0, 0, 0, "Styles should be written using objects.", "3"],
-      [0, 0, 0, "Styles should be written using objects.", "4"],
-      [0, 0, 0, "Styles should be written using objects.", "5"]
-    ],
     "public/app/core/components/Divider.tsx:5381": [
       [0, 0, 0, "Styles should be written using objects.", "0"],
       [0, 0, 0, "Styles should be written using objects.", "1"]

public/app/core/components/ColorScale/ColorScale.tsx

@@ -128,40 +128,40 @@ function clampPercent100(v: number) {
 }
 
 const getStyles = (theme: GrafanaTheme2, colors: string[]) => ({
-  scaleWrapper: css`
-    width: 100%;
-    font-size: 11px;
-    opacity: 1;
-  `,
-  scaleGradient: css`
-    background: linear-gradient(90deg, ${colors.join()});
-    height: 10px;
-    pointer-events: none;
-  `,
-  legendValues: css`
-    display: flex;
-    justify-content: space-between;
-    pointer-events: none;
-  `,
-  hoverValue: css`
-    position: absolute;
-    margin-top: -14px;
-    padding: 3px 15px;
-    background: ${theme.colors.background.primary};
-    transform: translateX(-50%);
-  `,
-  followerContainer: css`
-    position: relative;
-    pointer-events: none;
-    white-space: nowrap;
-  `,
-  follower: css`
-    position: absolute;
-    height: 14px;
-    width: 14px;
-    border-radius: 50%;
-    transform: translateX(-50%) translateY(-50%);
-    border: 2px solid ${theme.colors.text.primary};
-    margin-top: 5px;
-  `,
+  scaleWrapper: css({
+    width: '100%',
+    fontSize: '11px',
+    opacity: 1,
+  }),
+  scaleGradient: css({
+    background: `linear-gradient(90deg, ${colors.join()})`,
+    height: '10px',
+    pointerEvents: 'none',
+  }),
+  legendValues: css({
+    display: 'flex',
+    justifyContent: 'space-between',
+    pointerEvents: 'none',
+  }),
+  hoverValue: css({
+    position: 'absolute',
+    marginTop: '-14px',
+    padding: '3px 15px',
+    background: theme.colors.background.primary,
+    transform: 'translateX(-50%)',
+  }),
+  followerContainer: css({
+    position: 'relative',
+    pointerEvents: 'none',
+    whiteSpace: 'nowrap',
+  }),
+  follower: css({
+    position: 'absolute',
+    height: '14px',
+    width: '14px',
+    borderRadius: theme.shape.radius.default,
+    transform: 'translateX(-50%) translateY(-50%)',
+    border: `2px solid ${theme.colors.text.primary}`,
+    marginTop: '5px',
+  }),
 });

public/app/features/visualization/data-hover/DataHoverView.tsx

@@ -21,24 +21,27 @@ export interface Props {
   sortOrder?: SortOrder;
   mode?: TooltipDisplayMode | null;
   header?: string;
+  padding?: number;
 }
 
-interface DisplayValue {
+export interface DisplayValue {
   name: string;
   value: unknown;
   valueString: string;
   highlight: boolean;
 }
 
-export const DataHoverView = ({ data, rowIndex, columnIndex, sortOrder, mode, header = undefined }: Props) => {
-  const styles = useStyles2(getStyles);
-
-  if (!data || rowIndex == null) {
-    return null;
-  }
+export function getDisplayValuesAndLinks(
+  data: DataFrame,
+  rowIndex: number,
+  columnIndex?: number | null,
+  sortOrder?: SortOrder,
+  mode?: TooltipDisplayMode | null
+) {
   const fields = data.fields.map((f, idx) => {
     return { ...f, hovered: idx === columnIndex };
   });
+
   const visibleFields = fields.filter((f) => !Boolean(f.config.custom?.hideFrom?.tooltip));
   const traceIDField = visibleFields.find((field) => field.name === 'traceID') || fields[0];
   const orderedVisibleFields = [];
@@ -89,6 +92,24 @@ export const DataHoverView = ({ data, rowIndex, columnIndex, sortOrder, mode, he
     displayValues.sort((a, b) => arrayUtils.sortValues(sortOrder)(a.value, b.value));
   }
 
+  return { displayValues, links };
+}
+
+export const DataHoverView = ({ data, rowIndex, columnIndex, sortOrder, mode, header, padding = 0 }: Props) => {
+  const styles = useStyles2(getStyles, padding);
+
+  if (!data || rowIndex == null) {
+    return null;
+  }
+
+  const dispValuesAndLinks = getDisplayValuesAndLinks(data, rowIndex, columnIndex, sortOrder, mode);
+
+  if (dispValuesAndLinks == null) {
+    return null;
+  }
+
+  const { displayValues, links } = dispValuesAndLinks;
+
   return (
     <div className={styles.wrapper}>
       {header && (
@@ -119,9 +140,10 @@ export const DataHoverView = ({ data, rowIndex, columnIndex, sortOrder, mode, he
     </div>
   );
 };
-const getStyles = (theme: GrafanaTheme2) => {
+const getStyles = (theme: GrafanaTheme2, padding = 0) => {
   return {
     wrapper: css`
+      padding: ${padding}px;
       background: ${theme.components.tooltip.background};
       border-radius: ${theme.shape.borderRadius(2)};
     `,

public/app/plugins/panel/heatmap/HeatmapHoverView.tsx

@@ -1,4 +1,5 @@
 import React, { useEffect, useRef, useState } from 'react';
+import uPlot from 'uplot';
 
 import {
   DataFrameType,
@@ -19,6 +20,7 @@ import { isHeatmapCellsDense, readHeatmapRowsCustomMeta } from 'app/features/tra
 import { DataHoverView } from 'app/features/visualization/data-hover/DataHoverView';
 
 import { HeatmapData } from './fields';
+import { renderHistogram } from './renderHistogram';
 import { HeatmapHoverEvent } from './utils';
 
 type Props = {
@@ -37,8 +39,13 @@ export const HeatmapHoverView = (props: Props) => {
   return <HeatmapHoverCell {...props} />;
 };
 
-const HeatmapHoverCell = ({ data, hover, showHistogram, scopedVars, replaceVars }: Props) => {
+const HeatmapHoverCell = ({ data, hover, showHistogram = false, scopedVars, replaceVars }: Props) => {
   const index = hover.dataIdx;
+
+  const [isSparse] = useState(
+    () => data.heatmap?.meta?.type === DataFrameType.HeatmapCells && !isHeatmapCellsDense(data.heatmap)
+  );
+
   const xField = data.heatmap?.fields[0];
   const yField = data.heatmap?.fields[1];
   const countField = data.heatmap?.fields[2];
@@ -151,78 +158,21 @@ const HeatmapHoverCell = ({ data, hover, showHistogram, scopedVars, replaceVars
 
   let can = useRef<HTMLCanvasElement>(null);
 
-  let histCssWidth = 150;
-  let histCssHeight = 50;
-  let histCanWidth = Math.round(histCssWidth * devicePixelRatio);
-  let histCanHeight = Math.round(histCssHeight * devicePixelRatio);
+  let histCssWidth = 264;
+  let histCssHeight = 64;
+  let histCanWidth = Math.round(histCssWidth * uPlot.pxRatio);
+  let histCanHeight = Math.round(histCssHeight * uPlot.pxRatio);
 
   useEffect(
     () => {
-      if (showHistogram) {
-        let histCtx = can.current?.getContext('2d');
-
-        if (histCtx && xVals && yVals && countVals) {
-          let fromIdx = index;
-
-          while (xVals[fromIdx--] === xVals[index]) {}
-
-          fromIdx++;
-
-          let toIdx = fromIdx + data.yBucketCount!;
-
-          let maxCount = 0;
-
-          let i = fromIdx;
-          while (i < toIdx) {
-            let c = countVals[i];
-            maxCount = Math.max(maxCount, c);
-            i++;
-          }
-
-          let pHov = new Path2D();
-          let pRest = new Path2D();
-
-          i = fromIdx;
-          let j = 0;
-          while (i < toIdx) {
-            let c = countVals[i];
-
-            if (c > 0) {
-              let pctY = c / maxCount;
-              let pctX = j / (data.yBucketCount! + 1);
-
-              let p = i === index ? pHov : pRest;
-
-              p.rect(
-                Math.round(histCanWidth * pctX),
-                Math.round(histCanHeight * (1 - pctY)),
-                Math.round(histCanWidth / data.yBucketCount!),
-                Math.round(histCanHeight * pctY)
-              );
-            }
-
-            i++;
-            j++;
-          }
-
-          histCtx.clearRect(0, 0, histCanWidth, histCanHeight);
-
-          histCtx.fillStyle = '#ffffff80';
-          histCtx.fill(pRest);
-
-          histCtx.fillStyle = '#ff000080';
-          histCtx.fill(pHov);
-        }
+      if (showHistogram && xVals != null && countVals != null) {
+        renderHistogram(can, histCanWidth, histCanHeight, xVals, countVals, index, data.yBucketCount!);
       }
     },
     // eslint-disable-next-line react-hooks/exhaustive-deps
     [index]
   );
 
-  const [isSparse] = useState(
-    () => data.heatmap?.meta?.type === DataFrameType.HeatmapCells && !isHeatmapCellsDense(data.heatmap)
-  );
-
   if (isSparse) {
     return (
       <div>
@@ -258,7 +208,7 @@ const HeatmapHoverCell = ({ data, hover, showHistogram, scopedVars, replaceVars
           width={histCanWidth}
           height={histCanHeight}
           ref={can}
-          style={{ width: histCanWidth + 'px', height: histCanHeight + 'px' }}
+          style={{ width: histCssWidth + 'px', height: histCssHeight + 'px' }}
         />
       )}
       <div>

public/app/plugins/panel/heatmap/renderHistogram.tsx

@@ -0,0 +1,64 @@
+export function renderHistogram(
+  can: React.RefObject<HTMLCanvasElement>,
+  histCanWidth: number,
+  histCanHeight: number,
+  xVals: number[],
+  countVals: number[],
+  index: number,
+  yBucketCount: number
+) {
+  let histCtx = can.current?.getContext('2d');
+
+  if (histCtx != null) {
+    let fromIdx = index;
+
+    while (xVals[fromIdx--] === xVals[index]) {}
+
+    fromIdx++;
+
+    let toIdx = fromIdx + yBucketCount;
+
+    let maxCount = 0;
+
+    let i = fromIdx;
+    while (i < toIdx) {
+      let c = countVals[i];
+      maxCount = Math.max(maxCount, c);
+      i++;
+    }
+
+    let pHov = new Path2D();
+    let pRest = new Path2D();
+
+    i = fromIdx;
+    let j = 0;
+    while (i < toIdx) {
+      let c = countVals[i];
+
+      if (c > 0) {
+        let pctY = c / maxCount;
+        let pctX = j / (yBucketCount + 1);
+
+        let p = i === index ? pHov : pRest;
+
+        p.rect(
+          Math.round(histCanWidth * pctX),
+          Math.round(histCanHeight * (1 - pctY)),
+          Math.round(histCanWidth / yBucketCount),
+          Math.round(histCanHeight * pctY)
+        );
+      }
+
+      i++;
+      j++;
+    }
+
+    histCtx.clearRect(0, 0, histCanWidth, histCanHeight);
+
+    histCtx.fillStyle = '#2E3036';
+    histCtx.fill(pRest);
+
+    histCtx.fillStyle = '#5794F2';
+    histCtx.fill(pHov);
+  }
+}