Index: trunk/Ohana/src/opihi/cmd.astro/Makefile
===================================================================
--- trunk/Ohana/src/opihi/cmd.astro/Makefile	(revision 31667)
+++ trunk/Ohana/src/opihi/cmd.astro/Makefile	(revision 32632)
@@ -43,4 +43,5 @@
 $(SRC)/galprofiles.$(ARCH).o	   \
 $(SRC)/elliprofile.$(ARCH).o	   \
+$(SRC)/ringflux.$(ARCH).o	   \
 $(SRC)/petrosian.$(ARCH).o	   \
 $(SRC)/multifit.$(ARCH).o	   \
Index: trunk/Ohana/src/opihi/cmd.astro/init.c
===================================================================
--- trunk/Ohana/src/opihi/cmd.astro/init.c	(revision 31667)
+++ trunk/Ohana/src/opihi/cmd.astro/init.c	(revision 32632)
@@ -29,4 +29,5 @@
 int galradbins              PROTO((int, char **));
 int elliprofile             PROTO((int, char **));
+int ringflux                PROTO((int, char **));
 int petrosian               PROTO((int, char **));
 int mkgauss                 PROTO((int, char **));
@@ -78,4 +79,5 @@
   {1, "galradbins",  galradbins,   "generate radial vectors with interpolation along paths"},
   {1, "elliprofile", elliprofile,  "generate radial vectors with interpolation along paths"},
+  {1, "ringflux",    ringflux,     "mean flux in a ring"},
   {1, "petrosian",   petrosian,    "petrosian parameters given radial bins"},
   {1, "multifit",    multifit,     "fit multi-order spectrum"},
Index: trunk/Ohana/src/opihi/cmd.astro/ringflux.c
===================================================================
--- trunk/Ohana/src/opihi/cmd.astro/ringflux.c	(revision 32632)
+++ trunk/Ohana/src/opihi/cmd.astro/ringflux.c	(revision 32632)
@@ -0,0 +1,100 @@
+# include "astro.h"
+
+# define FLUX(BUF,X,Y) {						\
+	char valid = TRUE;						\
+	valid &= (X >= 0);						\
+	valid &= (Y >= 0);						\
+	valid &= (X < Nx);						\
+	valid &= (Y < Ny);						\
+	if (valid) {							\
+	    out[Nvec] = BUF[(int)(X) + ((int)(Y))*Nx];			\
+	    Nvec++;							\
+	    if (Nvec >= vec[0].Nelements) abort();			\
+	}								\
+    }
+
+# define C1 0
+
+int ringflux (int argc, char **argv) {
+  
+  int Nx, Ny, x, y, d, radius, Radius, dRadius, Nvec;
+  double *out;
+  float *in;
+  float Xo, Yo;
+  Buffer *buf;
+  Vector *vec;
+
+  if (argc != 7) {
+    gprint (GP_ERR, "USAGE: ringflux (buffer) (vector) (Xo) (Yo) (Radius) (dRadius)\n");
+    return (FALSE);
+  }
+
+  /* select input / output buffers */
+  if ((buf = SelectBuffer (argv[1], OLDBUFFER, TRUE)) == NULL) return (FALSE);
+  if ((vec = SelectVector (argv[2], ANYVECTOR, TRUE)) == NULL) return (FALSE);
+
+  Nx = buf[0].header.Naxis[0];
+  Ny = buf[0].header.Naxis[1];
+
+  Xo = atof(argv[3]);
+  Yo = atof(argv[4]);
+
+  Radius = atoi (argv[5]);
+  dRadius = atoi (argv[6]);
+
+  // just a rough guess at the number needed
+  ResetVector (vec, OPIHI_FLT, MAX (6*Radius*dRadius, 8));
+
+  Nvec = 0;
+  for (radius = Radius; radius < Radius + dRadius; radius ++) {
+
+    x = 0;
+    y = radius;
+
+# if (C1)
+    d = 3 - 2*radius;
+# else
+    d = 5 - 4*radius;
+# endif
+
+    in = (float *) buf[0].matrix.buffer;
+    out = vec[0].elements.Flt;
+
+    while (x <= y) {
+      FLUX(in, (Xo + x), (Yo + y));
+      FLUX(in, (Xo + x), (Yo - y));
+      FLUX(in, (Xo + y), (Yo + x));
+      FLUX(in, (Xo - y), (Yo + x));
+
+      if (x > 0) {
+	FLUX(in, (Xo - x), (Yo + y));
+	FLUX(in, (Xo - x), (Yo - y));
+	FLUX(in, (Xo - y), (Yo - x));
+	FLUX(in, (Xo + y), (Yo - x));
+      }
+      if (Nvec >= vec[0].Nelements - 8) {
+	  // counting error here
+	ResetVector (vec, OPIHI_FLT, vec[0].Nelements + 64);
+	out = vec[0].elements.Flt;
+      }
+
+      if (d < 0) {
+# if (C1)      
+	d = d + 4*x + 6;
+# else
+	d = d + 8*x + 4;
+# endif
+      } else {
+# if (C1)      
+	d = d + 4*(x-y) + 10;
+# else
+	d = d + 8*(x-y) + 8;
+# endif
+	y--;
+      }
+      x++;
+    }
+  }
+  vec[0].Nelements = Nvec;
+  return (TRUE);
+}