From 41293ef7559c2b6ed8f97ee3634f6399ccd241e7 Mon Sep 17 00:00:00 2001
From: Keith Packard <keithp@keithp.com>
Date: Mon, 10 Nov 2003 18:34:35 +0000
Subject: [PATCH] Track changes to _XROOTPMAP_ID property

---
 ChangeLog  |  6 ++++++
 Makefile   |  2 ++
 xcompmgr.c | 20 ++++++++++++++++++--
 3 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 3eea662..bbc41dc 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2003-11-10  Keith Packard  <keithp@keithp.com>
+
+	* Makefile:
+	* xcompmgr.c: (root_tile), (main):
+	Track changes to _XROOTPMAP_ID property
+
 2003-11-09  Keith Packard  <keithp@keithp.com>
 
 	* xcompmgr.c: (time_in_millis), (main):
diff --git a/Makefile b/Makefile
index f3c7dea..139ed49 100644
--- a/Makefile
+++ b/Makefile
@@ -1,5 +1,7 @@
 LIBS=`pkg-config --cflags --libs xcomposite xfixes xdamage xrender` -lm
 
+CFLAGS=-O -g
+
 xcompmgr: xcompmgr.c
 	$(CC) -o $@ $(CFLAGS) xcompmgr.c $(LIBS)
 
diff --git a/xcompmgr.c b/xcompmgr.c
index 0662b82..299a511 100644
--- a/xcompmgr.c
+++ b/xcompmgr.c
@@ -65,6 +65,7 @@ Picture		rootTile;
 XserverRegion	allDamage;
 int		root_height, root_width;
 
+#define BACKGROUND_PROP	"_XROOTPMAP_ID"
 #define WINDOW_PLAIN	0
 #define WINDOW_DROP	1
 #define WINDOW_TRANS	2
@@ -326,7 +327,7 @@ root_tile (Display *dpy)
     Bool	    fill;
     XRenderPictureAttributes	pa;
 
-    if (XGetWindowProperty (dpy, root, XInternAtom (dpy, "_XROOTPMAP_ID", False),
+    if (XGetWindowProperty (dpy, root, XInternAtom (dpy, BACKGROUND_PROP, False),
 			    0, 4, False, AnyPropertyType,
 			    &actual_type, &actual_format, &nitems, &bytes_after, &prop) == Success &&
 	actual_type == XInternAtom (dpy, "PIXMAP", False) && actual_format == 32 && nitems == 1)
@@ -816,7 +817,11 @@ main ()
     XGrabServer (dpy);
     XCompositeRedirectSubwindows (dpy, root, CompositeRedirectManual);
     paint_all (dpy, None);
-    XSelectInput (dpy, root, SubstructureNotifyMask|ExposureMask|StructureNotifyMask);
+    XSelectInput (dpy, root, 
+		  SubstructureNotifyMask|
+		  ExposureMask|
+		  StructureNotifyMask|
+		  PropertyChangeMask);
     XQueryTree (dpy, root, &root_return, &parent_return, &children, &nchildren);
     for (i = 0; i < nchildren; i++)
 	add_win (dpy, children[i], i ? children[i-1] : None);
@@ -882,6 +887,17 @@ main ()
 		    }
 		}
 		break;
+	    case PropertyNotify:
+		if (ev.xproperty.atom == XInternAtom (dpy, BACKGROUND_PROP, False))
+		{
+		    if (rootTile)
+		    {
+			XClearArea (dpy, root, 0, 0, 0, 0, True);
+			XRenderFreePicture (dpy, rootTile);
+			rootTile = None;
+		    }
+		}
+		break;
 	    default:
 		if (ev.type == damage_event + XDamageNotify)
 		    damage_win (dpy, (XDamageNotifyEvent *) &ev);
-- 
1.9.1