fix(tray): fix transparency after background manager changes

The systray only supports pseudo transparency (real transparency would require
much larger changes) so the real transparency should only be used for the bar itself.

include/components/renderer.hpp

@@ -120,6 +120,7 @@ class renderer
   cairo_operator_t m_comp_ol{CAIRO_OPERATOR_OVER};
   cairo_operator_t m_comp_ul{CAIRO_OPERATOR_OVER};
   cairo_operator_t m_comp_border{CAIRO_OPERATOR_OVER};
+  bool m_pseudo_transparency{false};
 
   alignment m_align;
   std::bitset<3> m_attr;

include/x11/background_manager.hpp

@@ -47,11 +47,9 @@ class background_manager : public signal_receiver<SIGN_PRIORITY_SCREEN, signals:
   unique_ptr<cairo::xcb_surface> m_surface;
 
   bool m_attached{false};
-  bool m_pseudo_transparency{false};
 
-  void allocate_resources(bool use_root_depth);
+  void allocate_resources();
   void free_resources();
-  void make_transparent_pixmap();
   void fetch_root_pixmap();
 
 };

src/components/renderer.cpp

@@ -175,6 +175,8 @@ renderer::renderer(
   m_comp_ul = m_conf.get<cairo_operator_t>("settings", "compositing-underline", m_comp_ul);
   m_comp_border = m_conf.get<cairo_operator_t>("settings", "compositing-border", m_comp_border);
 
+  m_pseudo_transparency = m_conf.get<bool>("settings", "pseudo-transparency", m_pseudo_transparency);
+
   m_fixedcenter = m_conf.get(m_conf.section(), "fixed-center", true);
 }
 
@@ -503,14 +505,21 @@ void renderer::fill_background() {
   m_context->save();
   *m_context << m_comp_bg;
 
-  auto root_bg = m_background.get_surface();
-  if(root_bg != nullptr) {
-    m_log.trace_x("renderer: root background");
-    *m_context << *root_bg;
-    m_context->paint();
-    *m_context << CAIRO_OPERATOR_OVER;
+  // if using pseudo-transparency, fill the background with the root window's contents
+  // otherwise, we simply use a fully transparent base layer
+  if(m_pseudo_transparency) {
+    auto root_bg = m_background.get_surface();
+    if(root_bg != nullptr) {
+      m_log.trace_x("renderer: root background");
+      *m_context << *root_bg;
+    }
+  } else {
+    *m_context << (unsigned int)0;
   }
 
+  m_context->paint();
+  *m_context << CAIRO_OPERATOR_OVER;
+
   if (!m_bar.background_steps.empty()) {
     m_log.trace_x("renderer: gradient background (steps=%lu)", m_bar.background_steps.size());
     *m_context << cairo::linear_gradient{0.0, 0.0 + m_rect.y, 0.0, 0.0 + m_rect.height, m_bar.background_steps};

src/x11/background_manager.cpp

@@ -21,7 +21,6 @@ background_manager::background_manager(
   , m_sig(sig)
   , m_log(log) {
   m_sig.attach(this);
-  m_pseudo_transparency = config::make().get("settings", "pseudo-transparency", false);
 }
 
 background_manager::~background_manager() {
@@ -43,7 +42,7 @@ void background_manager::activate(xcb_window_t window, xcb_rectangle_t rect) {
   free_resources();
 
   // make sure that we receive a notification when the background changes
-  if(!m_attached && m_pseudo_transparency) {
+  if(!m_attached) {
     m_connection.ensure_event_mask(m_connection.root(), XCB_EVENT_MASK_PROPERTY_CHANGE);
     m_connection.flush();
     m_connection.attach_sink(this, SINK_PRIORITY_SCREEN);
@@ -51,11 +50,7 @@ void background_manager::activate(xcb_window_t window, xcb_rectangle_t rect) {
 
   m_window = window;
   m_rect = rect;
-  if(m_pseudo_transparency) {
-    fetch_root_pixmap();
-  } else {
-    make_transparent_pixmap();
-  }
+  fetch_root_pixmap();
 }
 
 void background_manager::deactivate() {
@@ -63,7 +58,7 @@ void background_manager::deactivate() {
 }
 
 
-void background_manager::allocate_resources(bool use_root_depth) {
+void background_manager::allocate_resources() {
   if(!m_visual) {
     m_log.trace("background_manager: Finding root visual");
     m_visual = m_connection.visual_type_for_id(m_connection.screen(), m_connection.screen()->root_visual);
@@ -73,8 +68,7 @@ void background_manager::allocate_resources(bool use_root_depth) {
   if(m_pixmap == XCB_NONE) {
     m_log.trace("background_manager: Allocating pixmap");
     m_pixmap = m_connection.generate_id();
-    auto depth = use_root_depth ? m_connection.screen()->root_depth : 32;
-    m_connection.create_pixmap(depth, m_pixmap, m_window, m_rect.width, m_rect.height);
+    m_connection.create_pixmap(m_connection.screen()->root_depth, m_pixmap, m_window, m_rect.width, m_rect.height);
   }
 
   if(m_gcontext == XCB_NONE) {
@@ -112,16 +106,8 @@ void background_manager::free_resources() {
   }
 }
 
-void background_manager::make_transparent_pixmap() {
-  allocate_resources(false);
-
-  m_log.trace("background_manager: Using transparent background pixmap");
-  auto context = cairo::context(*m_surface, m_log);
-  context << (unsigned int)0;
-}
-
 void background_manager::fetch_root_pixmap() {
-  allocate_resources(true);
+  allocate_resources();
 
   m_log.trace("background_manager: Fetching pixmap");
 
@@ -152,8 +138,6 @@ void background_manager::fetch_root_pixmap() {
 }
 
 void background_manager::handle(const evt::property_notify& evt) {
-  if(!m_pseudo_transparency) return;
-
   // if region that we should observe is empty, don't do anything
   if(m_rect.width == 0 || m_rect.height == 0) return;
 
@@ -164,8 +148,6 @@ void background_manager::handle(const evt::property_notify& evt) {
 }
 
 bool background_manager::on(const signals::ui::update_geometry&) {
-  if(!m_pseudo_transparency) return false;
-
   fetch_root_pixmap();
   m_sig.emit(signals::ui::update_background());
   return false;