fix(theme): add gsettings color-scheme detection for modern GTK/GNOME

commit: ffd97bd0b00d82dd6dd88538100c179c5bd84ad1
author: brice · 10mo ago · 2025-12-17 17:14 UTC
parent: 25a9d2e
signature: unsigned

2 files · +38 -2

M internal/infrastructure/webkit/injector.go +10 -1


@@ -15,12 +15,21 @@ const (
15	15		MessageHandlerName = "dumber"
16	16		)
17	17
18		-	// darkModeScript patches window.matchMedia to respect GTK's dark mode preference.
	18	+	// darkModeScript patches window.matchMedia and sets theme class on <html>.
19	19		// It must be injected at document start, after __dumber_gtk_prefers_dark is set.
20	20		const darkModeScript = `(function() {
21	21		const prefersDark = window.__dumber_gtk_prefers_dark \|\| false;
22	22		const originalMatchMedia = window.matchMedia.bind(window);
23	23
	24	+	// Apply dark/light class to document element for CSS theming
	25	+	if (prefersDark) {
	26	+	document.documentElement.classList.add('dark');
	27	+	document.documentElement.classList.remove('light');
	28	+	} else {
	29	+	document.documentElement.classList.add('light');
	30	+	document.documentElement.classList.remove('dark');
	31	+	}
	32	+
24	33		// Inject color-scheme meta tag
25	34		const meta = document.createElement('meta');
26	35		meta.name = 'color-scheme';

 	MessageHandlerName = "dumber"
 )
-// darkModeScript patches window.matchMedia to respect GTK's dark mode preference.
+// darkModeScript patches window.matchMedia and sets theme class on <html>.
 // It must be injected at document start, after __dumber_gtk_prefers_dark is set.
 const darkModeScript = `(function() {
   const prefersDark = window.__dumber_gtk_prefers_dark || false;
   const originalMatchMedia = window.matchMedia.bind(window);
+  // Apply dark/light class to document element for CSS theming
+  if (prefersDark) {
+    document.documentElement.classList.add('dark');
+    document.documentElement.classList.remove('light');
+  } else {
+    document.documentElement.classList.add('light');
+    document.documentElement.classList.remove('dark');
+  }
   // Inject color-scheme meta tag
   const meta = document.createElement('meta');
   meta.name = 'color-scheme';

M internal/ui/theme/system.go +28 -1


@@ -2,6 +2,7 @@ package theme
2	2
3	3		import (
4	4		"os"
	5	+	"os/exec"
5	6		"strings"
6	7
7	8		"github.com/jwijenbergh/puregotk/v4/gtk"

@@ -10,7 +11,8 @@ import (
10	11		// DetectSystemDarkMode checks if the system prefers dark mode.
11	12		// It checks multiple sources in order of preference:
12	13		// 1. GTK_THEME environment variable (contains "dark")
13		-	// 2. GTK Settings gtk-application-prefer-dark-theme property
	14	+	// 2. GNOME gsettings color-scheme (prefer-dark/prefer-light)
	15	+	// 3. GTK Settings gtk-application-prefer-dark-theme property
14	16		// Returns true if dark mode is preferred.
15	17		func DetectSystemDarkMode() bool {
16	18		// Check GTK_THEME environment variable first

@@ -23,6 +25,17 @@ func DetectSystemDarkMode() bool {
23	25		return false
24	26		}
25	27
	28	+	// Check GNOME gsettings color-scheme (modern GNOME/GTK4 method)
	29	+	if colorScheme := getGsettingsColorScheme(); colorScheme != "" {
	30	+	switch colorScheme {
	31	+	case "prefer-dark":
	32	+	return true
	33	+	case "prefer-light":
	34	+	return false
	35	+	// "default" falls through to next check
	36	+	}
	37	+	}
	38	+
26	39		// Try GTK Settings
27	40		settings := gtk.SettingsGetDefault()
28	41		if settings != nil {

@@ -35,6 +48,20 @@ func DetectSystemDarkMode() bool {
35	48		return true
36	49		}
37	50
	51	+	// getGsettingsColorScheme queries GNOME gsettings for the color-scheme preference.
	52	+	// Returns "prefer-dark", "prefer-light", "default", or empty string on error.
	53	+	func getGsettingsColorScheme() string {
	54	+	cmd := exec.Command("gsettings", "get", "org.gnome.desktop.interface", "color-scheme")
	55	+	output, err := cmd.Output()
	56	+	if err != nil {
	57	+	return ""
	58	+	}
	59	+	// Output is like "'prefer-dark'\n", strip quotes and whitespace
	60	+	result := strings.TrimSpace(string(output))
	61	+	result = strings.Trim(result, "'\"")
	62	+	return result
	63	+	}
	64	+
38	65		// ResolveColorScheme determines the effective dark mode preference.
39	66		// It takes the config value ("prefer-dark", "prefer-light", "default")
40	67		// and resolves "default" to the system preference.


@@ -2,6 +2,7 @@ package theme
2			2
3		import (	3		import (
4		"os"	4		"os"
			5	+	"os/exec"
5		"strings"	6		"strings"
6			7
7		"github.com/jwijenbergh/puregotk/v4/gtk"	8		"github.com/jwijenbergh/puregotk/v4/gtk"

@@ -10,7 +11,8 @@ import (
10		// DetectSystemDarkMode checks if the system prefers dark mode.	11		// DetectSystemDarkMode checks if the system prefers dark mode.
11		// It checks multiple sources in order of preference:	12		// It checks multiple sources in order of preference:
12		// 1. GTK_THEME environment variable (contains "dark")	13		// 1. GTK_THEME environment variable (contains "dark")
13	-	// 2. GTK Settings gtk-application-prefer-dark-theme property	14	+	// 2. GNOME gsettings color-scheme (prefer-dark/prefer-light)
			15	+	// 3. GTK Settings gtk-application-prefer-dark-theme property
14		// Returns true if dark mode is preferred.	16		// Returns true if dark mode is preferred.
15		func DetectSystemDarkMode() bool {	17		func DetectSystemDarkMode() bool {
16		// Check GTK_THEME environment variable first	18		// Check GTK_THEME environment variable first

@@ -23,6 +25,17 @@ func DetectSystemDarkMode() bool {
23		return false	25		return false
24		}	26		}
25			27
			28	+	// Check GNOME gsettings color-scheme (modern GNOME/GTK4 method)
			29	+	if colorScheme := getGsettingsColorScheme(); colorScheme != "" {
			30	+	switch colorScheme {
			31	+	case "prefer-dark":
			32	+	return true
			33	+	case "prefer-light":
			34	+	return false
			35	+	// "default" falls through to next check
			36	+	}
			37	+	}
			38	+
26		// Try GTK Settings	39		// Try GTK Settings
27		settings := gtk.SettingsGetDefault()	40		settings := gtk.SettingsGetDefault()
28		if settings != nil {	41		if settings != nil {

@@ -35,6 +48,20 @@ func DetectSystemDarkMode() bool {
35		return true	48		return true
36		}	49		}
37			50
			51	+	// getGsettingsColorScheme queries GNOME gsettings for the color-scheme preference.
			52	+	// Returns "prefer-dark", "prefer-light", "default", or empty string on error.
			53	+	func getGsettingsColorScheme() string {
			54	+	cmd := exec.Command("gsettings", "get", "org.gnome.desktop.interface", "color-scheme")
			55	+	output, err := cmd.Output()
			56	+	if err != nil {
			57	+	return ""
			58	+	}
			59	+	// Output is like "'prefer-dark'\n", strip quotes and whitespace
			60	+	result := strings.TrimSpace(string(output))
			61	+	result = strings.Trim(result, "'\"")
			62	+	return result
			63	+	}
			64	+
38		// ResolveColorScheme determines the effective dark mode preference.	65		// ResolveColorScheme determines the effective dark mode preference.
39		// It takes the config value ("prefer-dark", "prefer-light", "default")	66		// It takes the config value ("prefer-dark", "prefer-light", "default")
40		// and resolves "default" to the system preference.	67		// and resolves "default" to the system preference.