Add xcwm_window_get_opacity()

Signed-off-by: Jon TURNEY <jon.turney@dronecode.org.uk>

4 files changed, 47 insertions, 3 deletions

diff --git a/include/xcwm/window.h b/include/xcwm/window.h
index b510571..ad28790 100644
--- a/include/xcwm/window.h
+++ b/include/xcwm/window.h
@@ -104,6 +104,7 @@ struct xcwm_window_t {
     int override_redirect;
     int initial_damage;         /* Set to 1 for override-redirect windows */
     void *local_data;   /* Area for data client cares about */
+    unsigned int opacity;
 };
 
 /**
@@ -268,4 +269,12 @@ xcwm_window_iconify(xcwm_window_t *window);
 void
 xcwm_window_deiconify(xcwm_window_t *window);
 
+/**
+ * Get the opacity for the window.
+ * @param window The window to get opacity data for.
+ * @return The window opacity, in the range 0 (transparent) to 0xFFFFFFFF (opaque)
+ */
+unsigned int
+xcwm_window_get_opacity(xcwm_window_t const *window);
+
 #endif  /* _XCWM_WINDOW_H_ */
diff --git a/src/libxcwm/atoms.c b/src/libxcwm/atoms.c
index dac552a..45542dc 100644
--- a/src/libxcwm/atoms.c
+++ b/src/libxcwm/atoms.c
@@ -51,9 +51,12 @@ static void
 setup_window_type(xcwm_window_t *window);
 
 /* Get and set the size hints for the window */
-void
+static void
 set_window_size_hints(xcwm_window_t *window);
 
+/* Get opacity hint */
+static void
+set_window_opacity(xcwm_window_t *window);
 
 static xcb_atom_t
 _xcwm_atom_get(xcwm_context_t *context, const char *atomName)
@@ -137,12 +140,14 @@ _xcwm_atoms_init(xcwm_context_t *context)
     if (!check_wm_cm_owner(context)) {
         return XCB_WINDOW;
     }
+    create_wm_cm_window(context);
 
     /* WM_STATE atom */
     context->atoms->wm_state_atom = _xcwm_atom_get(context, "WM_STATE");
 
-    create_wm_cm_window(context);
-    
+    /* NET_WM_OPACITY */
+    context->atoms->wm_opacity_atom = _xcwm_atom_get(context, "_NET_WM_WINDOW_OPACITY");
+
     return 0;
 }
 
@@ -197,6 +202,7 @@ _xcwm_atoms_init_window(xcwm_window_t *window)
     _xcwm_atoms_set_wm_delete(window);
     setup_window_type(window);
     set_window_size_hints(window);
+    set_window_opacity(window);
 }
 
 
@@ -352,6 +358,27 @@ set_window_size_hints(xcwm_window_t *window)
 }
 
 void
+set_window_opacity(xcwm_window_t *window)
+{
+  xcb_get_property_cookie_t cookie;
+  cookie = xcb_get_property(window->context->conn, 0, window->window_id, window->context->atoms->wm_opacity_atom, XCB_ATOM_CARDINAL, 0L, 4L);
+
+  xcb_get_property_reply_t *reply = xcb_get_property_reply(window->context->conn, cookie, NULL);
+  if (reply)
+    {
+      int nitems = xcb_get_property_value_length(reply);
+      uint32_t *value = xcb_get_property_value(reply);
+
+      if (value && nitems == 4)
+        {
+          window->opacity = *value;
+        }
+
+      free(reply);
+    }
+}
+
+void
 _xcwm_atoms_set_wm_state(xcwm_window_t *window, xcwm_window_state_t state)
 {
     /* xcb_icccm_wm_state_t icccm_state; */
diff --git a/src/libxcwm/window.c b/src/libxcwm/window.c
index 7a2aaeb..eaa38ce 100644
--- a/src/libxcwm/window.c
+++ b/src/libxcwm/window.c
@@ -127,6 +127,7 @@ _xcwm_window_create(xcwm_context_t *context, xcb_window_t new_window,
     window->bounds->y = geom->y;
     window->bounds->width = geom->width;
     window->bounds->height = geom->height;
+    window->opacity = ~0;
 
     /* Find an set the parent */
     window->parent = _xcwm_get_window_node_by_window_id(parent);
@@ -368,6 +369,12 @@ xcwm_window_copy_name(xcwm_window_t const *window)
     return strdup(window->name);
 }
 
+unsigned int
+xcwm_window_get_opacity(xcwm_window_t const *window)
+{
+  return window->opacity;
+}
+
 xcwm_window_sizing_t const *
 xcwm_window_get_sizing(xcwm_window_t const *window)
 {
diff --git a/src/libxcwm/xcwm_internal.h b/src/libxcwm/xcwm_internal.h
index 11858f6..1a3716f 100644
--- a/src/libxcwm/xcwm_internal.h
+++ b/src/libxcwm/xcwm_internal.h
@@ -56,6 +56,7 @@ struct xcwm_wm_atoms_t {
     xcb_atom_t wm_name_atom;
     xcb_atom_t wm_state_atom;
     xcb_ewmh_connection_t ewmh_conn;
+    xcb_atom_t wm_opacity_atom;
 };
 
 /**