diff --git a/Fonderie/sfx.c b/Fonderie/sfx.c
index a826eaa..cff425f 100644
--- a/Fonderie/sfx.c
+++ b/Fonderie/sfx.c
@@ -54,14 +54,10 @@ static int pixel_trinitron(FloatImg *pimg, int pos[4], float *fvals)
 {
 int		x, y, pline, off;
 
+fimg_clear_rectangle(pimg, pos);
+
 for (y=pos[1]; y<pos[1]+pos[3]; y++) {
 	pline = y*pimg->width;
-#if 0
-	for (x=0; x<(pos[0]+pos[2]); x++) {
-		off = pline + x;
-		pimg->R[off]=pimg->G[off]=pimg->B[off]=0.0;
-		}
-#endif
 	for (x=pos[0]+2; x<(pos[0]+pos[2]-2); x++) {
 		off = pline + x;
 		/* wtf i'm doing here ? */
diff --git a/floatimg.h b/floatimg.h
index d836480..2de8bd4 100644
--- a/floatimg.h
+++ b/floatimg.h
@@ -4,7 +4,7 @@
  *	http://la.buvette.org/photos/cumul
  */
 
-#define		FIMG_VERSION	158
+#define		FIMG_VERSION	160
 
 /*
  *	in memory descriptor
@@ -108,6 +108,7 @@ typedef struct {
 
 int fimg_killborders(FloatImg *img);
 int fimg_lissage_2x2(FloatImg *img);
+int fimg_show_filter(char *title, FimgFilter3x3 *filtr);
 int fimg_filter_3x3(FloatImg *s, FloatImg *d, FimgFilter3x3 *filtr);
 
 
@@ -248,6 +249,7 @@ int parse_rectangle(char *str, FimgArea51 *r, int notused);
 int format_from_extension(char *fname);
 char * extension_from_format(int fmt);
 
+int fimg_clear_rectangle(FloatImg *pimg, int rect[4]);
 
 
 
diff --git a/funcs/rectangle.c b/funcs/rectangle.c
index 83da174..b835c6d 100644
--- a/funcs/rectangle.c
+++ b/funcs/rectangle.c
@@ -6,6 +6,8 @@
 #include  <stdio.h>
 #include  <stdlib.h>
 #include  <stdint.h>
+#include  <string.h>
+
 #include  <math.h>
 
 #include  "../floatimg.h"
@@ -23,7 +25,11 @@ fprintf(stderr, ">>> %s ( %p %p )\n", __func__, pi, coo);
 
 for (line=0; line<coo[3]; line++) {
 	off = (line+coo[1])*pi->width + coo[0];
-	fprintf(stderr, "line %d off %d\n", line, off);
+	// fprintf(stderr, "line %3d   off %8d\n", line, off);
+	/* Kaboum ! */
+	memset(pi->R + off, 0, coo[2]*sizeof(float));
+	memset(pi->G + off, 0, coo[2]*sizeof(float));
+	memset(pi->B + off, 0, coo[2]*sizeof(float));
 	}
 
 return -1;
diff --git a/funcs/t.c b/funcs/t.c
index 5882646..ad767f0 100644
--- a/funcs/t.c
+++ b/funcs/t.c
@@ -24,7 +24,7 @@ enum nCmd { Equalize=1, Rotate, Sfx0, F3x3, MIRE, Wfits, Wpng, Wtiff,
 			Histo, Hsv, Classif, Ctr2x2, Qsortrgb,
 			Displace, ReadPNG, Plasmas, Hilight, OpenEXR,
 			Geometrie, FileType, Mirror, KillRGB,
-			Pixelize,SplitLevel,DecompRgbz  };
+			Pixelize,SplitLevel,DecompRgbz, Rectangle  };
 typedef struct {
 	char	*name;
 	int	Cmd;
@@ -56,6 +56,7 @@ Command commands[] = {
 	{ "pixelize",	Pixelize	},
 	{ "spltlvl",	SplitLevel	},
 	{ "decomprgbz",	DecompRgbz	},
+	{ "rectangle",  Rectangle	},
 	{ NULL,		0		}
 	} ;
 
@@ -233,6 +234,10 @@ switch(opt) {
 	case DecompRgbz:
 		foo = essai_decomprgb(filename, outfile);
 		break;
+	case Rectangle:
+		essai_rectangle(outfile, 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 eaee9a0..6ff3e50 100644
--- a/funcs/tests.c
+++ b/funcs/tests.c
@@ -17,6 +17,31 @@
 
 extern int		verbosity;
 
+/* --------------------------------------------------------------------- */
+int essai_rectangle(char *outf, int k)
+{
+FloatImg	img;
+int		foo;
+int		rect[4];
+
+foo = fimg_create(&img, 320, 240, FIMG_TYPE_RGB);
+
+fimg_drand48(&img, 1.0);
+
+rect[0] = 100;		rect[1] = 100;
+rect[2] = 32;		rect[3] = 16;
+
+foo = fimg_clear_rectangle(&img, rect);
+
+foo = fimg_export_picture(&img, outf, 0);
+if (foo) {
+	fprintf(stderr, "%s : err %d saving result\n", __func__, foo);
+	return foo;
+	}
+
+fimg_destroy(&img);
+return 0;
+}
 /* --------------------------------------------------------------------- */
 int essai_killrgb(char *inf, char *outf)
 {