* ordered.c: r means radius, not diameter.

git-svn-id: file:///srv/caca.zoy.org/var/lib/svn/libpipi/trunk@2813 92316355-f0b4-4df1-b90c-862c8a59935f

pipi/dither/ordered.c

@@ -29,7 +29,7 @@ pipi_image_t *pipi_dither_halftone(pipi_image_t *img, double r, double angle)
 {
 #define PRECISION 4.
     pipi_image_t *ret, *kernel;
-    int k = (r * PRECISION / sqrt(2.) + .5);
+    int k = (r * PRECISION / 2. / sqrt(2.) + .5);
 
     kernel = pipi_render_halftone(k, k);
     ret = pipi_dither_ordered_ext(img, kernel, 1. / PRECISION, angle + 45.);