Index: trunk/pswarp/src/pswarpMaskStats.c
===================================================================
--- trunk/pswarp/src/pswarpMaskStats.c	(revision 28130)
+++ trunk/pswarp/src/pswarpMaskStats.c	(revision 35563)
@@ -1,4 +1,3 @@
 #include "pswarp.h"
-#include <ppStats.h>
 
 bool pswarpMaskStats(const pmReadout *readout, psMetadata *stats, const pmConfig *config)
@@ -31,16 +30,13 @@
                               dynamicMaskVal,advisoryMaskVal)) {
     psError(PS_ERR_UNKNOWN, false, "Unable to calculate masks for readout.");
-    return(false);
+    return false;
   }
-  psMetadataAddS32(stats, PS_LIST_TAIL,"MASKFRAC_NPIX", 0,
-                   "Number of valid pixels", Npix_valid);
-  psMetadataAddF32(stats,PS_LIST_TAIL, "MASKFRAC_STATIC", 0,
-                   "Fraction of pixels statically masked", (float) Npix_static / Npix_valid);
-  psMetadataAddF32(stats,PS_LIST_TAIL, "MASKFRAC_DYNAMIC", 0,
-                   "Fraction of pixels dynamically masked", (float) Npix_dynamic / Npix_valid);
-  psMetadataAddF32(stats,PS_LIST_TAIL, "MASKFRAC_MAGIC", 0,
-                   "Fraction of pixels magically masked", (float) Npix_magic / Npix_valid);
-  psMetadataAddF32(stats,PS_LIST_TAIL, "MASKFRAC_ADVISORY", 0,
-                   "Fraction of pixels masked as an advisory", (float) Npix_advisory / Npix_valid);
-  return(true);
+
+  // XXX with multiple inputs (eg, output stacks -> exposure), these only represent the last input
+  psMetadataAddS32(stats, PS_LIST_TAIL,"MASKFRAC_NPIX",     PS_META_REPLACE, "Number of valid pixels", Npix_valid);
+  psMetadataAddF32(stats,PS_LIST_TAIL, "MASKFRAC_STATIC",   PS_META_REPLACE, "Fraction of pixels statically masked", (float) Npix_static / Npix_valid);
+  psMetadataAddF32(stats,PS_LIST_TAIL, "MASKFRAC_DYNAMIC",  PS_META_REPLACE, "Fraction of pixels dynamically masked", (float) Npix_dynamic / Npix_valid);
+  psMetadataAddF32(stats,PS_LIST_TAIL, "MASKFRAC_MAGIC",    PS_META_REPLACE, "Fraction of pixels magically masked", (float) Npix_magic / Npix_valid);
+  psMetadataAddF32(stats,PS_LIST_TAIL, "MASKFRAC_ADVISORY", PS_META_REPLACE, "Fraction of pixels masked as an advisory", (float) Npix_advisory / Npix_valid);
+  return true;
 }