Index: trunk/psphot/src/psUtils.c
===================================================================
--- trunk/psphot/src/psUtils.c	(revision 4188)
+++ trunk/psphot/src/psUtils.c	(revision 4251)
@@ -1,21 +1,3 @@
 # include "psphot.h"
-
-// set actual region based on image parameters
-// XXX EAM : this needs to be changes to use psRegion rather than psRegion*
-psRegion *psRegionForImage (psRegion *out, psImage *image, psRegion *in) {
-    
-    if (out == NULL) {
-	out = psRegionAlloc(in->x0, in->x1, in->y0, in->y1);
-    } else {
-	*out = *in;
-    }
-    if (out->x1 <= 0) {
-	out->x1 = image->numCols + out->x1;
-    }
-    if (out->y1 <= 0) {
-	out->y1 = image->numRows + out->y1;
-    }
-    return (out);
-}
 
 static psHash *timers = NULL;
@@ -336,2 +318,132 @@
   return (false);
 }	    
+
+// define a square region centered on the given coordinate
+psRegion *psRegionSquare (psF32 x, psF32 y, psF32 radius) {
+    psRegion *region;
+    region = psRegionAlloc (x - radius, x + radius + 1,    
+			    y - radius, y + radius + 1);
+    return (region);
+}
+
+// set actual region based on image parameters:
+// compensate for negative upper limits
+// XXX this is inconsistent: the coordindates should always be in the parent
+//     frame, which means the negative values should subtract from Nx,Ny of
+//     the parent, not the child.  but, we don't carry the dimensions of the 
+//     parent in the psImage container.  for now, us the child Nx,Ny
+// force range to be on this subimage 
+// XXX EAM : this needs to be changes to use psRegion rather than psRegion*
+psRegion *psRegionForImage (psRegion *out, psImage *image, psRegion *in) {
+    
+    // x0,y0, x1,y1 are in *parent* units
+
+    if (out == NULL) {
+	out = psRegionAlloc(in->x0, in->x1, in->y0, in->y1);
+    } else {
+	*out = *in;
+    }
+    // XXX these are probably wrong (see above)
+    if (out->x1 <= 0) {
+	out->x1 = image->col0 + image->numCols + out->x1;
+    }
+    if (out->y1 <= 0) {
+	out->y1 = image->row0 + image->numRows + out->y1;
+    }
+
+    // force the lower-limits to be on the child
+    out->x0 = PS_MAX(image->col0, out->x0);
+    out->y0 = PS_MAX(image->row0, out->y0);
+
+    // force the upper-limits to be on the child
+    out->x1 = PS_MIN(image->col0 + image->numCols, out->x1);
+    out->y1 = PS_MIN(image->row0 + image->numRows, out->y1);
+    return (out);
+}
+
+// mask the area contained by the region
+// the region is defined wrt the parent image
+void psImageMaskRegion (psImage *image, psRegion *region, bool logical_and, int maskValue) {
+
+    for (int iy = 0; iy < image->numRows; iy++) {
+	for (int ix = 0; ix < image->numCols; ix++) {
+	    if (ix + image->col0 <  region->x0) continue;
+	    if (ix + image->col0 >= region->x1) continue;
+	    if (iy + image->row0 <  region->y0) continue;
+	    if (iy + image->row0 >= region->y1) continue;
+	    if (logical_and) {
+		image->data.U8[iy][ix] &= maskValue;
+	    } else {
+		image->data.U8[iy][ix] |= maskValue;
+	    }
+	}
+    }
+}
+
+// mask the area not contained by the region
+// the region is defined wrt the parent image
+void psImageKeepRegion (psImage *image, psRegion *region, bool logical_and, int maskValue) {
+
+    for (int iy = 0; iy < image->numRows; iy++) {
+	for (int ix = 0; ix < image->numCols; ix++) {
+	    if (ix + image->col0 <  region->x0) goto maskit;
+	    if (ix + image->col0 >= region->x1) goto maskit;
+	    if (iy + image->row0 <  region->y0) goto maskit;
+	    if (iy + image->row0 >= region->y1) goto maskit;
+	    continue;
+	maskit:
+	    if (logical_and) {
+		image->data.U8[iy][ix] &= maskValue;
+	    } else {
+		image->data.U8[iy][ix] |= maskValue;
+	    }
+	}
+    }
+}
+
+// mask the area contained by the region
+// the region is defined wrt the parent image
+void psImageMaskCircle (psImage *image, double x, double y, double radius, bool logical_and, int maskValue) {
+
+    double dx, dy, r2, R2;
+
+    R2 = PS_SQR(radius);
+
+    for (int iy = 0; iy < image->numRows; iy++) {
+	for (int ix = 0; ix < image->numCols; ix++) {
+	    dx = ix + image->col0 - x;
+	    dy = iy + image->row0 - y;
+	    r2 = PS_SQR(dx) + PS_SQR(dy);
+	    if (r2 > R2) continue;
+	    if (logical_and) {
+		image->data.U8[iy][ix] &= maskValue;
+	    } else {
+		image->data.U8[iy][ix] |= maskValue;
+	    }
+	}
+    }
+}
+
+// mask the area contained by the region
+// the region is defined wrt the parent image
+void psImageKeepCircle (psImage *image, double x, double y, double radius, bool logical_and, int maskValue) {
+
+    double dx, dy, r2, R2;
+
+    R2 = PS_SQR(radius);
+
+    for (int iy = 0; iy < image->numRows; iy++) {
+	for (int ix = 0; ix < image->numCols; ix++) {
+	    dx = ix + image->col0 - x;
+	    dy = iy + image->row0 - y;
+	    r2 = PS_SQR(dx) + PS_SQR(dy);
+	    if (r2 < R2) continue;
+	    if (logical_and) {
+		image->data.U8[iy][ix] &= maskValue;
+	    } else {
+		image->data.U8[iy][ix] |= maskValue;
+	    }
+	}
+    }
+}
+