support new brightness scale behavior in gnome 49.2

Author: dmy3k

README.md

@@ -17,7 +17,7 @@ This extension addresses some of the above with custom implementation:
 - **Improved Algorithm**: More stable under often changing light conditions
 - **Smooth Transitions**: Gradually changes brightness to avoid jarring jumps
 - **Customizable Brightness Curves**: Configure brightness response with an interactive graph-based UI
-- **Configuration Backup/Restore**: Export settings to JSON for backup, sharing, or manual editing to create custom brightness configurations.
+- **Configuration Backup/Restore**: Export settings to JSON for backup, sharing, or manual editing to create custom brightness configurations - [example](examples/win11-brightness-config.json).
 
 # Installation
 

examples/win11-brightness-config.json

@@ -0,0 +1 @@
+{"brightness-buckets":[[0,10,0.1],[5,50,0.25],[15,100,0.4],[60,300,0.55],[150,400,0.7],[250,650,0.85],[350,10000,1]],"keyboard-backlight-levels":[1,0,0,0,0,0,0],"keyboard-idle-timeout":10}

lib/BrightnessManager.js

@@ -1,11 +1,18 @@
-import * as Main from 'resource:///org/gnome/shell/ui/main.js';
+import * as Config from 'resource:///org/gnome/shell/misc/config.js';
 import { CallbackManager } from './CallbackManager.js';
 
 // GNOME49 introduces new interface to manage brightness
 // https://gitlab.gnome.org/GNOME/gnome-shell/-/blob/gnome-49/js/misc/brightnessManager.js?ref_type=heads
 export class BrightnessManager {
-  constructor() {
-    this._manager = Main.brightnessManager;
+  constructor(brightnessManager) {
+    const [major, minor] = Config.PACKAGE_VERSION.split('.').map((x) => Number.parseInt(x));
+
+    // gnome 49.2 introduced new behavour of brightness slider in auto-brightness mode
+    // slider adjusts user preference (bias) for automatic brightness value
+    // https://gitlab.gnome.org/GNOME/gnome-shell/-/commit/30645802ef3282fe1e24bb73cb9fcf23586d593f
+    this._supportsBiasSlider = major > 49 || (major === 49 && minor >= 2);
+
+    this._manager = brightnessManager;
     this._changedSignalId = null;
     this._globalScaleSignalId = null;
     this._currentGlobalScale = null; // Keep reference for cleanup
@@ -40,16 +47,23 @@ export class BrightnessManager {
       // Listen to globalScale changes to capture user preference (e.g., hotkeys)
       // This fires even during dimming when user tries to adjust brightness
       this._currentGlobalScale = this._manager.globalScale;
-      this._globalScaleSignalId = this._currentGlobalScale.connect('notify::value', () => {
-        const userPreference = this._manager?.globalScale?.value ?? null;
-        this.onUserPreferenceChange.invoke(userPreference);
-      });
+
+      if (!this._supportsBiasSlider) {
+        this._globalScaleSignalId = this._currentGlobalScale.connect('notify::value', () => {
+          const userPreference = this._manager?.globalScale?.value ?? null;
+          this.onUserPreferenceChange.invoke(userPreference);
+        });
+      }
 
       // Listen to monitor backlight changes to detect actual brightness changes
       // This includes: manual changes, dimming, and system-initiated changes
       // Store references to the scale objects for proper cleanup
       const scales = this._manager.scales || [];
       for (const scale of scales) {
+        if (this._supportsBiasSlider) {
+          scale.value = 0.5; // set neutral bias on monitor change
+        }
+
         const signalId = scale.connect('backlights-changed', () => {
           this.onBrightnessChange.invoke(this.brightness);
         });

lib/DisplayBrightnessService.js

@@ -1,6 +1,6 @@
 import GLib from 'gi://GLib';
 import Gio from 'gi://Gio';
-import * as Config from 'resource:///org/gnome/shell/misc/config.js';
+import * as Main from 'resource:///org/gnome/shell/ui/main.js';
 import { BrightnessAnimator } from './BrightnessAnimator.js';
 import { BrightnessManager } from './BrightnessManager.js';
 import { BrightnessDbus } from './BrightnessDbus.js';
@@ -12,11 +12,9 @@ export class DisplayBrightnessService {
       schema: 'org.gnome.settings-daemon.plugins.power',
     });
 
-    const [major] = Config.PACKAGE_VERSION.split('.');
-    this.backend =
-      Number.parseInt(major) < 49
-        ? new BrightnessDbus(this._powerSettings)
-        : new BrightnessManager();
+    this.backend = Main.brightnessManager
+      ? new BrightnessManager(Main.brightnessManager)
+      : new BrightnessDbus(this._powerSettings);
 
     // Brightness animation
     this._animator = new BrightnessAnimator();

metadata.json

@@ -10,5 +10,5 @@
     "github": "dmy3k",
     "buymeacoffee": "dm3k"
   },
-  "version": 18
+  "version": 20
 }

tests/BrightnessManager.test.js

@@ -1,13 +1,15 @@
 import { describe, it, expect, beforeEach, afterEach, jest } from '@jest/globals';
 import { BrightnessManager } from '../lib/BrightnessManager.js';
 import * as Main from 'resource:///org/gnome/shell/ui/main.js';
+import * as Config from 'resource:///org/gnome/shell/misc/config.js';
 
 describe('BrightnessManager', () => {
   let manager;
 
   beforeEach(() => {
     Main.resetBrightnessManager(true);
-    manager = new BrightnessManager();
+    Config.setPackageVersion('49.2'); // Default to 49.2 for testing
+    manager = new BrightnessManager(Main.brightnessManager);
   });
 
   afterEach(() => {
@@ -55,14 +57,13 @@ describe('BrightnessManager', () => {
       expect(secondId).toBeDefined();
     });
 
-    it('should setup globalScale listener when changed signal is emitted', () => {
+    it('should setup monitor scale listeners when changed signal is emitted', () => {
       manager.connect();
 
-      // Trigger the 'changed' signal which should set up globalScale listener
+      // Trigger the 'changed' signal which should set up monitor scale listeners
       Main.brightnessManager.emit('changed');
 
-      expect(manager._globalScaleSignalId).toBeDefined();
-      expect(typeof manager._globalScaleSignalId).toBe('number');
+      expect(manager._monitorScaleSignalIds.length).toBeGreaterThan(0);
     });
   });
 
@@ -218,7 +219,7 @@ describe('BrightnessManager', () => {
       manager.connect();
       Main.brightnessManager.emit('changed'); // Set up listeners
 
-      expect(manager._globalScaleSignalId).not.toBeNull();
+      // Monitor scale listeners should always be set up
       expect(manager._monitorScaleSignalIds.length).toBeGreaterThan(0);
 
       manager.destroy();
@@ -260,4 +261,125 @@ describe('BrightnessManager', () => {
       expect(manager._manager).toBeNull();
     });
   });
+
+  describe('version-specific behavior', () => {
+    describe('GNOME 49.2+ (bias slider support)', () => {
+      beforeEach(() => {
+        Config.setPackageVersion('49.2');
+        Main.resetBrightnessManager(true);
+        manager = new BrightnessManager(Main.brightnessManager);
+      });
+
+      it('should detect GNOME 49.2+ and enable bias slider support', () => {
+        expect(manager._supportsBiasSlider).toBe(true);
+      });
+
+      it('should NOT setup globalScale value listener on GNOME 49.2+', () => {
+        manager.connect();
+        Main.brightnessManager.emit('changed');
+
+        // globalScale listener should not be set up for bias slider versions
+        expect(manager._globalScaleSignalId).toBeNull();
+      });
+
+      it('should set monitor scales to neutral bias (0.5) on monitor change', () => {
+        manager.connect();
+        Main.brightnessManager.emit('changed');
+
+        const scales = Main.brightnessManager.scales;
+        expect(scales.length).toBeGreaterThan(0);
+        for (const scale of scales) {
+          expect(scale.value).toBe(0.5);
+        }
+      });
+
+      it('should not trigger user preference callbacks', () => {
+        const callback = jest.fn();
+        manager.onUserPreferenceChange.add(callback);
+        
+        manager.connect();
+        Main.brightnessManager.emit('changed');
+        
+        // Change globalScale value
+        Main.brightnessManager.globalScale.value = 0.8;
+        
+        // Callback should NOT be invoked on 49.2+
+        expect(callback).not.toHaveBeenCalled();
+      });
+    });
+
+    describe('GNOME 49.0-49.1 (no bias slider)', () => {
+      beforeEach(() => {
+        Config.setPackageVersion('49.0');
+        Main.resetBrightnessManager(true);
+        manager = new BrightnessManager(Main.brightnessManager);
+      });
+
+      it('should detect GNOME 49.0 and disable bias slider support', () => {
+        expect(manager._supportsBiasSlider).toBe(false);
+      });
+
+      it('should setup globalScale value listener on GNOME 49.0', () => {
+        manager.connect();
+        Main.brightnessManager.emit('changed');
+
+        // globalScale listener should be set up for non-bias slider versions
+        expect(manager._globalScaleSignalId).not.toBeNull();
+        expect(typeof manager._globalScaleSignalId).toBe('number');
+      });
+
+      it('should NOT set monitor scales to neutral bias', () => {
+        manager.connect();
+        
+        // Set scales to different values before triggering change
+        const scales = Main.brightnessManager.scales;
+        const originalValue = scales[0].value;
+        
+        Main.brightnessManager.emit('changed');
+
+        // On GNOME 49.0 (no bias slider), scales should NOT be reset to 0.5
+        // They keep their original values
+        expect(scales[0].value).toBe(originalValue);
+      });
+
+      it('should trigger user preference callbacks on globalScale changes', () => {
+        const callback = jest.fn();
+        manager.onUserPreferenceChange.add(callback);
+        
+        manager.connect();
+        Main.brightnessManager.emit('changed');
+        
+        // Change globalScale value - this should trigger the callback
+        Main.brightnessManager.globalScale.value = 0.8;
+        
+        expect(callback).toHaveBeenCalledWith(0.8);
+      });
+    });
+
+    describe('GNOME 50+ (future versions)', () => {
+      beforeEach(() => {
+        Config.setPackageVersion('50.0');
+        Main.resetBrightnessManager(true);
+        manager = new BrightnessManager(Main.brightnessManager);
+      });
+
+      it('should detect GNOME 50+ and enable bias slider support', () => {
+        expect(manager._supportsBiasSlider).toBe(true);
+      });
+
+      it('should behave like GNOME 49.2+ for future versions', () => {
+        manager.connect();
+        Main.brightnessManager.emit('changed');
+
+        // Should not set up globalScale listener
+        expect(manager._globalScaleSignalId).toBeNull();
+
+        // Should set neutral bias
+        const scales = Main.brightnessManager.scales;
+        for (const scale of scales) {
+          expect(scale.value).toBe(0.5);
+        }
+      });
+    });
+  });
 });

tests/__mocks__/resource/org/gnome/shell/misc/config.js

@@ -2,4 +2,10 @@
  * Mock for GNOME Shell's config module
  */
 
-export const PACKAGE_VERSION = '49.0';
+// Default to GNOME 49.2 for testing bias slider behavior
+export let PACKAGE_VERSION = '49.2';
+
+// Helper to change version for testing
+export function setPackageVersion(version) {
+  PACKAGE_VERSION = version;
+}