From http://www.jwz.org/xscreensaver/xscreensaver-5.35.tar.gz

[xscreensaver] / utils / visual.c

diff --git a/utils/visual.c b/utils/visual.c
index 7c89f5a0c7a55bcdcbc3b70aed3d56c9afab2aab..89b4f33e69f3d7af84fc2a5931ae594c1916a47e 100644 (file)
--- a/utils/visual.c
+++ b/utils/visual.c
@@ -1,7 +1,4 @@
-/* xscreensaver, Copyright (c) 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2003, 2006
- * 
- * 
- *  by Jamie Zawinski <jwz@jwz.org>
+/* xscreensaver, Copyright (c) 1993-2014 by Jamie Zawinski <jwz@jwz.org>
  *
  * Permission to use, copy, modify, distribute, and sell this software and its
  * documentation for any purpose is hereby granted without fee, provided that
@@ -22,11 +19,14 @@
 #include "visual.h"
 
 #include <string.h>
+#ifndef HAVE_ANDROID
 #include <X11/Xutil.h>
+#else
+#include "../android/android-visual.h"
+#endif
 
 extern char *progname;
 
-
 #ifndef isupper
 # define isupper(c)  ((c) >= 'A' && (c) <= 'Z')
 #endif
@@ -298,7 +298,7 @@ pick_best_gl_visual (Screen *screen)
 
   int ndepths = 0;
   int *depths = XListDepths (dpy, screen_number (screen), &ndepths);
-  int screen_depth = depths[ndepths];
+  int screen_depth = (depths && ndepths) ? depths[ndepths - 1] : 0;
   XFree (depths);
 
   vi_in.class = TrueColor;
@@ -542,3 +542,48 @@ find_similar_visual(Screen *screen, Visual *old_visual)
 
   return result;
 }
+
+
+int
+get_bits_per_pixel(Display *dpy, int depth)
+{
+  unsigned i = 0;
+  int count, result;
+  XPixmapFormatValues *formats = XListPixmapFormats(dpy, &count);
+
+  /* XCreateImage calls _XGetBitsPerPixel to figure this out, but that function
+     is private to Xlib.
+
+     For some reason, _XGetBitsPerPixel tries a hard-coded list of depths if
+     it doesn't find a matching pixmap format, but I (Dave Odell) couldn't
+     find any justification for this in the X11 spec. And the XFree86 CVS
+     repository doesn't quite go back far enough to shed any light on what
+     the deal is with that.
+     http://cvsweb.xfree86.org/cvsweb/xc/lib/X11/ImUtil.c
+
+     The hard-coded list apparently was added between X11R5 and X11R6.
+     See <ftp://ftp.x.org/pub/>.
+   */
+
+  if (!formats) return 0;
+
+  for (;;)
+    {
+      if (i == (unsigned)count)
+        {
+          result = 0;
+          break;
+        }
+
+      if (formats[i].depth == depth)
+        {
+          result = formats[i].bits_per_pixel;
+          break;
+        }
+
+      ++i;
+    }
+
+  XFree (formats);
+  return result;
+}