diff --git a/floatimg.h b/floatimg.h
index cdcc8e9..09f05bc 100644
--- a/floatimg.h
+++ b/floatimg.h
@@ -4,7 +4,7 @@
  *	http://la.buvette.org/photos/cumul
  */
 
-#define		FIMG_VERSION	131
+#define		FIMG_VERSION	132
 
 /*
  *	in memory descriptor
@@ -158,6 +158,7 @@ int fimg_desaturate(FloatImg *src, FloatImg *dst, int notused);
 
 /*	module funcs/geometry.c		*/
 int fimg_halfsize_0(FloatImg *src, FloatImg *dst, int notused);
+int fimg_halfsize_1(FloatImg *src, FloatImg *dst, int notused);
 
 int fimg_displacement_0(FloatImg *psrc, FloatImg *pdst, int flags);
 
diff --git a/funcs/geometry.c b/funcs/geometry.c
index dab2ee3..b6fcd15 100644
--- a/funcs/geometry.c
+++ b/funcs/geometry.c
@@ -26,7 +26,7 @@ fprintf(stderr, ">>> %s ( %p %p %d )\n", __func__,
 			/* no magic check here ? */
 if (dst->width || dst->height) {
 	fprintf(stderr, "*** %s: image at %p not empty\n", __func__, dst);
-	fimg_describe(dst, "destination halfsize");
+	fimg_describe(dst, "destination halfsize 0");
 	return -2;
 	}
 
@@ -55,3 +55,51 @@ for (y=0; y<hd; y++) {
 return 0;
 }
 /* --------------------------------------------------------------------- */
+int fimg_halfsize_1(FloatImg *src, FloatImg *dst, int notused)
+{
+int		wd, hd;
+int		foo, x, y, x2, y2;
+float		ac;
+
+if (dst->width || dst->height) {
+	fprintf(stderr, "*** %s: image at %p not empty\n", __func__, dst);
+	fimg_describe(dst, "destination halfsize 1");
+	return -2;
+	}
+
+wd = src->width / 2;	hd = src->height / 2;
+if ( (foo = fimg_create(dst, wd, hd, FIMG_TYPE_RGB)) ) {
+	fprintf(stderr, "%s: err create %d\n", __func__, foo);
+	return -3;
+	}
+
+#define WS  (src->width)
+#define WD  (dst->width)
+
+for (y=0; y<hd; y++) {
+	y2 = y * 2;
+	for (x=0; x<wd; x++) {
+		x2 = x * 2;
+
+		ac = src->R[(y2*WS)+x2]      + src->R[(y2*WS)+x2+1] +
+		     src->R[((1+y2)*WS)+x2]  + src->R[((1+y2)*WS)+x2+1];
+		dst->R[y*WD +x] = ac / 4.0;
+
+		ac = src->G[(y2*WS)+x2]      + src->G[(y2*WS)+x2+1] +
+		     src->G[((1+y2)*WS)+x2]  + src->G[((1+y2)*WS)+x2+1];
+		dst->G[y*WD +x] = ac / 4.0;
+
+		ac = src->B[(y2*WS)+x2]      + src->B[(y2*WS)+x2+1] +
+		     src->B[((1+y2)*WS)+x2]  + src->B[((1+y2)*WS)+x2+1];
+		dst->B[y*WD +x] = ac / 4.0;
+
+		}
+	}
+
+#undef WS
+#undef WD
+
+return 0;
+}
+/* --------------------------------------------------------------------- */
+
diff --git a/funcs/t.c b/funcs/t.c
index 64443a7..2f16c7d 100644
--- a/funcs/t.c
+++ b/funcs/t.c
@@ -21,7 +21,8 @@ float		global_fvalue;
 /* --------------------------------------------------------------------- */
 enum nCmd { Equalize=1, Rotate, Sfx0, F3x3, MIRE, Wfits, Wpng, Wtiff,
 			Histo, Hsv, Classif, Ctr2x2, Qsortrgb,
-			Displace, ReadPNG, Plasmas, Hilight, OpenEXR  };
+			Displace, ReadPNG, Plasmas, Hilight, OpenEXR,
+			Geometrie  };
 typedef struct {
 	char	*name;
 	int	Cmd;
@@ -46,6 +47,7 @@ Command commands[] = {
 	{ "plasma",	Plasmas		},
 	{ "hilight",	Hilight		},
 	{ "openexr",	OpenEXR		},
+	{ "geometrie",	Geometrie,	},
 	{ NULL,		0		}
 	} ;
 
@@ -202,6 +204,9 @@ switch(opt) {
 	case OpenEXR:
 		foo = essai_openexr(filename, outfile, 0x55);
 		break;
+	case Geometrie:
+		foo = essai_geometrie(filename, 0);
+		break;
 	default:
 		fprintf(stderr, "'%s' is a bad command\n", command);
 		exit(1);
diff --git a/funcs/tests.c b/funcs/tests.c
index 96a6250..ca5a35e 100644
--- a/funcs/tests.c
+++ b/funcs/tests.c
@@ -498,7 +498,7 @@ fimg_destroy(&fimg);
 return 0;
 }
 /* --------------------------------------------------------------------- */
-int essai_geometrie(char *infile)
+int essai_geometrie(char *infile, int notused)
 {
 FloatImg	fimg, result;
 int		foo;
@@ -516,19 +516,29 @@ else	{
 	fimg_draw_something(&fimg);
 	}
 
-foo = fimg_save_as_pnm(&fimg, "source.pnm", 0);
+// foo = fimg_save_as_pnm(&fimg, "source.pnm", 0);
 
 memset(&result, 0, sizeof(FloatImg));
 
 foo = fimg_halfsize_0(&fimg, &result, 0);
-fprintf(stderr, "retour halfsize -> %d\n", foo);
+fprintf(stderr, "retour halfsize 0 -> %d\n", foo);
 if (foo) {
 	return -2;
 	}
+if (verbosity) fimg_describe(&result, "result after halfsize 0");
+foo = fimg_save_as_pnm(&result, "halfsize0.pnm", 0);
 
-if (verbosity) fimg_describe(&result, "result after halfsize");
+fimg_destroy(&result);
+foo = fimg_halfsize_1(&fimg, &result, 0);
+fprintf(stderr, "retour halfsize 1 -> %d\n", foo);
+if (foo) {
+	return -2;
+	}
+if (verbosity) fimg_describe(&result, "result after halfsize 1");
+foo = fimg_save_as_pnm(&result, "halfsize1.pnm", 0);
 
-foo = fimg_save_as_pnm(&result, "something.pnm", 0);
+/* hop, un peu de nettoyage */
+fimg_destroy(&result);	fimg_destroy(&fimg);
 
 return 0;
 }
diff --git a/funcs/tests.h b/funcs/tests.h
index 2fb1f09..bc46751 100644
--- a/funcs/tests.h
+++ b/funcs/tests.h
@@ -19,6 +19,7 @@ int essai_ecriture_tiff(char *infile);
 int fimg_essai_hsv(char *infile);
 int essai_classif(char *infile, char *outfile, float fvalue);
 int essai_contour_2x2(char *filename, char *outfile);
+int essai_geometrie(char *infile, int notused);
 
 int fimg_essai_histo(FloatImg *src, char *outpic, int k); /* histogram.c */
 int essai_histogramme(char *fname, int k);