Bug#448360: Doesn't deal correctly with MIT-SHM extension not supporting shared pixmaps

[Michel Dänzer <daenzer@debian.org>]

Package: imlib
Version: 1.9.15-3
Severity: important
Tags: patch

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* The boolean value returned via the last parameter to XShmQueryVersion()
  isn't honoured everywhere.
* The init functions that take parameters allow the caller to enable shared
  pixmaps when they aren't supported (or disabled by configuration files).


These result in incorrect rendering when the MIT-SHM extension doesn't support
shared pixmaps, e.g. using EXA with current versions of Xorg. I wonder if bug
#414886 could be related to this as well.


The attached patch fixes these problems.


- -- System Information:
Debian Release: lenny/sid
  APT prefers unstable
  APT policy: (500, 'unstable'), (500, 'stable'), (102, 'experimental'), (101, 'gutsy-security'), (101, 'gutsy')
Architecture: powerpc (ppc)

Kernel: Linux 2.6.22-2-powerpc
Locale: LANG=de_CH.UTF-8, LC_CTYPE=de_CH.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash

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diff -up -ru imlib-1.9.15.orig/gdk_imlib/misc.c imlib-1.9.15/gdk_imlib/misc.c
--- imlib-1.9.15.orig/gdk_imlib/misc.c	2002-03-04 18:06:32.000000000 +0100
+++ imlib-1.9.15/gdk_imlib/misc.c	2007-10-28 14:00:04.000000000 +0100
@@ -674,6 +674,10 @@ gdk_imlib_init_params(GdkImlibInitParams
   visual = gdk_rgb_get_visual();
   id->x.visual = GDK_VISUAL_XVISUAL(visual);	/* the visual type */
   id->x.depth = visual->depth;	/* the depth of the screen in bpp */
+
+  id->x.shm = 0;
+  id->x.shmp = 0;
+  id->max_shm = 0;
 #ifdef HAVE_SHM
   if (XShmQueryExtension(id->x.disp))
     {
@@ -689,17 +693,14 @@ gdk_imlib_init_params(GdkImlibInitParams
 	      id->x.last_xim = NULL;
 	      id->x.last_sxim = NULL;
 	      id->max_shm = 0x7fffffff;
-	      if (XShmPixmapFormat(id->x.disp) == ZPixmap)
+	      if ((XShmPixmapFormat(id->x.disp) == ZPixmap) &&
+		  (pm == True))
 		id->x.shmp = 1;
 	    }
 	}
     }
-  else
 #endif
-    {
-      id->x.shm = 0;
-      id->x.shmp = 0;
-    }
+
   id->cache.on_image = 0;
   id->cache.size_image = 0;
   id->cache.num_image = 0;
@@ -935,8 +936,8 @@ gdk_imlib_init_params(GdkImlibInitParams
 	}
       if (p->flags & PARAMS_SHAREDPIXMAPS)
 	{
-	  if (id->x.shm)
-	    id->x.shmp = p->sharedpixmaps;
+	  if (!p->sharedpixmaps)
+	    id->x.shmp = 0;
 	}
       if (p->flags & PARAMS_PALETTEOVERRIDE)
 	override = p->paletteoverride;
diff -up -ru imlib-1.9.15.orig/Imlib/misc.c imlib-1.9.15/Imlib/misc.c
--- imlib-1.9.15.orig/Imlib/misc.c	2004-09-21 02:22:59.000000000 +0200
+++ imlib-1.9.15/Imlib/misc.c	2007-10-28 14:00:23.000000000 +0100
@@ -675,6 +675,10 @@ Imlib_init_with_params(Display * disp, I
   id->x.root = DefaultRootWindow(disp);		/* the root window id */
   id->x.visual = DefaultVisual(disp, id->x.screen);	/* the visual type */
   id->x.depth = DefaultDepth(disp, id->x.screen);	/* the depth of the screen in bpp */
+
+  id->x.shm = 0;
+  id->x.shmp = 0;
+  id->max_shm = 0;
 #ifdef HAVE_SHM
   if (XShmQueryExtension(id->x.disp))
     {
@@ -690,17 +694,14 @@ Imlib_init_with_params(Display * disp, I
 	      id->x.last_xim = NULL;
 	      id->x.last_sxim = NULL;
 	      id->max_shm = 0x7fffffff;
-	      if (XShmPixmapFormat(id->x.disp) == ZPixmap)
+	      if ((XShmPixmapFormat(id->x.disp) == ZPixmap &&
+		   (pm == True)))
 		id->x.shmp = 1;
 	    }
 	}
     }
-  else
 #endif
-    {
-      id->x.shm = 0;
-      id->x.shmp = 0;
-    }
+
   id->cache.on_image = 0;
   id->cache.size_image = 0;
   id->cache.num_image = 0;
@@ -952,8 +953,8 @@ Imlib_init_with_params(Display * disp, I
 	}
       if (p->flags & PARAMS_SHAREDPIXMAPS)
 	{
-	  if (id->x.shm)
-	    id->x.shmp = p->sharedpixmaps;
+	  if (!p->sharedpixmaps)
+	    id->x.shmp = 0;
 	}
       if (p->flags & PARAMS_PALETTEOVERRIDE)
 	override = p->paletteoverride;