Index: trunk/pswarp/src/pswarpPixelsLit.c
===================================================================
--- trunk/pswarp/src/pswarpPixelsLit.c	(revision 23688)
+++ trunk/pswarp/src/pswarpPixelsLit.c	(revision 35563)
@@ -64,26 +64,18 @@
     for (int y = 0; y < numRows; y++) {
         for (int x = 0; x < numCols; x++) {
-            if (!(mask->data.PS_TYPE_IMAGE_MASK_DATA[y][x] & maskValue)) {
-                if (y > yMax) {
-                    yMax = y;
-                }
-                if (y < yMin) {
-                    yMin = y;
-                }
-                if (x > xMax) {
-                    xMax = x;
-                }
-                if (x < xMin) {
-                    xMin = x;
-                }
-            }
+	    if (mask->data.PS_TYPE_IMAGE_MASK_DATA[y][x] & maskValue) { continue; }
+	    xMin = PS_MIN (xMin, x);
+	    xMax = PS_MAX (xMax, x);
+	    yMin = PS_MIN (yMin, y);
+	    yMax = PS_MAX (yMax, y);
         }
     }
 
     if (stats) {
-        psMetadataAddS32(stats, PS_LIST_TAIL, "RANGE.XMIN", 0, "Minimum valid x value", xMin);
-        psMetadataAddS32(stats, PS_LIST_TAIL, "RANGE.XMAX", 0, "Maximum valid x value", xMax);
-        psMetadataAddS32(stats, PS_LIST_TAIL, "RANGE.YMIN", 0, "Minimum valid y value", yMin);
-        psMetadataAddS32(stats, PS_LIST_TAIL, "RANGE.YMAX", 0, "Maximum valid y value", yMax);
+	// XXX with multiple inputs (eg, output stacks -> exposure), these only represent the last input
+        psMetadataAddS32(stats, PS_LIST_TAIL, "RANGE.XMIN", PS_META_REPLACE, "Minimum valid x value", xMin);
+        psMetadataAddS32(stats, PS_LIST_TAIL, "RANGE.XMAX", PS_META_REPLACE, "Maximum valid x value", xMax);
+        psMetadataAddS32(stats, PS_LIST_TAIL, "RANGE.YMIN", PS_META_REPLACE, "Minimum valid y value", yMin);
+        psMetadataAddS32(stats, PS_LIST_TAIL, "RANGE.YMAX", PS_META_REPLACE, "Maximum valid y value", yMax);
     }