Composite systray with alpha channel and support stale systray windows without it. Add a beautiful.systray_skip_bg to skip background drawing, so it can blend nicely with other widgets.

awesome.c

@@ -809,6 +809,8 @@ main(int argc, char **argv)
         xcb_discard_reply(globalconf.connection,
                 xcb_damage_query_version(globalconf.connection, 1, 0).sequence);
 
+    globalconf.is_compositing = globalconf.have_composite && globalconf.have_damage;
+
     event_init();
 
     /* Allocate the key symbols */

common/atoms.list

@@ -57,6 +57,7 @@ ESETROOT_PMAP_ID
 WM_STATE
 _NET_WM_WINDOW_OPACITY
 _NET_SYSTEM_TRAY_ORIENTATION
+_NET_SYSTEM_TRAY_VISUAL
 WM_CHANGE_STATE
 WM_WINDOW_ROLE
 WM_CLIENT_LEADER

common/xembed.h

@@ -41,6 +41,7 @@ typedef struct xembed_window xembed_window_t;
 struct xembed_window
 {
     xcb_window_t win;
+    uint8_t depth;
     xembed_info_t info;
 };
 

event.c

@@ -1026,6 +1026,10 @@ event_handle_selectionclear(xcb_selection_clear_event_t *ev)
 
 static void
 event_handle_damage_notify(xcb_damage_notify_event_t *ev) {
+    if (ev->drawable == globalconf.systray.window) {
+        luaA_systray_invalidate();
+        xcb_damage_subtract(globalconf.connection, ev->damage, None, None);
+    }
 }
 
 /** \brief awesome xerror function.

globalconf.h

@@ -130,6 +130,8 @@ typedef struct
     bool have_composite;
     /** Check for Damage extenion */
     bool have_damage;
+    /** Enable compositing features? */
+    bool is_compositing;
     /** Custom searchpaths are present, the runtime is tinted */
     bool have_searchpaths;
     /** When --no-argb is used in the modeline or command line */

lib/wibox/widget/systray.lua

@@ -7,7 +7,9 @@
 
 local wbase = require("wibox.widget.base")
 local drawable = require("wibox.drawable")
+local cairo = require("lgi").cairo
 local beautiful = require("beautiful")
+local gcolor = require("gears.color")
 local gtable = require("gears.table")
 local capi = {
     awesome = awesome,
@@ -42,6 +44,11 @@ local display_on_screen = "primary"
 -- @beautiful beautiful.systray_icon_spacing
 -- @tparam[opt=0] integer The icon spacing
 
+--- Whether to skip drawing the systray background when compositing the systray icons.
+--
+-- @beautiful beautiful.systray_skip_bg
+-- @tparam[opt=0] boolean Whether to skip drawing the systray background
+
 local function should_display_on(s)
     if display_on_screen == "primary" then
         return s == capi.screen.primary
@@ -90,6 +97,23 @@ function systray:draw(context, cr, width, height)
     end
     capi.awesome.systray(context.wibox.drawin, math.ceil(x), math.ceil(y),
                          base, is_rotated, bg, reverse, spacing, rows)
+
+    local surf_width, surf_height =
+        base * rows + spacing * (rows - 1),
+        base * cols + spacing * (cols - 1)
+    if is_rotated then
+        surf_width, surf_height = surf_height, surf_width
+    end
+    local surf_raw = capi.awesome.systray_surface(surf_width, surf_height)
+    if surf_raw then
+        local surf = cairo.Surface(surf_raw, true)
+        if not beautiful.systray_skip_bg then
+            cr:set_source(gcolor(bg))
+            cr:paint()
+        end
+        cr:set_source_surface(surf, 0, 0)
+        cr:paint()
+    end
 end
 
 -- Private API. Does not appear in LDoc on purpose. This function is called

luaa.c

@@ -1090,6 +1090,7 @@ luaA_init(xdgHandle* xdg, string_array_t *searchpath)
         { "disconnect_signal", luaA_awesome_disconnect_signal },
         { "emit_signal", luaA_awesome_emit_signal },
         { "systray", luaA_systray },
+        { "systray_surface", luaA_systray_surface },
         { "load_image", luaA_load_image },
         { "pixbuf_to_surface", luaA_pixbuf_to_surface },
         { "set_preferred_icon_size", luaA_set_preferred_icon_size },

objects/drawin.c

@@ -45,6 +45,7 @@
 
 #include <cairo-xcb.h>
 #include <xcb/shape.h>
+#include <xcb/composite.h>
 
 lua_class_t drawin_class;
 
@@ -451,6 +452,8 @@ drawin_allocator(lua_State *L)
                           globalconf.default_cmap,
                           xcursor_new(globalconf.cursor_ctx, xcursor_font_fromstr(w->cursor))
                       });
+    if (globalconf.is_compositing)
+        xcb_composite_redirect_subwindows(globalconf.connection, w->window, XCB_COMPOSITE_REDIRECT_MANUAL);
     xwindow_set_class_instance(w->window);
     xwindow_set_name_static(w->window, "Awesome drawin");
 

spec/wibox/widget/systray_spec.lua

@@ -27,7 +27,10 @@ _G.awesome = {
             systray_arguments = { first_arg, ... }
         end
         return num_systray_icons
-    end
+    end,
+    systray_surface = function()
+        return nil
+    end,
 }
 _G.screen = {
     connect_signal = function() end

systray.c

@@ -29,6 +29,8 @@
 #include <xcb/xcb.h>
 #include <xcb/xcb_icccm.h>
 #include <xcb/xcb_atom.h>
+#include <xcb/damage.h>
+#include <cairo-xcb.h>
 
 #define SYSTEM_TRAY_REQUEST_DOCK 0 /* Begin icon docking */
 
@@ -44,6 +46,21 @@ systray_init(void)
 
     globalconf.systray.window = xcb_generate_id(globalconf.connection);
     globalconf.systray.background_pixel = xscreen->black_pixel;
+    if (globalconf.is_compositing) {
+        xcb_create_window(globalconf.connection, globalconf.default_depth,
+                          globalconf.systray.window,
+                          xscreen->root,
+                          -1, -1, 1, 1, 0,
+                          XCB_COPY_FROM_PARENT, globalconf.visual->visual_id,
+                          XCB_CW_BACK_PIXEL | XCB_CW_BORDER_PIXEL | XCB_CW_EVENT_MASK | XCB_CW_COLORMAP,
+                          (const uint32_t [])
+                          { xscreen->black_pixel, xscreen->black_pixel, XCB_EVENT_MASK_SUBSTRUCTURE_REDIRECT, globalconf.default_cmap });
+        xcb_damage_create(globalconf.connection, xcb_generate_id(globalconf.connection), globalconf.systray.window, XCB_DAMAGE_REPORT_LEVEL_NON_EMPTY);
+        xcb_change_property(globalconf.connection, XCB_PROP_MODE_REPLACE,
+                            globalconf.systray.window, _NET_SYSTEM_TRAY_VISUAL,
+                            XCB_ATOM_VISUALID, 32, 1, (const uint32_t [])
+                            { globalconf.visual->visual_id });
+    } else {
         xcb_create_window(globalconf.connection, xscreen->root_depth,
                           globalconf.systray.window,
                           xscreen->root,
@@ -51,6 +68,7 @@ systray_init(void)
                           XCB_COPY_FROM_PARENT, xscreen->root_visual,
                           XCB_CW_BACK_PIXEL | XCB_CW_EVENT_MASK, (const uint32_t [])
                           { xscreen->black_pixel, XCB_EVENT_MASK_SUBSTRUCTURE_REDIRECT });
+    }
     xwindow_set_class_instance(globalconf.systray.window);
     xwindow_set_name_static(globalconf.systray.window, "Awesome systray window");
 
@@ -130,6 +148,8 @@ int
 systray_request_handle(xcb_window_t embed_win)
 {
     xembed_window_t em;
+    xcb_get_geometry_cookie_t geom_c;
+    xcb_get_geometry_reply_t *geom_r;
     xcb_get_property_cookie_t em_cookie;
     const uint32_t select_input_val[] =
     {
@@ -142,6 +162,12 @@ systray_request_handle(xcb_window_t embed_win)
     if(xembed_getbywin(&globalconf.embedded, embed_win))
         return -1;
 
+    geom_c = xcb_get_geometry(globalconf.connection, embed_win);
+    if(!(geom_r = xcb_get_geometry_reply(globalconf.connection, geom_c, NULL)))
+        return -1;
+    em.depth = geom_r->depth;
+    p_delete(&geom_r);
+
     p_clear(&em_cookie, 1);
 
     em_cookie = xembed_info_get_unchecked(globalconf.connection, embed_win);
@@ -149,6 +175,15 @@ systray_request_handle(xcb_window_t embed_win)
     xcb_change_window_attributes(globalconf.connection, embed_win, XCB_CW_EVENT_MASK,
                                  select_input_val);
 
+
+    if (globalconf.is_compositing && em.depth != globalconf.default_depth) {
+        /* Disable the message because the test runner is not happy with warnings. This should rarely happen anyway. */
+        /* warn("Fixing the background of the systray window 0x%x possibly because the client does not support composition.", embed_win); */
+        xcb_change_window_attributes(globalconf.connection, embed_win, XCB_CW_BACK_PIXEL,
+                                     (const uint32_t []){ globalconf.systray.background_pixel });
+        xcb_clear_area(globalconf.connection, 1, embed_win, 0, 0, 0, 0);
+    }
+
     /* we grab the window, but also make sure it's automatically reparented back
      * to the root window if we should die.
      */
@@ -376,6 +411,14 @@ luaA_systray(lua_State *L)
                 && globalconf.systray.background_pixel != bg_color.pixel)
         {
             uint32_t config_back[] = { bg_color.pixel };
+            if (globalconf.is_compositing) {
+                foreach(em, globalconf.embedded)
+                    if (em->depth != globalconf.default_depth) {
+                        xcb_change_window_attributes(
+                            globalconf.connection, em->win, XCB_CW_BACK_PIXEL, config_back);
+                        xcb_clear_area(globalconf.connection, 1, em->win, 0, 0, 0, 0);
+                    }
+            } else {
                 globalconf.systray.background_pixel = bg_color.pixel;
                 xcb_change_window_attributes(globalconf.connection,
                                              globalconf.systray.window,
@@ -383,6 +426,7 @@ luaA_systray(lua_State *L)
                 xcb_clear_area(globalconf.connection, 1, globalconf.systray.window, 0, 0, 0, 0);
                 force_redraw = true;
             }
+        }
 
         if(globalconf.systray.parent != w)
             xcb_reparent_window(globalconf.connection,
@@ -413,4 +457,29 @@ luaA_systray(lua_State *L)
     return 2;
 }
 
+/** Return the native surface of the systray if composite is enabled.
+ * \param L The Lua VM state.
+ * \return the number of element returned. (1)
+  * \luastack
+ * \lparam width The width of the systray surface.
+ * \lparam height The height of the systray surface.
+ */
+int
+luaA_systray_surface(lua_State *L)
+{
+    if (!globalconf.is_compositing) {
+        lua_pushnil(L);
+        return 1;
+    }
+
+    int width = luaL_checkinteger(L, 1);
+    int height = luaL_checkinteger(L, 2);
+    /* Lua has to make sure to free the ref or we have a leak */
+    lua_pushlightuserdata(
+        L, cairo_xcb_surface_create(
+            globalconf.connection, globalconf.systray.window, globalconf.visual,
+            width, height));
+    return 1;
+}
+
 // vim: filetype=c:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:textwidth=80

systray.h

@@ -33,6 +33,7 @@ bool systray_iskdedockapp(xcb_window_t);
 int systray_process_client_message(xcb_client_message_event_t *);
 int xembed_process_client_message(xcb_client_message_event_t *);
 int luaA_systray(lua_State *);
+int luaA_systray_surface(lua_State *);
 
 #endif
 // vim: filetype=c:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:textwidth=80

tests/test-systray.c

@@ -65,8 +65,8 @@ static xcb_window_t find_systray(xcb_connection_t *conn, xcb_atom_t net_system_t
     return owner;
 }
 
-static uint32_t get_color(xcb_connection_t *conn, xcb_screen_t *screen, uint16_t red, uint16_t green, uint16_t blue) {
+static uint32_t get_color(xcb_connection_t *conn, xcb_colormap_t cm, uint16_t red, uint16_t green, uint16_t blue) {
-    xcb_alloc_color_reply_t *reply = xcb_alloc_color_reply(conn, xcb_alloc_color(conn, screen->default_colormap, red, green, blue), NULL);
+    xcb_alloc_color_reply_t *reply = xcb_alloc_color_reply(conn, xcb_alloc_color(conn, cm, red, green, blue), NULL);
     if (!reply)
         fatal("Error allocating color");
     uint32_t pixel = reply->pixel;
@@ -74,6 +74,19 @@ static uint32_t get_color(xcb_connection_t *conn, xcb_screen_t *screen, uint16_t
     return pixel;
 }
 
+static uint8_t find_visual_depth(const xcb_screen_t *s, xcb_visualid_t visual)
+{
+    xcb_depth_iterator_t depth_iter = xcb_screen_allowed_depths_iterator(s);
+
+    if(depth_iter.data)
+        for(; depth_iter.rem; xcb_depth_next (&depth_iter))
+            for(xcb_visualtype_iterator_t visual_iter = xcb_depth_visuals_iterator(depth_iter.data);
+                visual_iter.rem; xcb_visualtype_next (&visual_iter))
+                if(visual == visual_iter.data->visual_id)
+                    return depth_iter.data->depth;
+    return 0;
+}
+
 int main() {
     int default_screen;
     xcb_connection_t* conn = xcb_connect(NULL, &default_screen);
@@ -82,15 +95,54 @@ int main() {
     }
     atoms_init(conn);
     xcb_screen_t* screen = xcb_aux_get_screen(conn, default_screen);
+    xcb_window_t systray_owner = find_systray(conn, systray_atom(conn, default_screen));
+
+    // Try to use tray visual hint, if requested.
+    char *use_hint_var = getenv("USE_TRAY_VISUAL_HINT");
+    bool use_tray_visual_hint = use_hint_var && *use_hint_var;
+    xcb_visualid_t tray_visual_id;
+    uint8_t tray_depth;
+    if (use_tray_visual_hint) {
+        xcb_get_property_reply_t *tray_visual_r =
+            xcb_get_property_reply(
+                conn, xcb_get_property(conn, false, systray_owner,
+                                       _NET_SYSTEM_TRAY_VISUAL,
+                                       XCB_ATOM_VISUALID, 0, 1),
+                NULL);
+        tray_visual_id = screen->root_visual;
+        if(tray_visual_r != NULL && xcb_get_property_value_length(tray_visual_r)) {
+            tray_visual_id = *(uint32_t *)xcb_get_property_value(tray_visual_r);
+            p_delete(&tray_visual_r);
+        }
+        tray_depth = find_visual_depth(screen, tray_visual_id);
+        if (tray_depth == 0) {
+            fatal("Error getting visual hint\n");
+        }
+    } else {
+        tray_visual_id= screen->root_visual;
+        tray_depth = screen->root_depth;
+    }
+
+    xcb_colormap_t cm = xcb_generate_id(conn);
+    xcb_create_colormap(conn, XCB_COLORMAP_ALLOC_NONE,
+                        cm, screen->root,
+                        tray_visual_id);
 
     // Create a window for the systray icon
     xcb_window_t window = xcb_generate_id(conn);
-    xcb_create_window(conn, screen->root_depth, window, screen->root, 0, 0, 10, 10, 0, XCB_WINDOW_CLASS_INPUT_OUTPUT,
+    xcb_create_window(conn, tray_depth, window, screen->root, 0, 0, 10, 10, 0, XCB_WINDOW_CLASS_INPUT_OUTPUT,
-            screen->root_visual, XCB_CW_BACK_PIXEL, (uint32_t[]) { get_color(conn, screen, 0xffff, 0x9999, 0x0000) });
+                      tray_visual_id,
+                      (use_tray_visual_hint ? XCB_CW_BACK_PIXEL : XCB_CW_BACK_PIXMAP)
+                          | XCB_CW_BORDER_PIXEL | XCB_CW_COLORMAP,
+                      (uint32_t[]) {
+                          use_tray_visual_hint
+                              ? get_color(conn, cm, 0xffff, 0x9999, 0x0000)
+                              : XCB_BACK_PIXMAP_PARENT_RELATIVE,
+                          screen->black_pixel, cm
+                      });
     xcb_change_property(conn, XCB_PROP_MODE_REPLACE, window, _XEMBED_INFO, _XEMBED_INFO, 32, 2, (uint32_t[]) { 0, 1 });
 
     // Make our window a systray icon
-    xcb_window_t systray_owner = find_systray(conn, systray_atom(conn, default_screen));
     xcb_client_message_event_t ev;
 
     p_clear(&ev, 1);

tests/test-systray.lua

@@ -2,7 +2,7 @@ local spawn = require("awful.spawn")
 local wibox = require("wibox")
 local beautiful = require("beautiful")
 
-local steps, pid1, pid2, draw_w, st = {}
+local steps, pid1, pid2, draw_w, wb, st = {}
 
 table.insert(steps, function()
     screen[1].mywibox:remove()
@@ -17,7 +17,7 @@ table.insert(steps, function()
         draw_w = width
     end
 
-    local wb = wibox {
+    wb = wibox {
         x       = 0,
         y       = 0,
         width   = 100,
@@ -81,6 +81,58 @@ table.insert(steps, function()
     return true
 end)
 
+table.insert(steps, function()
+    if draw_w ~= 100 then return end
+    return true
+end)
+
+table.insert(steps, function()
+    st.base_size = 20
+    pid1 = spawn("env USE_TRAY_VISUAL_HINT=1 ./test-systray")
+    return true
+end)
+
+local lgi_core = require("lgi.core")
+local lgi_ffi = require("lgi.ffi")
+local lgi_ti = lgi_ffi.types
+local lgi_record = require("lgi.record")
+local lgi_component = require("lgi.component")
+local cairo = require("lgi").cairo
+local wrapped_uchar = lgi_component.create(nil, lgi_record.struct_mt, "wrapped_uchar")
+lgi_ffi.load_fields(wrapped_uchar, { { 'v', lgi_ti.uchar } })
+
+table.insert(steps, function()
+    if draw_w ~= 80 then return end
+    local systray_surface_raw = awesome.systray_surface(20, 20)
+    if systray_surface_raw then
+        local src = cairo.Surface(systray_surface_raw, true)
+        local s = cairo.ImageSurface("ARGB32", 20, 20)
+        local cr = cairo.Context(s)
+        cr:set_source_surface(src, 0, 0)
+        cr:paint()
+        -- Read the first pixel (a,r,g,b) as 4 8-bit integers.
+        local data = s:get_data()
+        local array = lgi_core.record.new(wrapped_uchar, data, false)
+        local argb = {}
+        for i = 0, 3 do
+            argb[i + 1] = lgi_core.record.fromarray(array, i).v
+        end
+        -- Check with the pixel from test-systray.c
+        return
+            argb[1] == 0 and
+            argb[2] == 153 and
+            argb[3] == 255 and
+            argb[4] == 255
+    else
+        print("Systray composition test is disabled.")
+        return true
+    end
+end)
+
+table.insert(steps, function()
+    awesome.kill(pid1, 9)
+    return true
+end)
 
 table.insert(steps, function()
     if draw_w ~= 100 then return end