From 415902fe832a525fe99c38b6afc925655c97ae5f Mon Sep 17 00:00:00 2001
From: Iain H <iain@spiralpoint.org>
Date: Mon, 23 Dec 2024 19:50:57 -0500
Subject: [PATCH] apprt/gtk: support dark window decorations with GtkWindow

Add support for the dark GtkWindow variant when `window-theme` is
`dark` or `auto`.
---
 src/apprt/gtk/App.zig | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/apprt/gtk/App.zig b/src/apprt/gtk/App.zig
index 8c42ddf37..042079dd6 100644
--- a/src/apprt/gtk/App.zig
+++ b/src/apprt/gtk/App.zig
@@ -221,6 +221,9 @@ pub fn init(core_app: *CoreApp, opts: Options) !App {
                 switch (config.@"window-theme") {
                     .system, .light => {},
                     .dark => {
+                        const settings = c.gtk_settings_get_default();
+                        c.g_object_set(@ptrCast(@alignCast(settings)), "gtk-application-prefer-dark-theme", true, @as([*c]const u8, null));
+
                         c.gtk_css_provider_load_from_resource(
                             provider,
                             "/com/mitchellh/ghostty/style-dark.css",
@@ -234,6 +237,9 @@ pub fn init(core_app: *CoreApp, opts: Options) !App {
                     .auto, .ghostty => {
                         const lum = config.background.toTerminalRGB().perceivedLuminance();
                         if (lum <= 0.5) {
+                            const settings = c.gtk_settings_get_default();
+                            c.g_object_set(@ptrCast(@alignCast(settings)), "gtk-application-prefer-dark-theme", true, @as([*c]const u8, null));
+
                             c.gtk_css_provider_load_from_resource(
                                 provider,
                                 "/com/mitchellh/ghostty/style-dark.css",