Add window transparency for linux (#1926)

v2/internal/frontend/desktop/linux/window.go

@@ -623,6 +623,17 @@ void SetWindowIcon(GtkWindow* window, const guchar* buf, gsize len) {
 	g_object_unref(loader);
 }
 
+static void SetWindowTransparency(GtkWidget *widget)
+{
+    GdkScreen *screen = gtk_widget_get_screen(widget);
+    GdkVisual *visual = gdk_screen_get_rgba_visual(screen);
+
+    if (visual != NULL && gdk_screen_is_composited(screen)) {
+		gtk_widget_set_app_paintable(widget, true);
+		gtk_widget_set_visual(widget, visual);
+    }
+}
+
 */
 import "C"
 import (
@@ -714,6 +725,9 @@ func NewWindow(appoptions *options.App, debug bool) *Window {
 		if appoptions.Linux.Icon != nil {
 			result.SetWindowIcon(appoptions.Linux.Icon)
 		}
+		if appoptions.Linux.WindowIsTranslucent {
+			C.SetWindowTransparency(gtkWindow)
+		}
 	}
 
 	// Menu

v2/pkg/options/linux/linux.go

@@ -2,5 +2,6 @@ package linux
 
 // Options specific to Linux builds
 type Options struct {
-	Icon []byte
+	Icon                []byte
+	WindowIsTranslucent bool
 }

website/docs/reference/options.mdx

@@ -89,6 +89,7 @@ func main() {
         },
         Linux: &linux.Options{
             Icon: icon,
+            WindowIsTranslucent: false,
         },
     })
     if err != nil {
@@ -748,3 +749,10 @@ On KDE it should work.
 
 The icon should be provided in whatever size it was naturally drawn; that is, don’t scale the image before passing it.
 Scaling is postponed until the last minute, when the desired final size is known, to allow best quality.
+
+#### WindowIsTranslucent
+
+Setting this to `true` will make the window background translucent. Some window managers may ignore it, or result in a black window.
+
+Name: WindowIsTranslucent<br/>
+Type: `bool`