4 files changed, 78 insertions, 9 deletions

diff --git a/include/cru/platform/gui/xcb/UiApplication.h b/include/cru/platform/gui/xcb/UiApplication.h
index 2a9ea517..87fd1063 100644
--- a/include/cru/platform/gui/xcb/UiApplication.h
+++ b/include/cru/platform/gui/xcb/UiApplication.h
@@ -7,6 +7,8 @@
 
 #include <xcb/xcb.h>
 #include <functional>
+#include <string>
+#include <unordered_map>
 
 namespace cru::platform::gui::xcb {
 class XcbWindow;
@@ -28,6 +30,11 @@ class XcbUiApplication : public XcbResource, public virtual IUiApplication {
   // This API is weird, but before we have correct screen API, we still use it.
   xcb_screen_t* GetFirstXcbScreen();
 
+  xcb_atom_t GetOrCreateXcbAtom(std::string name);
+  xcb_atom_t GetXcbAtom_NET_WM_WINDOW_TYPE();
+  xcb_atom_t GetXcbAtom_NET_WM_WINDOW_TYPE_NORMAL();
+  xcb_atom_t GetXcbAtom_NET_WM_WINDOW_TYPE_UTILITY();
+
  public:
   int Run() override;
 
@@ -81,6 +88,7 @@ class XcbUiApplication : public XcbResource, public virtual IUiApplication {
 
   xcb_connection_t* xcb_connection_;
   xcb_screen_t* screen_;
+  std::unordered_map<std::string, xcb_atom_t> xcb_atom_;
 
   cru::platform::unix::UnixEventLoop event_loop_;
   std::vector<std::function<void()>> quit_handlers_;
diff --git a/include/cru/platform/gui/xcb/Window.h b/include/cru/platform/gui/xcb/Window.h
index f9fbf735..43cd3b53 100644
--- a/include/cru/platform/gui/xcb/Window.h
+++ b/include/cru/platform/gui/xcb/Window.h
@@ -23,8 +23,8 @@ class XcbWindow : public XcbResource, public virtual INativeWindow {
   INativeWindow* GetParent() override;
   void SetParent(INativeWindow* parent) override;
 
-  virtual WindowStyleFlag GetStyleFlag() = 0;
-  virtual void SetStyleFlag(WindowStyleFlag flag) = 0;
+  WindowStyleFlag GetStyleFlag() override;
+  void SetStyleFlag(WindowStyleFlag flag) override;
 
   virtual String GetTitle() = 0;
   virtual void SetTitle(String title) = 0;
@@ -88,11 +88,15 @@ class XcbWindow : public XcbResource, public virtual INativeWindow {
   void HandleEvent(xcb_generic_event_t* event);
   static std::optional<xcb_window_t> GetEventWindow(xcb_generic_event_t* event);
 
+  void DoSetParent(xcb_window_t window);
+  void DoSetStyleFlags(xcb_window_t window);
+
  private:
   XcbUiApplication* application_;
   std::optional<xcb_window_t> xcb_window_;
   cairo_surface_t* cairo_surface_;
   Size current_size_;
+  WindowStyleFlag style_;
 
   XcbWindow* parent_;
 
diff --git a/src/platform/gui/xcb/UiApplication.cpp b/src/platform/gui/xcb/UiApplication.cpp
index 462e2fde..2fceac30 100644
--- a/src/platform/gui/xcb/UiApplication.cpp
+++ b/src/platform/gui/xcb/UiApplication.cpp
@@ -49,6 +49,32 @@ xcb_connection_t *XcbUiApplication::GetXcbConnection() {
 
 xcb_screen_t *XcbUiApplication::GetFirstXcbScreen() { return screen_; }
 
+xcb_atom_t XcbUiApplication::GetOrCreateXcbAtom(std::string name) {
+  auto iter = xcb_atom_.find(name);
+  if (iter != xcb_atom_.cend()) {
+    return iter->second;
+  }
+
+  auto cookie =
+      xcb_intern_atom(xcb_connection_, false, name.size(), name.data());
+  auto reply = xcb_intern_atom_reply(xcb_connection_, cookie, nullptr);
+  auto atom = reply->atom;
+  xcb_atom_.emplace(std::move(name), atom);
+  return atom;
+}
+
+xcb_atom_t XcbUiApplication::GetXcbAtom_NET_WM_WINDOW_TYPE() {
+  return GetOrCreateXcbAtom("_NET_WM_WINDOW_TYPE");
+}
+
+xcb_atom_t XcbUiApplication::GetXcbAtom_NET_WM_WINDOW_TYPE_NORMAL() {
+  return GetOrCreateXcbAtom("_NET_WM_WINDOW_TYPE_NORMAL");
+}
+
+xcb_atom_t XcbUiApplication::GetXcbAtom_NET_WM_WINDOW_TYPE_UTILITY() {
+  return GetOrCreateXcbAtom("_NET_WM_WINDOW_TYPE_UTILITY");
+}
+
 int XcbUiApplication::Run() {
   auto exit_code = event_loop_.Run();
 
diff --git a/src/platform/gui/xcb/Window.cpp b/src/platform/gui/xcb/Window.cpp
index 9dd510e9..9b72789b 100644
--- a/src/platform/gui/xcb/Window.cpp
+++ b/src/platform/gui/xcb/Window.cpp
@@ -76,13 +76,16 @@ INativeWindow *XcbWindow::GetParent() { return parent_; }
 void XcbWindow::SetParent(INativeWindow *parent) {
   parent_ = CheckPlatform<XcbWindow>(parent, GetPlatformIdUtf8());
   if (xcb_window_) {
-    auto real_parent = application_->GetFirstXcbScreen()->root;
-    if (parent_ && parent_->xcb_window_) {
-      real_parent = *parent_->xcb_window_;
-    }
-    xcb_reparent_window(application_->GetXcbConnection(), *xcb_window_,
-                        real_parent, 0, 0);
-    // TODO: Maybe restore position?
+    DoSetParent(*xcb_window_);
+  }
+}
+
+WindowStyleFlag XcbWindow::GetStyleFlag() { return style_; }
+
+void XcbWindow::SetStyleFlag(WindowStyleFlag flag) {
+  style_ = flag;
+  if (xcb_window_) {
+    DoSetStyleFlags(*xcb_window_);
   }
 }
 
@@ -160,6 +163,9 @@ xcb_window_t XcbWindow::DoCreateWindow() {
                     screen->root_visual, mask, values);
   current_size_ = Size(width, height);
 
+  DoSetStyleFlags(window);
+  DoSetParent(window);
+
   xcb_visualtype_t *visual_type;
 
   for (xcb_depth_iterator_t depth_iter =
@@ -361,4 +367,29 @@ std::optional<xcb_window_t> XcbWindow::GetEventWindow(
       return std::nullopt;
   }
 }
+
+void XcbWindow::DoSetParent(xcb_window_t window) {
+  auto real_parent =
+      application_->GetFirstXcbScreen()->root;  // init to desktop
+  if (parent_ && parent_->xcb_window_) {
+    real_parent = *parent_->xcb_window_;
+  }
+  xcb_reparent_window(application_->GetXcbConnection(), window, real_parent, 0,
+                      0);
+  // TODO: Maybe restore position?
+}
+
+void XcbWindow::DoSetStyleFlags(xcb_window_t window) {
+  std::vector<xcb_atom_t> atoms;
+  if (style_.Has(WindowStyleFlags::NoCaptionAndBorder)) {
+    atoms = {application_->GetXcbAtom_NET_WM_WINDOW_TYPE_UTILITY()};
+  } else {
+    atoms = {application_->GetXcbAtom_NET_WM_WINDOW_TYPE_NORMAL()};
+  }
+
+  xcb_change_property(application_->GetXcbConnection(), XCB_PROP_MODE_REPLACE,
+                      window, application_->GetXcbAtom_NET_WM_WINDOW_TYPE(),
+                      XCB_ATOM_ATOM, 32, atoms.size(), atoms.data());
+}
+
 }  // namespace cru::platform::gui::xcb