Index: dft.c
===================================================================
--- dft.c	(revision 2290)
+++ dft.c	(working copy)
@@ -34,9 +34,16 @@
 
 static void prepare(GeglOperation *operation)
 {
-	Babl *image_format = babl_format("RGB float");
-	Babl *frequency_format = babl_format("Y float"); /* use "Y_float" temporarily */
-
+	Babl *image_format = babl_format_new (babl_model("RGB"),
+                                              babl_type ("double"),
+                                              babl_component ("R"),
+                                              babl_component ("G"),
+                                              babl_component ("B"),
+                                              NULL);
+	Babl *frequency_format = babl_format_new (babl_model ("Y"),
+                                                  babl_type ("double"),
+                                                  babl_component ("Y"),
+                                                  NULL);
 	gegl_operation_set_format(operation, "input", image_format);
 	gegl_operation_set_format(operation, "output", frequency_format);
 }
@@ -48,17 +55,16 @@
 {
 	gint width= gegl_buffer_get_width(input);
 	gint height= gegl_buffer_get_height(input);
-	gfloat *src_buf, *dst_buf;
+	gdouble *src_buf, *dst_buf;
 	gint i, j;
 	fftw_complex *fft_out;
 	fftw_plan fftplan;
 
-	src_buf = g_new0 (gfloat, gegl_buffer_get_pixel_count (input) * 3);
-	gegl_buffer_get(input, 1.0, NULL, babl_format("RGB float"), src_buf, 
-	GEGL_AUTO_ROWSTRIDE);
+	src_buf = g_new0 (gdouble, gegl_buffer_get_pixel_count (input) * 3);
+	gegl_buffer_get(input, 1.0, NULL, NULL, src_buf, GEGL_AUTO_ROWSTRIDE);
 
 	/* fetch R component pixes */
-	dst_buf = g_new0 (gfloat, height*width);
+	dst_buf = g_new0 (gdouble, height*width);
 	for (i=0; i<width*height; i++) {
 		dst_buf[i] = src_buf[3 * i];
 	}
@@ -66,9 +72,10 @@
 	/* take DFT for the 'R' component of a RGB image */
 	fft_out = (fftw_complex*) fftw_malloc(sizeof(fftw_complex) * height
 			* FFT_HALF(width));
-	fftplan = fftw_plan_dft_r2c_2d(height, width, (float *)dst_buf, fft_out,
+	fftplan = fftw_plan_dft_r2c_2d(height, width, (double *)dst_buf, fft_out,
 									FFTW_ESTIMATE);
 	fftw_execute(fftplan);
+#if 1
 	
 	/* just for test: output the real component of the frequncy domain */
 	for (i=0; i<height; i++) {
@@ -81,7 +88,8 @@
 					fft_out[fft_complex_get_half_id(i, i, width, height)][0]/33614026;
 		}
 	}
-	gegl_buffer_set(output, NULL, babl_format("Y float"), dst_buf, GEGL_AUTO_ROWSTRIDE);
+#endif
+	gegl_buffer_set(output, NULL, NULL, dst_buf, GEGL_AUTO_ROWSTRIDE);
 	
 	fftw_destroy_plan(fftplan);
 	fftw_free(fft_out);