Sync theia dark/light theme with electron nativeTheme setting

packages/core/src/common/theme.ts

@@ -18,6 +18,8 @@ import { URI } from 'vscode-uri';
 
 export type ThemeType = 'light' | 'dark' | 'hc' | 'hcLight';
 
+export type ThemeMode = 'light' | 'dark';
+
 export interface Theme {
     readonly id: string;
     readonly type: ThemeType;
@@ -32,6 +34,10 @@ export function isHighContrast(scheme: ThemeType): boolean {
     return scheme === 'hc' || scheme === 'hcLight';
 }
 
+export function getThemeMode(type: ThemeType): ThemeMode {
+    return (type === 'hc' || type === 'dark') ? 'dark' : 'light';
+}
+
 export interface ThemeChangeEvent {
     readonly newTheme: Theme;
     readonly oldTheme?: Theme;

packages/core/src/electron-browser/menu/electron-menu-contribution.ts

@@ -30,7 +30,7 @@ import { WindowTitleService } from '../../browser/window/window-title-service';
 
 import '../../../src/electron-browser/menu/electron-menu-style.css';
 import { ThemeService } from '../../browser/theming';
-import { ThemeChangeEvent } from '../../common/theme';
+import { getThemeMode, ThemeChangeEvent } from '../../common/theme';
 
 export namespace ElectronCommands {
     export const TOGGLE_DEVELOPER_TOOLS = Command.toDefaultLocalizedCommand({
@@ -424,6 +424,7 @@ export class ElectronMenuContribution extends BrowserMenuBarContribution impleme
     protected handleThemeChange(e: ThemeChangeEvent): void {
         const backgroundColor = window.getComputedStyle(document.body).backgroundColor;
         window.electronTheiaCore.setBackgroundColor(backgroundColor);
+        window.electronTheiaCore.setTheme(getThemeMode(e.newTheme.type));
     }
 
 }

packages/core/src/electron-browser/preload.ts

@@ -27,7 +27,7 @@ import {
     CHANNEL_REQUEST_RELOAD, CHANNEL_APP_STATE_CHANGED, CHANNEL_SHOW_ITEM_IN_FOLDER, CHANNEL_READ_CLIPBOARD, CHANNEL_WRITE_CLIPBOARD,
     CHANNEL_KEYBOARD_LAYOUT_CHANGED, CHANNEL_IPC_CONNECTION, InternalMenuDto, CHANNEL_REQUEST_SECONDARY_CLOSE, CHANNEL_SET_BACKGROUND_COLOR,
     CHANNEL_WC_METADATA, CHANNEL_ABOUT_TO_CLOSE, CHANNEL_OPEN_WITH_SYSTEM_APP,
-    CHANNEL_OPEN_URL
+    CHANNEL_OPEN_URL, CHANNEL_SET_THEME
 } from '../electron-common/electron-api';
 
 // eslint-disable-next-line import/no-extraneous-dependencies
@@ -120,6 +120,9 @@ const api: TheiaCoreAPI = {
     setBackgroundColor: function (backgroundColor): void {
         ipcRenderer.send(CHANNEL_SET_BACKGROUND_COLOR, backgroundColor);
     },
+    setTheme: function (theme): void {
+        ipcRenderer.send(CHANNEL_SET_THEME, theme);
+    },
     minimize: function (): void {
         ipcRenderer.send(CHANNEL_MINIMIZE);
     },

packages/core/src/electron-common/electron-api.ts

@@ -17,6 +17,7 @@
 import { NativeKeyboardLayout } from '../common/keyboard/keyboard-layout-provider';
 import { Disposable } from '../common';
 import { FrontendApplicationState, StopReason } from '../common/frontend-application-state';
+import { ThemeMode } from '../common/theme';
 
 export type MenuRole = ('undo' | 'redo' | 'cut' | 'copy' | 'paste' | 'selectAll' | 'about' | 'services' | 'hide' | 'hideOthers' | 'unhide' | 'quit');
 
@@ -65,6 +66,7 @@ export interface TheiaCoreAPI {
     getTitleBarStyleAtStartup(): Promise<string>;
     setTitleBarStyle(style: string): void;
     setBackgroundColor(backgroundColor: string): void;
+    setTheme(theme: ThemeMode): void;
     minimize(): void;
     isMaximized(): boolean; // TODO: this should really be async, since it blocks the renderer process
     maximize(): void;
@@ -125,6 +127,7 @@ export const CHANNEL_ATTACH_SECURITY_TOKEN = 'AttachSecurityToken';
 export const CHANNEL_GET_TITLE_STYLE_AT_STARTUP = 'GetTitleStyleAtStartup';
 export const CHANNEL_SET_TITLE_STYLE = 'SetTitleStyle';
 export const CHANNEL_SET_BACKGROUND_COLOR = 'SetBackgroundColor';
+export const CHANNEL_SET_THEME = 'SetTheme';
 export const CHANNEL_CLOSE = 'Close';
 export const CHANNEL_MINIMIZE = 'Minimize';
 export const CHANNEL_MAXIMIZE = 'Maximize';

packages/core/src/electron-main/electron-api-main.ts

@@ -55,7 +55,8 @@ import {
     CHANNEL_WC_METADATA,
     CHANNEL_ABOUT_TO_CLOSE,
     CHANNEL_OPEN_WITH_SYSTEM_APP,
-    CHANNEL_OPEN_URL
+    CHANNEL_OPEN_URL,
+    CHANNEL_SET_THEME
 } from '../electron-common/electron-api';
 import { ElectronMainApplication, ElectronMainApplicationContribution } from './electron-main-application';
 import { Disposable, DisposableCollection, isOSX, MaybePromise } from '../common';
@@ -176,6 +177,8 @@ export class TheiaMainApi implements ElectronMainApplicationContribution {
 
         ipcMain.on(CHANNEL_SET_BACKGROUND_COLOR, (event, backgroundColor) => application.setBackgroundColor(event.sender, backgroundColor));
 
+        ipcMain.on(CHANNEL_SET_THEME, (event, theme) => application.setTheme(theme));
+
         ipcMain.on(CHANNEL_MINIMIZE, event => {
             BrowserWindow.fromWebContents(event.sender)?.minimize();
         });

packages/core/src/electron-main/electron-main-application.ts

@@ -42,6 +42,7 @@ import { createDisposableListener } from './event-utils';
 import { TheiaRendererAPI } from './electron-api-main';
 import { StopReason } from '../common/frontend-application-state';
 import { dynamicRequire } from '../node/dynamic-require';
+import { ThemeMode } from '../common/theme';
 
 export { ElectronMainApplicationGlobals };
 
@@ -277,6 +278,10 @@ export class ElectronMainApplication {
         this.saveState(webContents);
     }
 
+    public setTheme(theme: ThemeMode): void {
+        nativeTheme.themeSource = theme;
+    }
+
     protected saveState(webContents: Electron.WebContents): void {
         const browserWindow = BrowserWindow.fromWebContents(webContents);
         if (browserWindow) {