add random, broken hack to get the basics of damage reporting in

3 files changed, 154 insertions, 50 deletions

diff --git a/Makefile b/Makefile
index c57528f..a2d8a44 100644
--- a/Makefile
+++ b/Makefile
@@ -1,3 +1,3 @@
 all:
-	gcc pop-overlay-window.c pop-window.c pop-demo.c -o pop-demo `pkg-config --cflags --libs glib-2.0 gtk+-2.0 cairo cairo-xlib` -lXcomposite -ggdb3 -O0
+	gcc pop-overlay-window.c pop-window.c pop-demo.c -o pop-demo `pkg-config --cflags --libs glib-2.0 gtk+-2.0 cairo cairo-xlib xcomposite xdamage ` -ggdb3 -O0
 
diff --git a/pop-demo.c b/pop-demo.c
index 57edea4..8224abf 100644
--- a/pop-demo.c
+++ b/pop-demo.c
@@ -3,6 +3,7 @@
 #include <glib.h>
 
 #include <X11/extensions/Xcomposite.h>
+#include <X11/extensions/Xdamage.h>
 #include <X11/extensions/Xfixes.h>
 
 #include <cairo.h>
@@ -15,9 +16,12 @@
 #include "pop-overlay-window.h"
 #include "pop-window.h"
 
-static GList *window_list = NULL;
+static GList *window_list = NULL, *pending_window_redraw_list = NULL;;
 
-gboolean
+static int damage_extension_event_base,
+           damage_extension_error_base;
+
+static gboolean
 composite_is_available (void)
 {
   int event_base, error_base;
@@ -25,7 +29,17 @@ composite_is_available (void)
   event_base = 0;
   error_base = 0;
   if (XCompositeQueryExtension (GDK_DISPLAY (), &event_base, &error_base))
-          return TRUE;
+    return TRUE;
+  return FALSE;
+}
+
+static gboolean
+initialize_damage_extension (void)
+{
+  if (XDamageQueryExtension (GDK_DISPLAY (), &damage_extension_event_base, 
+                             &damage_extension_error_base))
+      return TRUE;
+
   return FALSE;
 }
 
@@ -34,8 +48,12 @@ draw_windows (cairo_t *cairo_context)
 {
   GList *tmp;
 
-  for (tmp = window_list; tmp != NULL; tmp = tmp->next)
+  for (tmp = pending_window_redraw_list; tmp != NULL; tmp = tmp->next)
     pop_window_draw (POP_WINDOW (tmp->data), cairo_context);
+
+  g_list_foreach (pending_window_redraw_list, (GFunc) g_object_unref, NULL);
+  g_list_free (pending_window_redraw_list);
+  pending_window_redraw_list = NULL;
 }
 
 static void
@@ -46,27 +64,53 @@ free_window_list (void)
   window_list = NULL;
 }
 
+gint
+window_compare (PopWindow *window_1, 
+                Window    *x_window_id)
+{
+   return ((gulong ) pop_window_get_x_window_id (window_1)) 
+          - *x_window_id;
+}
+
+static PopWindow *
+find_window_from_x_window_id (Window x_window_id)
+{
+   
+    GList *node;
+
+    node = g_list_find_custom (window_list, &x_window_id,
+                               (GCompareFunc) window_compare);
+
+    if (node == NULL)
+      return NULL;
+
+    return (PopWindow *) node->data;
+}
+
 static void
-create_window_list (void)
+refresh_window_list (void)
 {
   Window root, parent;
-  Window *windows;
+  Window *x_window_ids;
   guint number_of_windows, i;
 
   if (!XQueryTree (GDK_DISPLAY (),
                    GDK_ROOT_WINDOW (), &root, &parent,
-                   &windows, &number_of_windows))
+                   &x_window_ids, &number_of_windows))
     return;
 
   for (i = 0; i < number_of_windows; i++) 
     {
-      PopWindow *window;
-      
-      window = pop_window_new (windows[i]);
-      window_list = g_list_append (window_list, window);
+      if (!find_window_from_x_window_id (x_window_ids[i]))
+        {
+          PopWindow *window;
+
+          window = pop_window_new (x_window_ids[i]);
+          window_list = g_list_append (window_list, window);
+        }
     }
 
-  XFree (windows);
+  XFree (x_window_ids);
 }
 
 static gboolean
@@ -85,12 +129,11 @@ on_expose_event (GtkWidget      *widget,
 }
 
 static gboolean
-do_update_state (PopOverlayWindow *window)
+do_update_state (PopOverlayWindow *overlay_window)
 {
-  free_window_list ();
-  create_window_list ();
+  static gboolean ran_before = FALSE;
 
-  gtk_widget_queue_draw (GTK_WIDGET (window));
+  refresh_window_list ();
 
   return TRUE;
 }
@@ -107,9 +150,68 @@ on_map (GtkWidget *widget)
   XCompositeRedirectSubwindows (GDK_DISPLAY (), 
                                 GDK_ROOT_WINDOW (), 
                                 CompositeRedirectManual);
+  do_update_state (POP_OVERLAY_WINDOW (widget));
+  pending_window_redraw_list = g_list_copy (window_list);
+  g_list_foreach (pending_window_redraw_list, (GFunc) g_object_ref, NULL);
   g_timeout_add (1000 / 60., (GSourceFunc) do_update_state, widget);
 }
 
+static gboolean
+x_event_is_damage_notify_event (XEvent *x_event)
+{
+  return x_event->type == damage_extension_event_base + XDamageNotify;
+}
+
+static void
+on_damage_notify_event (XDamageNotifyEvent *damage_notify_event,
+                        PopOverlayWindow   *overlay_window)
+{
+  GdkDisplay *display;
+  PopWindow *window;
+  Window x_window_id;
+
+  x_window_id = (Window) damage_notify_event->drawable;
+  window = find_window_from_x_window_id (x_window_id); 
+
+  gdk_error_trap_push ();
+
+  XDamageSubtract (GDK_DISPLAY (),
+                   damage_notify_event->damage,
+                   None, None);
+
+  gdk_flush ();
+  gdk_error_trap_pop ();
+
+
+  if (window == NULL)
+    return;
+
+ pending_window_redraw_list = g_list_append (pending_window_redraw_list, 
+                                             g_object_ref (window)); 
+}
+
+static gboolean
+redraw_pending_windows (PopOverlayWindow *overlay_window)
+{
+  if (pending_window_redraw_list != NULL)
+    gtk_widget_queue_draw (GTK_WIDGET (overlay_window));
+  return FALSE;
+}
+
+static GdkFilterReturn
+on_event (XEvent           *x_event,
+          GdkEvent         *event,
+          PopOverlayWindow *overlay_window)
+{
+   if (x_event_is_damage_notify_event (x_event))
+     on_damage_notify_event ((XDamageNotifyEvent *) x_event, overlay_window);
+
+  g_idle_add_full (GDK_PRIORITY_REDRAW, (GSourceFunc) redraw_pending_windows, 
+                   overlay_window, NULL);
+               
+  return GDK_FILTER_CONTINUE;
+}
+
 int
 main (int    argc,
       char **argv)
@@ -125,6 +227,12 @@ main (int    argc,
       return 1;
     }
 
+  if (!initialize_damage_extension ())
+    {
+      g_printerr ("damage extension not found\n"); 
+      return 2;
+    }
+
   overlay_window = pop_overlay_window_new ();
   gtk_container_set_border_width (GTK_CONTAINER (overlay_window), 200);
 
@@ -139,6 +247,8 @@ main (int    argc,
   gtk_container_add (GTK_CONTAINER (overlay_window), button);
   gtk_widget_show_all (overlay_window);
 
+  gdk_window_add_filter (NULL, (GdkFilterFunc) on_event, overlay_window);
+
   gtk_main();
 
   return 0;
diff --git a/pop-window.c b/pop-window.c
index 9186a8c..e2a6f72 100644
--- a/pop-window.c
+++ b/pop-window.c
@@ -26,17 +26,22 @@
 #include <glib-object.h>
 #include <glib/gi18n.h>
 
+#include <cairo.h>
+
+#include <X11/extensions/Xcomposite.h>
+#include <X11/extensions/Xdamage.h>
+
+#include <cairo-xlib.h>
 #include <gdk/gdkx.h>
+
 #include <gdk/gdk.h>
 
 #include <gtk/gtk.h>
 
-#include <cairo.h>
-#include <cairo-xlib.h>
-
 struct _PopWindowPrivate
 {
   Window x_window_id;
+  Damage x_damage_id;
   cairo_pattern_t *pattern;
 };
 
@@ -131,6 +136,24 @@ pop_window_class_install_properties (PopWindowClass *window_class)
 }
 
 static void
+pop_window_enable_damage_reporting (PopWindow *window)
+{
+  GtkWidget *widget;
+  GdkDisplay *display;
+
+  g_assert (POP_IS_WINDOW (window));
+
+  display = gdk_display_get_default ();
+
+  gdk_error_trap_push ();
+  window->priv->x_damage_id = XDamageCreate (GDK_DISPLAY_XDISPLAY (display),
+                                             window->priv->x_window_id,
+                                             XDamageReportNonEmpty);
+  gdk_flush ();
+  gdk_error_trap_pop ();
+}
+
+static void
 pop_window_init (PopWindow *window)
 {
   g_assert (POP_IS_WINDOW (window));
@@ -224,6 +247,7 @@ pop_window_set_x_window_id (PopWindow *window,
   if (window->priv->x_window_id != x_window_id)
     {
       window->priv->x_window_id = x_window_id;
+      pop_window_enable_damage_reporting (window);
       g_object_notify (G_OBJECT (window), "x-window-id");
     }
 }
@@ -310,33 +334,3 @@ pop_window_draw (PopWindow *window,
   cairo_set_source (cairo_context, window->priv->pattern);
   cairo_paint (cairo_context);
 }
-
-#ifdef POP_WINDOW_ENABLE_TEST
-
-#include <stdio.h>
-#include <glib.h>
-
-int
-main (int argc, char **argv)
-{
-  PopWindow *window;
-  int exit_code;
-
-  g_log_set_always_fatal (G_LOG_LEVEL_ERROR
-                          | G_LOG_LEVEL_CRITICAL | G_LOG_LEVEL_WARNING);
-
-  g_type_init ();
-
-  g_message ("creating instance of 'window' object...");
-  window = pop_window_new ();
-  g_message ("'window' object created successfully");
-
-  g_message ("destroying previously created 'window' object...");
-  g_object_unref (window);
-  g_message ("'window' object destroyed successfully");
-
-  exit_code = 0;
-
-  return exit_code;
-}
-#endif /* POP_WINDOW_ENABLE_TEST */