http://www.ibiblio.org/pub/historic-linux/ftp-archives/sunsite.unc.edu/Sep-29-1996...

[xscreensaver] / utils / fade.c

diff --git a/utils/fade.c b/utils/fade.c
index 2fbb2e97fa4f872609c6413ff5ca243977c57982..40fe9dddc486cff338fca43fd09fcca790b607d9 100644 (file)
--- a/utils/fade.c
+++ b/utils/fade.c
@@ -1,4 +1,4 @@
-/* xscreensaver, Copyright (c) 1992 Jamie Zawinski <jwz@lucid.com>
+/* xscreensaver, Copyright (c) 1992 Jamie Zawinski <jwz@netscape.com>
  *
  * Permission to use, copy, modify, distribute, and sell this software and its
  * documentation for any purpose is hereby granted without fee, provided that
@@ -18,13 +18,13 @@
 #include <X11/Xos.h>
 
 #if __STDC__
-# define bcopy(from,to,size) memcpy((to),(from),(size))
-# define bzero(addr,size) memset((addr),0,(size))
-extern void screenhack_usleep (unsigned long);
+# define P(x)x
 #else
-extern void screenhack_usleep ();
+# define P(x)()
 #endif
 
+extern int get_visual_class P((Display *, Visual *));
+extern void screenhack_usleep P((int));
 #define usleep screenhack_usleep
 
 #define MAX_COLORS 4096
@@ -38,13 +38,23 @@ copy_colormap (dpy, cmap, into_cmap)
      Colormap cmap, into_cmap;
 {
   int i;
-  ncolors = CellsOfScreen (DefaultScreenOfDisplay (dpy));
+  Screen *screen = DefaultScreenOfDisplay (dpy);
+  Visual *visual = DefaultVisualOfScreen (screen);
+  Window window = RootWindowOfScreen (screen);
+  int vclass = get_visual_class (dpy, visual);
+
+  ncolors = CellsOfScreen (screen);
+
+  /* If this is a colormap on a mono visual, or one with insanely many
+     color cells, bug out. */
   if (ncolors <= 2 || ncolors > MAX_COLORS)
     return 0;
+  /* If this is a non-writable visual, bug out. */
+  if (vclass == StaticGray || vclass == StaticColor || vclass == TrueColor)
+    return 0;
+
   if (! into_cmap)
-    into_cmap = XCreateColormap (dpy, RootWindow (dpy, DefaultScreen (dpy)),
-                                DefaultVisual (dpy, DefaultScreen (dpy)),
-                                AllocAll);
+    into_cmap = XCreateColormap (dpy, window, visual, AllocAll);
   if (! cmap)
     cmap = DefaultColormap (dpy, DefaultScreen (dpy));
   for (i = 0; i < ncolors; i++)
@@ -87,7 +97,7 @@ fade_colormap (dpy, cmap, cmap2, seconds, ticks, out_p)
   for (i = 0; i < ncolors; i++)
     orig_colors [i].pixel = i;
   XQueryColors (dpy, cmap, orig_colors, ncolors);
-  bcopy (orig_colors, current_colors, ncolors * sizeof (XColor));
+  memcpy (current_colors, orig_colors, ncolors * sizeof (XColor));
 
   for (i = (out_p ? steps : 0);
        (out_p ? i > 0 : i < steps);