vmui: give more visually different colors to graph lines (#3656)

* feat: make more different colors of graph lines

* docs/CHANGELOG.md: give more visually different colors to graph lines

app/vmui/packages/vmui/src/components/Views/GraphView/GraphView.tsx

@@ -1,9 +1,9 @@
-import React, { FC, useEffect, useMemo, useRef, useState } from "preact/compat";
+import React, { FC, useCallback, useEffect, useMemo, useRef, useState } from "preact/compat";
 import { MetricResult } from "../../../api/types";
 import LineChart from "../../Chart/LineChart/LineChart";
 import { AlignedData as uPlotData, Series as uPlotSeries } from "uplot";
 import Legend from "../../Chart/Legend/Legend";
-import { getHideSeries, getLegendItem, getSeriesItem } from "../../../utils/uplot/series";
+import { getHideSeries, getLegendItem, getSeriesItemContext } from "../../../utils/uplot/series";
 import { getLimitsYAxis, getMinMaxBuffer, getTimeSeries } from "../../../utils/uplot/axes";
 import { LegendItemType } from "../../../utils/uplot/types";
 import { TimeParams } from "../../../types";
@@ -59,6 +59,7 @@ const GraphView: FC<GraphViewProps> = ({
 }) => {
   const { timezone } = useTimeState();
   const currentStep = useMemo(() => customStep || period.step || "1s", [period.step, customStep]);
+  const getSeriesItem = useCallback(getSeriesItemContext(), [data]);
 
   const [dataChart, setDataChart] = useState<uPlotData>([[]]);
   const [series, setSeries] = useState<uPlotSeries[]>([]);

app/vmui/packages/vmui/src/utils/color.ts

@@ -1,14 +1,35 @@
-export const getColorFromString = (str: string): string => {
-  let hash = 0;
-  for (let i = 0; i < str.length; i++) {
-    hash = str.charCodeAt(i) + ((hash << 5) - hash);
+export const baseContrastColors = [
+  "#e54040",
+  "#32a9dc",
+  "#2ee329",
+  "#7126a1",
+  "#e38f0f",
+  "#3d811a",
+  "#ffea00",
+  "#2d2d2d",
+  "#da42a6",
+  "#a44e0c",
+];
+
+export const getColorFromString = (text: string): string => {
+  const SEED = 16777215;
+  const FACTOR = 49979693;
+
+  let b = 1;
+  let d = 0;
+  let f = 1;
+
+  if (text.length > 0) {
+    for (let i = 0; i < text.length; i++) {
+      text[i].charCodeAt(0) > d && (d = text[i].charCodeAt(0));
+      f = parseInt(String(SEED / d));
+      b = (b + text[i].charCodeAt(0) * f * FACTOR) % SEED;
+    }
   }
-  let colour = "#";
-  for (let i = 0; i < 3; i++) {
-    const value = (hash >> (i * 8)) & 0xFF;
-    colour += ("00" + value.toString(16)).substr(-2);
-  }
-  return colour;
+
+  let hex = ((b * text.length) % SEED).toString(16);
+  hex = hex.padEnd(6, hex);
+  return `#${hex}`;
 };
 
 export const hexToRGB = (hex: string): string => {

app/vmui/packages/vmui/src/utils/uplot/helpers.ts

@@ -1,5 +1,4 @@
 import uPlot, { Axis } from "uplot";
-import { getColorFromString } from "../color";
 
 export const defaultOptions = {
   legend: {
@@ -85,6 +84,4 @@ export const sizeAxis = (u: uPlot, values: string[], axisIdx: number, cycleNum:
   return Math.ceil(axisSize);
 };
 
-export const getColorLine = (label: string): string => getColorFromString(label);
-
 export const getDashLine = (group: number): number[] => group <= 1 ? [] : [group*4, group*1.2];

app/vmui/packages/vmui/src/utils/uplot/series.ts

@@ -2,26 +2,34 @@ import { MetricResult } from "../../api/types";
 import { Series } from "uplot";
 import { getNameForMetric } from "../metric";
 import { BarSeriesItem, Disp, Fill, LegendItemType, Stroke } from "./types";
-import { getColorLine } from "./helpers";
 import { HideSeriesArgs } from "./types";
+import { baseContrastColors, getColorFromString } from "../color";
 
 interface SeriesItem extends Series {
   freeFormFields: {[key: string]: string};
 }
 
-export const getSeriesItem = (d: MetricResult, hideSeries: string[], alias: string[]): SeriesItem => {
-  const label = getNameForMetric(d, alias[d.group - 1]);
-  return {
-    label,
-    freeFormFields: d.metric,
-    width: 1.4,
-    stroke: getColorLine(label),
-    show: !includesHideSeries(label, hideSeries),
-    scale: "1",
-    points: {
-      size: 4.2,
-      width: 1.4
-    }
+export const getSeriesItemContext = () => {
+  const colorState: {[key: string]: string} = {};
+
+  return (d: MetricResult, hideSeries: string[], alias: string[]): SeriesItem => {
+    const label = getNameForMetric(d, alias[d.group - 1]);
+    const countSavedColors = Object.keys(colorState).length;
+    const hasBasicColors = countSavedColors < baseContrastColors.length;
+    if (hasBasicColors) colorState[label] = colorState[label] || baseContrastColors[countSavedColors];
+
+    return {
+      label,
+      freeFormFields: d.metric,
+      width: 1.4,
+      stroke: colorState[label] || getColorFromString(label),
+      show: !includesHideSeries(label, hideSeries),
+      scale: "1",
+      points: {
+        size: 4.2,
+        width: 1.4
+      }
+    };
   };
 };
 

docs/CHANGELOG.md

@@ -17,6 +17,7 @@ The following tip changes can be tested by building VictoriaMetrics components f
 
 * FEATURE: [vmui](https://docs.victoriametrics.com/#vmui): add ability to show custom dashboards at vmui by specifying a path to a directory with dashboard config files via `-vmui.customDashboardsPath` command-line flag. See [this feature request](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3322) and [these docs](https://github.com/VictoriaMetrics/VictoriaMetrics/tree/master/app/vmui/packages/vmui/public/dashboards).
 * FEATURE: [vmui](https://docs.victoriametrics.com/#vmui): apply the `step` globally to all the displayed graphs. See [this feature request](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3574).
+* FEATURE: [vmui](https://docs.victoriametrics.com/#vmui): improve the appearance of graph lines by using more visually distinct colors. See [this feature request](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3656).
 
 * BUGFIX: do not slow down concurrently executed queries during assisted merges, since assisted merges already prioritize data ingestion over queries. The probability of assisted merges has been increased starting from [v1.85.0](https://docs.victoriametrics.com/CHANGELOG.html#v1850) because of internal refactoring. This could result in slowed down queries when there is a plenty of free CPU resources. See [this](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3647) and [this](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3641) issues.
 * BUGFIX: reduce the increased CPU usage at `vmselect` to v1.85.3 level when processing heavy queries. See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3641).