improv: Use Windows 10 style themes on Windows

Author: ids1024

.gitmodules

@@ -0,0 +1,6 @@
+[submodule "windows/themes/Windows-10-Dark"]
+	path = windows/themes/Windows-10-Dark
+	url = https://github.com/B00merang-Project/Windows-10-Dark
+[submodule "windows/themes/Windows-10"]
+	path = windows/themes/Windows-10
+	url = https://github.com/B00merang-Project/Windows-10

windows/build.py

@@ -83,6 +83,18 @@ def find_depends(exe):
     print(f"Copy {src} -> {dest}")
     shutil.copytree(src, dest)
 
+# Copy themes, and set default
+# Based on https://www.gtk.org/docs/installations/windows#building-and-distributing-your-application
+os.makedirs("out/share/themes/Windows10")
+os.makedirs("out/share/themes/Windows10-dark")
+os.makedirs("out/etc/gtk-3.0")
+print("Copy themes/Windows-10/gtk-3.20 -> out/share/themes/Windows10/gtk-3.0")
+shutil.copytree("themes/Windows-10/gtk-3.20", "out/share/themes/Windows10/gtk-3.0")
+print("Copy themes/Windows-10-dark/gtk-3.20 -> out/share/themes/Windows10-dark/gtk-3.0")
+shutil.copytree("themes/Windows-10-dark/gtk-3.20", "out/share/themes/Windows10-dark/gtk-3.0")
+with open("out/etc/gtk-3.0/settings.ini", "w") as f:
+    f.write("[Settings]\ngtk-theme-name=Windows10\ngtk-font-name=Segoe UI 9\n")
+
 # Extract crate version from cargo
 meta_str = subprocess.check_output(CARGO + ["metadata", "--format-version", "1", "--no-deps"])
 meta = json.loads(meta_str)