Index: trunk/psModules/src/objects/pmSourceVisual.c
===================================================================
--- trunk/psModules/src/objects/pmSourceVisual.c	(revision 25979)
+++ trunk/psModules/src/objects/pmSourceVisual.c	(revision 26260)
@@ -73,4 +73,167 @@
 
     float range;
+    range = graphdata.xmax - graphdata.xmin;
+    graphdata.xmax += 0.05*range;
+    graphdata.xmin -= 0.05*range;
+    range = graphdata.ymax - graphdata.ymin;
+    graphdata.ymax += 0.05*range;
+    graphdata.ymin -= 0.05*range;
+
+    // better choice for range?
+    // graphdata.xmin = -17.0;
+    // graphdata.xmax =  -9.0;
+    graphdata.ymin = -0.51;
+    graphdata.ymax = +0.51;
+
+    KapaSetLimits (kapa1, &graphdata);
+
+    KapaSetFont (kapa1, "helvetica", 14);
+    KapaBox (kapa1, &graphdata);
+    KapaSendLabel (kapa1, "PSF Mag", KAPA_LABEL_XM);
+    KapaSendLabel (kapa1, "Ap Mag - PSF Mag", KAPA_LABEL_YM);
+
+    graphdata.color = KapaColorByName ("black");
+    graphdata.ptype = 2;
+    graphdata.size = 0.5;
+    graphdata.style = 2;
+    graphdata.etype |= 0x01;
+
+    KapaPrepPlot (kapa1, n, &graphdata);
+    KapaPlotVector (kapa1, n, x->data.F32, "x");
+    KapaPlotVector (kapa1, n, y->data.F32, "y");
+    KapaPlotVector (kapa1, n, dy->data.F32, "dym");
+    KapaPlotVector (kapa1, n, dy->data.F32, "dyp");
+
+    psFree (x);
+    psFree (y);
+    psFree (dy);
+
+    pmVisualAskUser(NULL);
+    return true;
+}
+
+bool pmSourceVisualPlotPSFMetricSubpix (pmPSFtry *psfTry) {
+
+    KapaSection section;  // put the positive profile in one and the residuals in another?
+    Graphdata graphdata;
+
+    if (!pmVisualIsVisual()) return true;
+
+    if (kapa1 == -1) {
+        kapa1 = KapaOpenNamedSocket ("kapa", "pmSource:plots");
+        if (kapa1 == -1) {
+            fprintf (stderr, "failure to open kapa; visual mode disabled\n");
+            pmVisualSetVisual(false);
+            return false;
+        }
+    }
+
+    KapaClearSections (kapa1);
+    KapaInitGraph (&graphdata);
+
+    int n;
+    float range;
+    psVector *x = psVectorAllocEmpty (psfTry->sources->n, PS_TYPE_F32);
+    psVector *y = psVectorAllocEmpty (psfTry->sources->n, PS_TYPE_F32);
+    psVector *dy = psVectorAllocEmpty(psfTry->sources->n, PS_TYPE_F32);
+
+    // section a: fractional-x pixel
+    section.dx = 1.0;
+    section.dy = 0.5;
+    section.x = 0.0;
+    section.y = 0.0;
+    section.name = NULL;
+    psStringAppend (&section.name, "a1");
+    KapaSetSection (kapa1, &section);
+    psFree (section.name);
+
+    graphdata.xmin = +32.0;
+    graphdata.xmax = -32.0;
+    graphdata.ymin = +32.0;
+    graphdata.ymax = -32.0;
+
+    // construct the plot vectors
+    n = 0;
+    for (int i = 0; i < psfTry->sources->n; i++) {
+	if (psfTry->mask->data.PS_TYPE_VECTOR_MASK_DATA[i] & PSFTRY_MASK_ALL) continue;
+
+        pmSource *source = psfTry->sources->data[i];
+        x->data.F32[n] = source->modelEXT->params->data.F32[PM_PAR_XPOS] - (int)source->modelEXT->params->data.F32[PM_PAR_XPOS];
+
+	y->data.F32[n] = psfTry->metric->data.F32[i];
+        dy->data.F32[n] = psfTry->metricErr->data.F32[i];
+        graphdata.xmin = PS_MIN(graphdata.xmin, x->data.F32[n]);
+        graphdata.xmax = PS_MAX(graphdata.xmax, x->data.F32[n]);
+        graphdata.ymin = PS_MIN(graphdata.ymin, y->data.F32[n]);
+        graphdata.ymax = PS_MAX(graphdata.ymax, y->data.F32[n]);
+	n++;
+    }
+    x->n = y->n = dy->n = n;
+
+    range = graphdata.xmax - graphdata.xmin;
+    graphdata.xmax += 0.05*range;
+    graphdata.xmin -= 0.05*range;
+    range = graphdata.ymax - graphdata.ymin;
+    graphdata.ymax += 0.05*range;
+    graphdata.ymin -= 0.05*range;
+
+    // better choice for range?
+    // graphdata.xmin = -17.0;
+    // graphdata.xmax =  -9.0;
+    graphdata.ymin = -0.51;
+    graphdata.ymax = +0.51;
+
+    KapaSetLimits (kapa1, &graphdata);
+
+    KapaSetFont (kapa1, "helvetica", 14);
+    KapaBox (kapa1, &graphdata);
+    KapaSendLabel (kapa1, "PSF Mag", KAPA_LABEL_XM);
+    KapaSendLabel (kapa1, "Ap Mag - PSF Mag", KAPA_LABEL_YM);
+
+    graphdata.color = KapaColorByName ("black");
+    graphdata.ptype = 2;
+    graphdata.size = 0.5;
+    graphdata.style = 2;
+    graphdata.etype |= 0x01;
+
+    KapaPrepPlot (kapa1, n, &graphdata);
+    KapaPlotVector (kapa1, n, x->data.F32, "x");
+    KapaPlotVector (kapa1, n, y->data.F32, "y");
+    KapaPlotVector (kapa1, n, dy->data.F32, "dym");
+    KapaPlotVector (kapa1, n, dy->data.F32, "dyp");
+
+    // *** section b: fractional-x pixel
+    section.dx = 1.0;
+    section.dy = 0.5;
+    section.x = 0.0;
+    section.y = 0.5;
+    section.name = NULL;
+    psStringAppend (&section.name, "a2");
+    KapaSetSection (kapa1, &section);
+    psFree (section.name);
+
+    graphdata.xmin = +32.0;
+    graphdata.xmax = -32.0;
+    graphdata.ymin = +32.0;
+    graphdata.ymax = -32.0;
+
+    // construct the plot vectors
+    n = 0;
+    for (int i = 0; i < psfTry->sources->n; i++) {
+	if (psfTry->mask->data.PS_TYPE_VECTOR_MASK_DATA[i] & PSFTRY_MASK_ALL) continue;
+
+        pmSource *source = psfTry->sources->data[i];
+        x->data.F32[n] = source->modelEXT->params->data.F32[PM_PAR_YPOS] - (int)source->modelEXT->params->data.F32[PM_PAR_YPOS];
+
+	y->data.F32[n] = psfTry->metric->data.F32[i];
+        dy->data.F32[n] = psfTry->metricErr->data.F32[i];
+        graphdata.xmin = PS_MIN(graphdata.xmin, x->data.F32[n]);
+        graphdata.xmax = PS_MAX(graphdata.xmax, x->data.F32[n]);
+        graphdata.ymin = PS_MIN(graphdata.ymin, y->data.F32[n]);
+        graphdata.ymax = PS_MAX(graphdata.ymax, y->data.F32[n]);
+	n++;
+    }
+    x->n = y->n = dy->n = n;
+
     range = graphdata.xmax - graphdata.xmin;
     graphdata.xmax += 0.05*range;