Different colors for labels based on their hash

webui: A hash is computed on each label, which is then used to determine
the label's color.

3 files changed, 144 insertions, 86 deletions

diff --git a/webui/src/Label.js b/webui/src/Label.js
index 93a9a358..8981142d 100644
--- a/webui/src/Label.js
+++ b/webui/src/Label.js
@@ -1,15 +1,64 @@
-import React from 'react'
-import { withStyles } from '@material-ui/core/styles'
+import React from "react";
+import { withStyles } from "@material-ui/core/styles";
+import {
+  getContrastRatio,
+  darken
+} from "@material-ui/core/styles/colorManipulator";
+import * as allColors from "@material-ui/core/colors";
+import { common } from "@material-ui/core/colors";
+
+// JS's modulo returns negative numbers sometimes.
+// This ensures the result is positive.
+const mod = (n, m) => ((n % m) + m) % m;
+
+// Minimum contrast between the background and the text color
+const contrastThreshold = 2.5;
+
+// Filter out the "common" color
+const labelColors = Object.entries(allColors)
+  .filter(([key, value]) => value !== common)
+  .map(([key, value]) => value);
+
+// Generate a hash (number) from a string
+const hash = string =>
+  string.split("").reduce((a, b) => ((a << 5) - a + b.charCodeAt(0)) | 0, 0);
+
+// Get the background color from the label
+const getColor = label =>
+  labelColors[mod(hash(label), labelColors.length)][500];
+
+// Guess the text color based on the background color
+const getTextColor = background =>
+  getContrastRatio(background, common.white) >= contrastThreshold
+    ? common.white // White on dark backgrounds
+    : common.black; // And black on light ones
+
+const _genStyle = background => ({
+  backgroundColor: background,
+  color: getTextColor(background),
+  borderBottomColor: darken(background, 0.2)
+});
+
+// Generate a style object (text, background and border colors) from the label
+const genStyle = label => _genStyle(getColor(label));
 
 const styles = theme => ({
   label: {
-    padding: '0 4px',
-    margin: '0 1px',
-    backgroundColor: '#da9898',
-    borderRadius: '3px'
-  },
-})
+    ...theme.typography.body2,
+    padding: "0 6px",
+    fontSize: "0.9em",
+    margin: "0 1px",
+    borderRadius: "3px",
+    display: "inline-block",
+    borderBottom: "solid 1.5px",
+    verticalAlign: "bottom"
+  }
+});
 
-const Label = ({label, classes}) => <span className={classes.label}>{label}</span>
+const Label = ({ label, classes }) => (
+  <span className={classes.label} style={genStyle(label)}>
+    {label}
+  </span>
+);
 
-export default withStyles(styles)(Label)
+export default withStyles(styles)(Label);
diff --git a/webui/src/bug/Bug.js b/webui/src/bug/Bug.js
index 34fc3ad4..c6edda35 100644
--- a/webui/src/bug/Bug.js
+++ b/webui/src/bug/Bug.js
@@ -1,15 +1,16 @@
-import { withStyles } from '@material-ui/core/styles'
-import Typography from '@material-ui/core/Typography/Typography'
-import gql from 'graphql-tag'
-import React from 'react'
-import Author from '../Author'
-import Date from '../Date'
-import TimelineQuery from './TimelineQuery'
+import { withStyles } from "@material-ui/core/styles";
+import Typography from "@material-ui/core/Typography/Typography";
+import gql from "graphql-tag";
+import React from "react";
+import Author from "../Author";
+import Date from "../Date";
+import TimelineQuery from "./TimelineQuery";
+import Label from "../Label";
 
 const styles = theme => ({
   main: {
     maxWidth: 600,
-    margin: 'auto',
+    margin: "auto",
     marginTop: theme.spacing.unit * 4
   },
   header: {},
@@ -18,37 +19,41 @@ const styles = theme => ({
   },
   id: {
     ...theme.typography.subheading,
-    marginLeft: 15,
+    marginLeft: 15
   },
   container: {
-    display: 'flex',
+    display: "flex",
     marginBottom: 30
   },
   timeline: {
-    width: '70%',
+    width: "70%",
     marginTop: 20,
-    marginRight: 20,
+    marginRight: 20
   },
   sidebar: {
-    width: '30%'
+    width: "30%"
+  },
+  labelList: {
+    listStyle: "none",
+    padding: 0,
+    margin: 0
   },
   label: {
-    backgroundColor: '#da9898',
-    borderRadius: '3px',
-    paddingLeft: '10px',
-    margin: '2px 20px auto 2px',
-    fontWeight: 'bold',
+    margin: "4px 0",
+    "& > *": {
+      display: "block"
+    }
   }
-})
+});
 
-const Bug = ({bug, classes}) => (
+const Bug = ({ bug, classes }) => (
   <main className={classes.main}>
     <div className={classes.header}>
       <span className={classes.title}>{bug.title}</span>
       <span className={classes.id}>{bug.humanId}</span>
 
-      <Typography color={'textSecondary'}>
-        <Author author={bug.author}/>
+      <Typography color={"textSecondary"}>
+        <Author author={bug.author} />
         <span> opened this bug </span>
         <Date date={bug.createdAt} />
       </Typography>
@@ -56,19 +61,21 @@ const Bug = ({bug, classes}) => (
 
     <div className={classes.container}>
       <div className={classes.timeline}>
-        <TimelineQuery id={bug.id}/>
+        <TimelineQuery id={bug.id} />
       </div>
       <div className={classes.sidebar}>
-        <Typography variant={'subheading'}>Labels</Typography>
-        {bug.labels.map(l => (
-          <Typography key={l} className={classes.label}>
-            {l}
-          </Typography>
-        ))}
+        <Typography variant={"subheading"}>Labels</Typography>
+        <ul className={classes.labelList}>
+          {bug.labels.map(l => (
+            <li className={classes.label}>
+              <Label label={l} key={l} />
+            </li>
+          ))}
+        </ul>
       </div>
     </div>
   </main>
-)
+);
 
 Bug.fragment = gql`
   fragment Bug on Bug {
@@ -83,6 +90,6 @@ Bug.fragment = gql`
       name
     }
   }
-`
+`;
 
-export default withStyles(styles)(Bug)
+export default withStyles(styles)(Bug);
diff --git a/webui/src/list/BugRow.js b/webui/src/list/BugRow.js
index 9f55809d..05eafe92 100644
--- a/webui/src/list/BugRow.js
+++ b/webui/src/list/BugRow.js
@@ -1,78 +1,80 @@
-import { withStyles } from '@material-ui/core/styles'
-import TableCell from '@material-ui/core/TableCell/TableCell'
-import TableRow from '@material-ui/core/TableRow/TableRow'
-import Tooltip from '@material-ui/core/Tooltip/Tooltip'
-import Typography from '@material-ui/core/Typography'
-import ErrorOutline from '@material-ui/icons/ErrorOutline'
-import gql from 'graphql-tag'
-import React from 'react'
-import { Link } from 'react-router-dom'
-import Date from '../Date'
-import Label from '../Label'
+import { withStyles } from "@material-ui/core/styles";
+import TableCell from "@material-ui/core/TableCell/TableCell";
+import TableRow from "@material-ui/core/TableRow/TableRow";
+import Tooltip from "@material-ui/core/Tooltip/Tooltip";
+import Typography from "@material-ui/core/Typography";
+import ErrorOutline from "@material-ui/icons/ErrorOutline";
+import gql from "graphql-tag";
+import React from "react";
+import { Link } from "react-router-dom";
+import Date from "../Date";
+import Label from "../Label";
 
-const Open = ({className}) => <Tooltip title="Open">
-  <ErrorOutline nativeColor='#28a745' className={className}/>
-</Tooltip>
+const Open = ({ className }) => (
+  <Tooltip title="Open">
+    <ErrorOutline nativeColor="#28a745" className={className} />
+  </Tooltip>
+);
 
-const Closed = ({className}) => <Tooltip title="Closed">
-  <ErrorOutline nativeColor='#cb2431' className={className}/>
-</Tooltip>
+const Closed = ({ className }) => (
+  <Tooltip title="Closed">
+    <ErrorOutline nativeColor="#cb2431" className={className} />
+  </Tooltip>
+);
 
-const Status = ({status, className}) => {
+const Status = ({ status, className }) => {
   switch (status) {
-    case 'OPEN':
-      return <Open className={className}/>
-    case 'CLOSED':
-      return <Closed className={className}/>
+    case "OPEN":
+      return <Open className={className} />;
+    case "CLOSED":
+      return <Closed className={className} />;
     default:
-      return 'unknown status ' + status
+      return "unknown status " + status;
   }
-}
+};
 
 const styles = theme => ({
   cell: {
-    display: 'flex',
-    alignItems: 'center',
-    '& a': {
-      textDecoration: 'none'
+    display: "flex",
+    alignItems: "center",
+    "& a": {
+      textDecoration: "none"
     }
   },
   status: {
     margin: 10
   },
   expand: {
-    width: '100%'
+    width: "100%"
   },
   title: {
-    display: 'inline',
+    display: "inline"
   },
   labels: {
-    ...theme.typography.body2,
-    display: 'inline',
-    paddingLeft: theme.spacing.unit,
+    paddingLeft: theme.spacing.unit
   }
-})
+});
 
-const BugRow = ({bug, classes}) => (
+const BugRow = ({ bug, classes }) => (
   <TableRow hover>
     <TableCell className={classes.cell}>
-      <Status status={bug.status} className={classes.status}/>
+      <Status status={bug.status} className={classes.status} />
       <div className={classes.expand}>
-        <Link to={'bug/' + bug.humanId}>
+        <Link to={"bug/" + bug.humanId}>
           <div className={classes.expand}>
-            <Typography variant={'title'} className={classes.title}>
+            <Typography variant={"title"} className={classes.title}>
               {bug.title}
             </Typography>
-            { bug.labels.length > 0 && (
+            {bug.labels.length > 0 && (
               <span className={classes.labels}>
                 {bug.labels.map(l => (
-                  <Label key={l} label={l}/>
+                  <Label key={l} label={l} />
                 ))}
               </span>
             )}
           </div>
         </Link>
-        <Typography color={'textSecondary'}>
+        <Typography color={"textSecondary"}>
           {bug.humanId} opened
           <Date date={bug.createdAt} />
           by {bug.author.name}
@@ -80,7 +82,7 @@ const BugRow = ({bug, classes}) => (
       </div>
     </TableCell>
   </TableRow>
-)
+);
 
 BugRow.fragment = gql`
   fragment BugRow on Bug {
@@ -94,6 +96,6 @@ BugRow.fragment = gql`
       name
     }
   }
-`
+`;
 
-export default withStyles(styles)(BugRow)
+export default withStyles(styles)(BugRow);