Add support for rainbow and rainbowme commands

src/app/features/room/RoomInput.tsx

@@ -110,6 +110,7 @@ import { useMediaAuthentication } from '../../hooks/useMediaAuthentication';
 import { useImagePackRooms } from '../../hooks/useImagePackRooms';
 import { usePowerLevelsContext } from '../../hooks/usePowerLevels';
 import colorMXID from '../../../util/colorMXID';
+import { rainbow } from '../../../util/rainbow';
 import { useIsDirectRoom } from '../../hooks/useRoom';
 import { useAccessiblePowerTagColors, useGetMemberPowerTag } from '../../hooks/useMemberPowerTag';
 import { useRoomCreators } from '../../hooks/useRoomCreators';
@@ -318,6 +319,13 @@ export const RoomInput = forwardRef<HTMLDivElement, RoomInputProps>(
         msgType = MsgType.Emote;
       } else if (commandName === Command.Notice) {
         msgType = MsgType.Notice;
+      } else if (commandName === Command.Rainbow) {
+        plainText = rainbow(plainText);
+        customHtml = rainbow(customHtml);
+      } else if (commandName === Command.RainbowMe) {
+        plainText = rainbow(plainText);
+        customHtml = rainbow(customHtml);
+        msgType = MsgType.Emote;
       } else if (commandName === Command.Shrug) {
         plainText = `${SHRUG} ${plainText}`;
         customHtml = `${SHRUG} ${customHtml}`;

src/app/hooks/useCommands.ts

@@ -140,6 +140,8 @@ export type CommandExe = (payload: string) => Promise<void>;
 export enum Command {
   Me = 'me',
   Notice = 'notice',
+  Rainbow = 'rainbow',
+  RainbowMe = 'rainbowme',
   Shrug = 'shrug',
   StartDm = 'startdm',
   Join = 'join',
@@ -184,6 +186,16 @@ export const useCommands = (mx: MatrixClient, room: Room): CommandRecord => {
         description: 'Send notice message',
         exe: async () => undefined,
       },
+      [Command.Rainbow]: {
+        name: Command.Rainbow,
+        description: 'Send rainbow message',
+        exe: async () => undefined,
+      },
+      [Command.RainbowMe]: {
+        name: Command.RainbowMe,
+        description: 'Send rainbow action message',
+        exe: async () => undefined,
+      },
       [Command.Shrug]: {
         name: Command.Shrug,
         description: 'Send ¯\\_(ツ)_/¯ as message',

src/util/rainbow.ts

@@ -0,0 +1,81 @@
+/*
+Copyright 2019 Michael Telatynski <7t3chguy@gmail.com>
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+
+Originally obtained from:
+https://github.com/matrix-org/matrix-react-sdk/blob/develop/src/utils/colour.ts
+Revision: 526645c79160ab1ad4b4c3845de27d51263a405e
+
+Modifications made:
+- 2023-10-25: Martijn de Boer; removed lodash dependency
+- 2025-10-29: RGBCube; ignore all forms of whitespace, use data-mx-color with span, and clean
+*/
+
+const isWhitespace = (char) => /\s/.test(char);
+
+export const rainbow = (str: string) =>
+  str.split('')
+    .map((c, i) => {
+      if (isWhitespace(c)) return c;
+
+      const frequency = (2 * Math.PI) / str.length;
+      const [a, b] = generateAB(i * frequency, 1);
+
+      const [r, g, b_] = labToRGB(75, a, b);
+
+      return `<span data-mx-color='#${r.toString(16).padStart(2, '0')}${
+        g.toString(16).padStart(2, '0')
+      }${b_.toString(16).padStart(2, '0')}'>${c}</span>`;
+    })
+    .join('');
+
+const generateAB = (
+  hue: number,
+  chroma: number,
+) => [chroma * 127 * Math.cos(hue), chroma * 127 * Math.sin(hue)];
+
+const labToRGB = (l: number, a: number, b: number) => {
+  // https://en.wikipedia.org/wiki/CIELAB_color_space#Reverse_transformation
+  // https://en.wikipedia.org/wiki/SRGB#The_forward_transformation_(CIE_XYZ_to_sRGB)
+
+  // Convert CIELAB to CIEXYZ (D65)
+  let y = (l + 16) / 116;
+  const x = adjustLocation(y + a / 500) * 0.9505;
+  const z = adjustLocation(y - b / 200) * 1.089;
+
+  y = adjustLocation(y);
+
+  // Linear transformation from CIEXYZ to RGB
+  const r = 3.24096994 * x - 1.53738318 * y - 0.49861076 * z;
+  const g = -0.96924364 * x + 1.8759675 * y + 0.04155506 * z;
+  const b_ = 0.05563008 * x - 0.20397696 * y + 1.05697151 * z;
+
+  return [adjustColor(r), adjustColor(g), adjustColor(b_)];
+};
+
+const adjustLocation = (v: number) =>
+  v > 0.2069 ? Math.pow(v, 3) : 0.1284 * v - 0.01771;
+
+const adjustColor = (v: number) => {
+  const gammaCorrected = v <= 0.0031308
+    // Non-linear transformation to sRGB
+    ? 12.92 * v
+    // Normal
+    : 1.055 * Math.pow(v, 1 / 2.4) - 0.055;
+
+  // Limits number between 0 and 1
+  const limited = Math.min(Math.max(gammaCorrected, 0), 1);
+
+  return Math.round(limited * 255);
+};