Check if the gamma value is not negative and

<255. based on a patch from  Patch from Gerard Klaver
<gerard@gkall.hobby.nl>, bug #300251.

Changelog

@@ -1,3 +1,9 @@
+2003-10-05  Henning Meier-Geinitz <henning@meier-geinitz.de>
+
+	* src/xscanimage.c: Check if the gamma value is not negative and
+	  <255. based on a patch from  Patch from Gerard Klaver
+	  <gerard@gkall.hobby.nl>, bug #300251.
+
 2003-09-30  Henning Meier-Geinitz <henning@meier-geinitz.de>
 
 	* src/xscanimage.c: Make sure that we save only to files with

src/xscanimage.c

@@ -1338,7 +1338,7 @@ update_double_callback (GtkWidget *widget, gpointer data)
     return;
 
   v = strtod (start, &end);
-  if (end > start && v > 0.0)
+  if (end > start)
     *valuep = v;
 }
 
@@ -1348,9 +1348,20 @@ preview_options_ok_callback (GtkWidget *widget, gpointer data)
   GtkWidget *dialog = data;
   char buf[1024];
 
+    				/* gamma min, max test*/
+  if (preferences.preview_gamma < 0.0 || preferences.preview_gamma > 255.0)
+    {  				
+      snprintf (buf, sizeof (buf), "Gamma value %g is < 0 or > 255, please change!",
+		preferences.preview_gamma);
+      gsg_warning (buf);
+      return;
+    }
+
+
   gtk_widget_destroy (dialog);
   pref_xscanimage_save ();
 
+
   snprintf (buf, sizeof (buf),
 	    "It is necessary to restart %s for the changes to take effect.",
 	    prog_name);