2 files changed, 24 insertions, 8 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 26ee254877a..86932ba4e9f 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,11 @@
 2001-05-30  Gerd Moellmann  <gerd@gnu.org>
 
+        * xfns.c (enum image_value_type): New enumerator
+        IMAGE_STRING_OR_NIL_VALUE.
+        (parse_image_spec): Handle it.
+        (xbm_format, pbm_format): Use it for :foreground and :background.
+        (xbm_load, pbm_load): Check for nil color names.
+
         * xterm.c (note_mouse_highlight): If an overlapping overlay
         exists, but we find that we highlight the same overlay as before,
         don't do the highlighting again.
diff --git a/src/xfns.c b/src/xfns.c
index 485a2f9b4c7..53e7f090ef6 100644
--- a/src/xfns.c
+++ b/src/xfns.c
@@ -5324,6 +5324,7 @@ enum image_value_type
 {
   IMAGE_DONT_CHECK_VALUE_TYPE,
   IMAGE_STRING_VALUE,
+  IMAGE_STRING_OR_NIL_VALUE,
   IMAGE_SYMBOL_VALUE,
   IMAGE_POSITIVE_INTEGER_VALUE,
   IMAGE_POSITIVE_INTEGER_VALUE_OR_PAIR,
@@ -5421,6 +5422,11 @@ parse_image_spec (spec, keywords, nkeywords, type)
             return 0;
           break;
 
+        case IMAGE_STRING_OR_NIL_VALUE:
+          if (!STRINGP (value) && !NILP (value))
+            return 0;
+          break;
+
         case IMAGE_SYMBOL_VALUE:
           if (!SYMBOLP (value))
             return 0;
@@ -6384,8 +6390,8 @@ static struct image_keyword xbm_format[XBM_LAST] =
   {":width",            IMAGE_POSITIVE_INTEGER_VALUE,           0},
   {":height",           IMAGE_POSITIVE_INTEGER_VALUE,           0},
   {":data",             IMAGE_DONT_CHECK_VALUE_TYPE,            0},
-  {":foreground",       IMAGE_STRING_VALUE,                     0},
-  {":background",       IMAGE_STRING_VALUE,                     0},
+  {":foreground",       IMAGE_STRING_OR_NIL_VALUE,              0},
+  {":background",       IMAGE_STRING_OR_NIL_VALUE,              0},
   {":ascent",           IMAGE_ASCENT_VALUE,                     0},
   {":margin",           IMAGE_POSITIVE_INTEGER_VALUE_OR_PAIR,   0},
   {":relief",           IMAGE_INTEGER_VALUE,                    0},
@@ -6919,10 +6925,12 @@ xbm_load (f, img)
         }
 
       /* Get foreground and background colors, maybe allocate colors.  */
-      if (fmt[XBM_FOREGROUND].count)
+      if (fmt[XBM_FOREGROUND].count
+          && STRINGP (fmt[XBM_FOREGROUND].value))
         foreground = x_alloc_image_color (f, img, fmt[XBM_FOREGROUND].value,
                                           foreground);
-      if (fmt[XBM_BACKGROUND].count)
+      if (fmt[XBM_BACKGROUND].count
+          && STRINGP (fmt[XBM_BACKGROUND].value))
         background = x_alloc_image_color (f, img, fmt[XBM_BACKGROUND].value,
                                           background);
 
@@ -8110,8 +8118,8 @@ static struct image_keyword pbm_format[PBM_LAST] =
   {":conversion",       IMAGE_DONT_CHECK_VALUE_TYPE,            0},
   {":heuristic-mask",   IMAGE_DONT_CHECK_VALUE_TYPE,            0},
   {":mask",             IMAGE_DONT_CHECK_VALUE_TYPE,            0},
-  {":foreground",       IMAGE_STRING_VALUE,                     0},
-  {":background",       IMAGE_STRING_VALUE,                     0}
+  {":foreground",       IMAGE_STRING_OR_NIL_VALUE,              0},
+  {":background",       IMAGE_STRING_OR_NIL_VALUE,              0}
 };
 
 /* Structure describing the image type `pbm'.  */
@@ -8309,9 +8317,11 @@ pbm_load (f, img)
       parse_image_spec (img->spec, fmt, PBM_LAST, Qpbm);
       
       /* Get foreground and background colors, maybe allocate colors.  */
-      if (fmt[PBM_FOREGROUND].count)
+      if (fmt[PBM_FOREGROUND].count
+          && STRINGP (fmt[PBM_FOREGROUND].value))
         fg = x_alloc_image_color (f, img, fmt[PBM_FOREGROUND].value, fg);
-      if (fmt[PBM_BACKGROUND].count)
+      if (fmt[PBM_BACKGROUND].count
+          && STRINGP (fmt[PBM_BACKGROUND].value))
         bg = x_alloc_image_color (f, img, fmt[PBM_BACKGROUND].value, bg);
       
       for (y = 0; y < height; ++y)